简介
retrofit是square出品的一个优秀的网络框架，注意，不是一个网络引擎。它的定位和Volley是一样的。
它完成了封装请求，线程切换，数据装换等一系列工作，如果自己有能力也可以封装一个这种框架，本质上是没有区别的。
retrofit使用的网络引擎是OkHttp.
而OKHttp和HTTPClient，HttpUrlConnection是一个级别的。
使用
//1 创建网络请求接口类
public interface GitHubService {
@GET("users/{user}/repos")
Call<List<Repo>> listRepos(@Path("user") String user);
}
//2 创建Retrofit实例对象
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://api.github.com/")
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.build();
//3 通过动态代理创建网络接口代理对象
GitHubService service = retrofit.create(GitHubService.class);
//4 获取Call对象
Call<List<Repo>> repos = service.listRepos("octocat");
//5 执行同步请求或异步请求
repos.execute();
repos.enqueue(callback)Retrofit
Retrofit也是使用Build模式创建的。
builder类有这些方法。从图表可以看出，我们可以调用client方法传入一个我们自定义的OkhttpClient,
调用baseUrl方法传入Host,最后调动build方法生成一个Retrofit 对象
public Retrofit build() {
//baseUrl是必须的
if (baseUrl == null) {
throw new IllegalStateException("Base URL required.");
}
//如果没有设置callFactory对象，系统自动生成一个OkhttpClient对象.因为OKHttpclient实现了 Call.Factory接口
// public class OkHttpClient implements Cloneable, Call.Factory, WebSocket.Factory
okhttp3.Call.Factory callFactory = this.callFactory;
if (callFactory == null) {
callFactory = new OkHttpClient();
}
//如果没有设置callbackExecutor，系统自动生成一个，platform.defaultCallbackExecutor，这个platform是无参构造方法里调用Platform.get()方法得到的。
/**
public Builder() {
this(Platform.get());
}**/
Executor callbackExecutor = this.callbackExecutor;
if (callbackExecutor == null) {
callbackExecutor = platform.defaultCallbackExecutor();
}
// Make a defensive copy of the adapters and add the default Call adapter.
List<CallAdapter.Factory> adapterFactories = new ArrayList<>(this.adapterFactories);
adapterFactories.add(platform.defaultCallAdapterFactory(callbackExecutor));
// Make a defensive copy of the converters.
List<Converter.Factory> converterFactories = new ArrayList<>(this.converterFactories);
return new Retrofit(callFactory, baseUrl, converterFactories, adapterFactories,
callbackExecutor, validateEagerly);
}Platform
class Platform {
private static final Platform PLATFORM = findPlatform();
static Platform get() {
return PLATFORM;
}
private static Platform findPlatform() {
try {
Class.forName("android.os.Build");
if (Build.VERSION.SDK_INT != 0) {
return new Android();
}
} catch (ClassNotFoundException ignored) {
}
try {
Class.forName("java.util.Optional");
return new Java8();
} catch (ClassNotFoundException ignored) {
}
try {
//怎么还有IOS代码呢？
Class.forName("org.robovm.apple.foundation.NSObject");
return new IOS();
} catch (ClassNotFoundException ignored) {
}
return new Platform();
}
Executor defaultCallbackExecutor() {
return null;
}
CallAdapter.Factory defaultCallAdapterFactory(Executor callbackExecutor) {
if (callbackExecutor != null) {
return new ExecutorCallAdapterFactory(callbackExecutor);
}
return DefaultCallAdapterFactory.INSTANCE;
}
boolean isDefaultMethod(Method method) {
return false;
}
Object invokeDefaultMethod(Method method, Class<?> declaringClass, Object object, Object... args)
throws Throwable {
throw new UnsupportedOperationException();
}
static class Android extends Platform {
@Override public Executor defaultCallbackExecutor() {
return new MainThreadExecutor();
}
@Override CallAdapter.Factory defaultCallAdapterFactory(Executor callbackExecutor) {
return new ExecutorCallAdapterFactory(callbackExecutor);
}
static class MainThreadExecutor implements Executor {
private final Handler handler = new Handler(Looper.getMainLooper());
@Override public void execute(Runnable r) {
handler.post(r);
}
}
}
}Retrofit 要求必须将请求API写到一个interface接口文件里，这是动态代理特性要求的。
从接口文件里我们可以看到，我们将每个请求用这种形式表达
public interface GitHubService {
@GET("users/{user}/repos")
Call<List<Repo>> listRepos(@Path("user") String user);
}
从接口文件我们可以看出，一个请求接口被各种注解所表示。
我们知道一个方法有一下关键字段组成
首先一个方法必须有描述符，返回值，方法名，参数类型，参数构成。
那我们用一个方法表示一个http请求需要哪些东西呢？
Http请求，首先我们得知道是GET请求还是POST请求，
然后就是请求头信息，请求路径，查询参数等等。
POST请求还需要Body。
Retrofit 已经提供了足够的注解来表示一个方法。
Retrofit的核心思想AOP，面向切面变成，通过动态代理的反射，将接口文件里的每个方法记性处理，也就是分析该方法的注解生成一个ServiceMethod类。
Retrofit 里有个关键的类，ServiceMethod
@SuppressWarnings("unchecked") // Single-interface proxy creation guarded by parameter safety.
public <T> T create(final Class<T> service) {
Utils.validateServiceInterface(service);
if (validateEagerly) {
eagerlyValidateMethods(service);
}
return (T) Proxy.newProxyInstance(service.getClassLoader(), new Class<?>[] { service },
new InvocationHandler() {
private final Platform platform = Platform.get();
@Override public Object invoke(Object proxy, Method method, Object... args)
throws Throwable {
// If the method is a method from Object then defer to normal invocation.
if (method.getDeclaringClass() == Object.class) {
return method.invoke(this, args);
}
if (platform.isDefaultMethod(method)) {
return platform.invokeDefaultMethod(method, service, proxy, args);
}
//创建ServiceMethod对象
ServiceMethod serviceMethod = loadServiceMethod(method);
OkHttpCall okHttpCall = new OkHttpCall<>(serviceMethod, args);
return serviceMethod.callAdapter.adapt(okHttpCall);
}
});
}从第3步我们可以看出create方法的实现就是使用了动态代理，在运行时生成了GitHubService对象。
//创建ServiceMethod对象
ServiceMethod serviceMethod = loadServiceMethod(method);
ServiceMethod loadServiceMethod(Method method) {
ServiceMethod result;
synchronized (serviceMethodCache) {
//先从换从中取改方法对应的ServiceMethod对象，如果为null就构建一个ServiceMethod对象并存入到map中，如果不为null直接返回
result = serviceMethodCache.get(method);
if (result == null) {
result = new ServiceMethod.Builder(this, method).build();
serviceMethodCache.put(method, result);
}
}
return result;
}我们可以看到loadServiceMethod(Method method)方法返回了一个ServiceMethod对象
这个serviceMethodCache对象是Retrofit的一个字段，是一个Map集合。
private final Map<Method, ServiceMethod> serviceMethodCache = new LinkedHashMap<>();
将接口文件里每个方法转换为一个ServiceMethod对象后放入改map中作为缓存，下次调用该方法后就不用再次解析改方法对象了，直接从改map里去以方法为key去取对应的ServiceMethod就行了。666
接下来看一下ServiceMethod对象的构造
ServiceMethod
final class ServiceMethod<T> {
// Upper and lower characters, digits, underscores, and hyphens, starting with a character.
static final String PARAM = "[a-zA-Z][a-zA-Z0-9_-]*";
static final Pattern PARAM_URL_REGEX = Pattern.compile("\\{(" + PARAM + ")\\}");
static final Pattern PARAM_NAME_REGEX = Pattern.compile(PARAM);
final okhttp3.Call.Factory callFactory;
final CallAdapter<?> callAdapter;
private final HttpUrl baseUrl; 主机地址
private final Converter<ResponseBody, T> responseConverter;
private final String httpMethod;
private final String relativeUrl; 相对路径
private final Headers headers; 请求头部信息
private final MediaType contentType; 请求参数类型
private final boolean hasBody; 是否有请求体
private final boolean isFormEncoded; 是否是格式化的表单
private final boolean isMultipart; 是不是分块
private final ParameterHandler<?>[] parameterHandlers;
ServiceMethod(Builder<T> builder) {
this.callFactory = builder.retrofit.callFactory();
this.callAdapter = builder.callAdapter;
this.baseUrl = builder.retrofit.baseUrl();
this.responseConverter = builder.responseConverter;
this.httpMethod = builder.httpMethod;
this.relativeUrl = builder.relativeUrl;
this.headers = builder.headers;
this.contentType = builder.contentType;
this.hasBody = builder.hasBody;
this.isFormEncoded = builder.isFormEncoded;
this.isMultipart = builder.isMultipart;
this.parameterHandlers = builder.parameterHandlers;
}
}ServiceMethod是采用Builder模式创建的。
static final class Builder<T> {
final Retrofit retrofit;
final Method method; //接口里生命的方法
final Annotation[] methodAnnotations; //方法的注解，get/post/header之类的
final Annotation[][] parameterAnnotationsArray; //方法的参数注解数组，二维数组
final Type[] parameterTypes; //方法的参数数组
Type responseType;
boolean gotField;
boolean gotPart;
boolean gotBody;
boolean gotPath;
boolean gotQuery;
boolean gotUrl;
String httpMethod;
boolean hasBody;
boolean isFormEncoded;
boolean isMultipart;
String relativeUrl;
Headers headers;
MediaType contentType;
Set<String> relativeUrlParamNames;
ParameterHandler<?>[] parameterHandlers;
Converter<ResponseBody, T> responseConverter;
CallAdapter<?> callAdapter;
public Builder(Retrofit retrofit, Method method) {
this.retrofit = retrofit;
this.method = method;
this.methodAnnotations = method.getAnnotations(); //获取方法的注解
this.parameterTypes = method.getGenericParameterTypes(); //获取被注解修饰的方法，一个数组
this.parameterAnnotationsArray = method.getParameterAnnotations(); //获取方法的参数注解信息，是一个二维数组
}Builder的构造参数需要一个Retrofit对象和一个Method对象。
首先解析方法对象，将其注解和参数注解放到对应的数组里。
首先在构造方法里获取该方法的注解,方法的参数，以及每个参数的注解。
关键就在build方法，在build方法里对方法做了一个彻底的分解
public ServiceMethod build() {
//1 处理返回结果，做一定的转换
callAdapter = createCallAdapter();
responseType = callAdapter.responseType();
if (responseType == Response.class || responseType == okhttp3.Response.class) {
throw methodError("'"
+ Utils.getRawType(responseType).getName()
+ "' is not a valid response body type. Did you mean ResponseBody?");
}
responseConverter = createResponseConverter();
//2提取方法的注解
for (Annotation annotation : methodAnnotations) {
parseMethodAnnotation(annotation);
}
//如果httpMethod为null，即没有使用方法类型注解修饰，抛出异常进行提示
if (httpMethod == null) {
throw methodError("HTTP method annotation is required (e.g., @GET, @POST, etc.).");
}
//如果没有请求体，即使用了GET，HEAD，DELETE，OPTIONS等所修饰，即不涉及到表单的提交，但是同时使用了Multipart，或者FormUrlEncoded所修饰，就报错
if (!hasBody) {
if (isMultipart) {
throw methodError(
"Multipart can only be specified on HTTP methods with request body (e.g., @POST).");
}
if (isFormEncoded) {
throw methodError("FormUrlEncoded can only be specified on HTTP methods with "
+ "request body (e.g., @POST).");
}
}
//3提取方法的参数
int parameterCount = parameterAnnotationsArray.length;
parameterHandlers = new ParameterHandler<?>[parameterCount];
for (int p = 0; p < parameterCount; p++) {
Type parameterType = parameterTypes[p];
if (Utils.hasUnresolvableType(parameterType)) {
throw parameterError(p, "Parameter type must not include a type variable or wildcard: %s",
parameterType);
}
Annotation[] parameterAnnotations = parameterAnnotationsArray[p];
if (parameterAnnotations == null) {
throw parameterError(p, "No Retrofit annotation found.");
}
parameterHandlers[p] = parseParameter(p, parameterType, parameterAnnotations);
}
//相对路径为null且gotURL为false的话，抛出异常，因为没有相对路径无法请求。
if (relativeUrl == null && !gotUrl) {
throw methodError("Missing either @%s URL or @Url parameter.", httpMethod);
}
//没有使用@FormUrlEncoded，@Multipart主机并且hasBody为false，但是gotBody为true，抛出异常，提示
Non-Body类型的HTTP method 不能参数不能使用@Body注解
if (!isFormEncoded && !isMultipart && !hasBody && gotBody) {
throw methodError("Non-body HTTP method cannot contain @Body.");
}
//使用@FormUrlEncoded修饰的方法中的参数至少有一个参数被@Field注解修饰
if (isFormEncoded && !gotField) {
throw methodError("Form-encoded method must contain at least one @Field.");
}
//使用@Multipart修饰的方法中的参数至少有一个参数被@Part注解修饰
if (isMultipart && !gotPart) {
throw methodError("Multipart method must contain at least one @Part.");
}
//4 当前Builder对象初始化完毕，可以用来够着ServiceMethod对象。
return new ServiceMethod<>(this);
}处理返回结果
private CallAdapter<?> createCallAdapter() {
//获取方法的返回结果,如果有不能解析的类型则抛出异常，也就是说接口中定义的方法的返回值不能使用泛型
Type returnType = method.getGenericReturnType();
if (Utils.hasUnresolvableType(returnType)) {
throw methodError(
"Method return type must not include a type variable or wildcard: %s", returnType);
}
//接口里的方法不能返回void
if (returnType == void.class) {
throw methodError("Service methods cannot return void.");
}
Annotation[] annotations = method.getAnnotations();
try {
return retrofit.callAdapter(returnType, annotations);
} catch (RuntimeException e) { // Wide exception range because factories are user code.
//用户自定义的Adapter可能不能正确的处理返回结果，这时候抛出异常
throw methodError(e, "Unable to create call adapter for %s", returnType);
}
}解析方法注解
1处处理方法的注解，就是先处理GET/POST/Header等注解信息
private void parseMethodAnnotation(Annotation annotation) {
if (annotation instanceof DELETE) {
parseHttpMethodAndPath("DELETE", ((DELETE) annotation).value(), false);
} else if (annotation instanceof GET) {
parseHttpMethodAndPath("GET", ((GET) annotation).value(), false);
} else if (annotation instanceof HEAD) {
parseHttpMethodAndPath("HEAD", ((HEAD) annotation).value(), false);
if (!Void.class.equals(responseType)) {
throw methodError("HEAD method must use Void as response type.");
}
} else if (annotation instanceof PATCH) {
parseHttpMethodAndPath("PATCH", ((PATCH) annotation).value(), true);
} else if (annotation instanceof POST) {
parseHttpMethodAndPath("POST", ((POST) annotation).value(), true);
} else if (annotation instanceof PUT) {
parseHttpMethodAndPath("PUT", ((PUT) annotation).value(), true);
} else if (annotation instanceof OPTIONS) {
parseHttpMethodAndPath("OPTIONS", ((OPTIONS) annotation).value(), false);
} else if (annotation instanceof HTTP) {
HTTP http = (HTTP) annotation;
parseHttpMethodAndPath(http.method(), http.path(), http.hasBody());
} else if (annotation instanceof retrofit2.http.Headers) {
headers注解
String[] headersToParse = ((retrofit2.http.Headers) annotation).value();
if (headersToParse.length == 0) {
throw methodError("@Headers annotation is empty.");
}
headers = parseHeaders(headersToParse);
} else if (annotation instanceof Multipart) {//如果是Multipart注解
if (isFormEncoded) {
//如果同时使用了FormUrlEncoded注解报错
throw methodError("Only one encoding annotation is allowed.");
}
isMultipart = true;
} else if (annotation instanceof FormUrlEncoded) {
if (isMultipart) {
//如果同时使用了Multipart注解报错,从这我们可以看出一个方法不能同时被Multipart和FormUrlEncoded所修饰
throw methodError("Only one encoding annotation is allowed.");
}
isFormEncoded = true;
}
}然后根据具体的注解类型，在做进一步的处理，这里主要分析GET/POST/HEADER/ 等注解
@GET
else if (annotation instanceof GET) {
parseHttpMethodAndPath("GET", ((GET) annotation).value(), false);
} get类型的请求，没有请求体
private void parseHttpMethodAndPath(String httpMethod, String value, boolean hasBody) {
//如果该Builder已经有HTTPMethod了就不能改变了，直接抛异常
if (this.httpMethod != null) {
throw methodError("Only one HTTP method is allowed. Found: %s and %s.",
this.httpMethod, httpMethod);
}
//将HTTPMethod赋值给httpMethod对象，Get、Post、Delete等
this.httpMethod = httpMethod;
this.hasBody = hasBody;//是否有请求体
//如果value为null，返回，因为value参数的值其实就是relativeURL。所以不能为null
if (value.isEmpty()) {
return;
}
// Get the relative URL path and existing query string, if present.
int question = value.indexOf('?');
if (question != -1 && question < value.length() - 1) {
// Ensure the query string does not have any named parameters.
String queryParams = value.substring(question + 1);
//获取查询参数
Matcher queryParamMatcher = PARAM_URL_REGEX.matcher(queryParams);
if (queryParamMatcher.find()) {
//如果在value里面找到里查询参数的话，抛出异常。因为查询参数可以使用@Query注解来动态配置。
throw methodError("URL query string \"%s\" must not have replace block. "
+ "For dynamic query parameters use @Query.", queryParams);
}
}
this.relativeUrl = value; //将value赋值给relativeUrl
this.relativeUrlParamNames = parsePathParameters(value); //获取value里面的path占位符，如果有的话
}再来看下解析value里的path占位符的方法。
/**
获取已知URI里面的路径集合，如果一个参数被使用了两次，它只会在set中出现一次，好拗口啊，使用LinkedHashSet来保存path参数集合，保证了路径参数的顺序。
* Gets the set of unique path parameters used in the given URI. If a parameter is used twice
* in the URI, it will only show up once in the set.
*/
static Set<String> parsePathParameters(String path) {
Matcher m = PARAM_URL_REGEX.matcher(path);
Set<String> patterns = new LinkedHashSet<>();
while (m.find()) {
patterns.add(m.group(1));
}
return patterns;
}至此，GET方法的相关的注解分析完毕
@POST
else if (annotation instanceof POST) {
parseHttpMethodAndPath("POST", ((POST) annotation).value(), true);
} POST类型的请求，没有请求体。所以hasBody参数为true。
parseHttpMethodAndPath()方法已将在GET方法里面分析过了，这里面都一样。
其他的请求类型也是大同小异。
然后接着分析方法的Header注解
@Headers
else if (annotation instanceof retrofit2.http.Headers) {
// 首先获取Headers注解的值，是一个字符串数组。
String[] headersToParse = ((retrofit2.http.Headers) annotation).value();
如果header注解长度为0，抛出异常，所以使用了header注解必须设置值，不能存在空的header
if (headersToParse.length == 0) {
throw methodError("@Headers annotation is empty.");
}
处理header信息，我猜肯定是一个map
headers = parseHeaders(headersToParse);啊，居然不是，666.因为header不是KV结构的数据类型，而是一个key可以对应多个值。理论上可以使用Map<String,Set<String>>表示。
private Headers parseHeaders(String[] headers) {
Headers.Builder builder = new Headers.Builder();
for (String header : headers) {
// header以“:"分割，前面是key,后面是value
int colon = header.indexOf(':');
if (colon == -1 || colon == 0 || colon == header.length() - 1) {
//header必须是key:value格式表示，不然报错
throw methodError(
"@Headers value must be in the form \"Name: Value\". Found: \"%s\"", header);
}
String headerName = header.substring(0, colon); //key值
String headerValue = header.substring(colon + 1).trim(); //value值，必须是一个数组，艹，又猜错了。
if ("Content-Type".equalsIgnoreCase(headerName)) {
//遇到"Content-Type"字段。还需要获得具体的MediaType。
MediaType type = MediaType.parse(headerValue);
if (type == null) {
//如果mediaType为null。抛出一个type畸形的错误。
throw methodError("Malformed content type: %s", headerValue);
}
contentType = type;
} else {
将header的key和value加入到Builder里面。
builder.add(headerName, headerValue);
}
}
最后调用build方法生成一个Header对爱。
return builder.build();
}/**
* Add a header with the specified name and value. Does validation of header names and values.
*/
public Builder add(String name, String value) {
checkNameAndValue(name, value);
return addLenient(name, value);
}Builder addLenient(String name, String value) {
namesAndValues.add(name);
namesAndValues.add(value.trim());
return this;
}final List<String> namesAndValues = new ArrayList<>(20);namesAndValues是Header.Builder类的一种子段。可见在Builder内部header信息是按照key/value异常放到一个String集合里面的。为什么不放到一个Map里面呢，不懂。
总之，最后就是讲方法的Headers注解信息提取完毕。
处理方法参数
int parameterCount = parameterAnnotationsArray.length; //求得数组的长度
parameterHandlers = new ParameterHandler<?>[parameterCount];
for (int p = 0; p < parameterCount; p++) {
Type parameterType = parameterTypes[p]; //便利参数，依次处理参数
//如果参数不能解析，抛出异常
if (Utils.hasUnresolvableType(parameterType)) {
throw parameterError(p, "Parameter type must not include a type variable or wildcard: %s",
parameterType);
}
//获取第p个参数的注解数组，如果没有注解抛出异常，可见，使用了Retrofit，接口方法中每个参数都必须使用注解进行修饰。
Annotation[] parameterAnnotations = parameterAnnotationsArray[p];
if (parameterAnnotations == null) {
throw parameterError(p, "No Retrofit annotation found.");
}
//解析方法中的参数，存入parameterHandlers[]数组中。
parameterHandlers[p] = parseParameter(p, parameterType, parameterAnnotations);
}参数校验
Utils.hasUnresolvableType(parameterType)，这个方法是对参数的类型做个校验。
static boolean hasUnresolvableType(Type type) {
//如果参数是引用数据类型，返回false，可见，接口定义中方法的参数只能是基本数据类型
if (type instanceof Class<?>) {
return false;
}
//如果参数是泛型
if (type instanceof ParameterizedType) {
ParameterizedType parameterizedType = (ParameterizedType) type;
//去除泛型类中的实际类型，遍历
for (Type typeArgument : parameterizedType.getActualTypeArguments()) {
//如果有一个泛型参数是基本数据类型，返回true，都不是返回false
if (hasUnresolvableType(typeArgument)) {
return true;
}
}
return false;
}
//如果参数是泛型数组类型
if (type instanceof GenericArrayType) {
return hasUnresolvableType(((GenericArrayType) type).getGenericComponentType());
}
if (type instanceof TypeVariable) {
return true;
}
if (type instanceof WildcardType) {
return true;
}
String className = type == null ? "null" : type.getClass().getName();
throw new IllegalArgumentException("Expected a Class, ParameterizedType, or "
+ "GenericArrayType, but <" + type + "> is of type " + className);
}
解析参数
parameterHandlers[p] = parseParameter(p, parameterType, parameterAnnotations);
private ParameterHandler<?> parseParameter(
int p, Type parameterType, Annotation[] annotations) {
ParameterHandler<?> result = null;
//遍历参数的注解数组，调用parseParameterAnnotation()
for (Annotation annotation : annotations) {
ParameterHandler<?> annotationAction = parseParameterAnnotation(
p, parameterType, annotations, annotation);
//如果该注解没有返回，则解析下一个注解
if (annotationAction == null) {
continue;
}
if (result != null) {
throw parameterError(p, "Multiple Retrofit annotations found, only one allowed.");
}
result = annotationAction; //将解析的结果赋值给Result
}
//如果注解为null，抛出异常。这个地方永远不会调用，因为在获取注解数组之前就做过判断了，如果注解数组为null，直接抛异常，Line197-Line200 in ServiceMethod.Builder中
if (result == null) {
throw parameterError(p, "No Retrofit annotation found.");
}
return result;
}获取参数注解信息
再来看看parseParameterAnnotation()方法,内容略多
private ParameterHandler<?> parseParameterAnnotation(
int p, Type type, Annotation[] annotations, Annotation annotation) {
if (annotation instanceof Url) {
//如果使用了Url注解，
if (gotUrl) {
//如果gotUrl为true，因为gotURL默认为false，说明之前处理过Url注解了,抛出多个@Url注解异常
throw parameterError(p, "Multiple @Url method annotations found.");
}
if (gotPath) {
//如果gotPath为true，抛出异常，说明@Path注解不能和@Url注解一起使用
throw parameterError(p, "@Path parameters may not be used with @Url.");
}
if (gotQuery) {
//如果gotQuery为true，抛出异常，说明@Url注解不能用在@Query注解后面
throw parameterError(p, "A @Url parameter must not come after a @Query");
}
if (relativeUrl != null) {
//如果relativeUrl不为null,抛出异常，说明使用了@Url注解，relativeUrl必须为null
throw parameterError(p, "@Url cannot be used with @%s URL", httpMethod);
}
gotUrl = true;
----------------------------------------------------------------------------------------
//如果参数类型是HttpURL，String，URI或者参数类型是“android.net.Uri",返回ParameterHandler.RelativeUrl()，实际是交由这个类处理
if (type == HttpUrl.class
|| type == String.class
|| type == URI.class
|| (type instanceof Class && "android.net.Uri".equals(((Class<?>) type).getName()))) {
return new ParameterHandler.RelativeUrl();
} else {
//不然就抛出异常，也就是说@Url注解必须使用在okhttp3.HttpUrl, String, java.net.URI, or android.net.Uri 这几种类型的参数上。
throw parameterError(p,
"@Url must be okhttp3.HttpUrl, String, java.net.URI, or android.net.Uri type.");
}
------------------------------------------------------------------------------------------
} else if (annotation instanceof Path) { //@Path注解
//如果gotQuery为true。抛出异常，因为@Path修饰的参数是路径的占位符。不是查询参数，不能使用@Query注解修饰
if (gotQuery) {
throw parameterError(p, "A @Path parameter must not come after a @Query.");
}
if (gotUrl) {
throw parameterError(p, "@Path parameters may not be used with @Url.");
}
//如果相对路径为null，那@path注解也就无意义了。
if (relativeUrl == null) {
throw parameterError(p, "@Path can only be used with relative url on @%s", httpMethod);
}
gotPath = true;
Path path = (Path) annotation;
String name = path.value(); //获取@Path注解的值
validatePathName(p, name); //对改值进行校验，1该value必须是合法字符，2:该相对路径必须包含相应的占位符
//然后将改参数的所有注解进行处理，最终调用ParameterHandler.Path进行处理。
Converter<?, String> converter = retrofit.stringConverter(type, annotations);
return new ParameterHandler.Path<>(name, converter, path.encoded());
} else if (annotation instanceof Query) { //Query注解，看不太懂，最后也是调用ParameterHandler.Query进行处理
Query query = (Query) annotation;
String name = query.value();
boolean encoded = query.encoded();
Class<?> rawParameterType = Utils.getRawType(type);
gotQuery = true;
if (Iterable.class.isAssignableFrom(rawParameterType)) {
if (!(type instanceof ParameterizedType)) {
throw parameterError(p, rawParameterType.getSimpleName()
+ " must include generic type (e.g., "
+ rawParameterType.getSimpleName()
+ "<String>)");
}
ParameterizedType parameterizedType = (ParameterizedType) type;
Type iterableType = Utils.getParameterUpperBound(0, parameterizedType);
Converter<?, String> converter =
retrofit.stringConverter(iterableType, annotations);
return new ParameterHandler.Query<>(name, converter, encoded).iterable();
} else if (rawParameterType.isArray()) {
Class<?> arrayComponentType = boxIfPrimitive(rawParameterType.getComponentType());
Converter<?, String> converter =
retrofit.stringConverter(arrayComponentType, annotations);
return new ParameterHandler.Query<>(name, converter, encoded).array();
} else {
Converter<?, String> converter =
retrofit.stringConverter(type, annotations);
return new ParameterHandler.Query<>(name, converter, encoded);
}
} else if (annotation instanceof QueryMap) {
Class<?> rawParameterType = Utils.getRawType(type);
if (!Map.class.isAssignableFrom(rawParameterType)) {
throw parameterError(p, "@QueryMap parameter type must be Map.");
}
Type mapType = Utils.getSupertype(type, rawParameterType, Map.class);
if (!(mapType instanceof ParameterizedType)) {
throw parameterError(p, "Map must include generic types (e.g., Map<String, String>)");
}
ParameterizedType parameterizedType = (ParameterizedType) mapType;
Type keyType = Utils.getParameterUpperBound(0, parameterizedType);
if (String.class != keyType) {
throw parameterError(p, "@QueryMap keys must be of type String: " + keyType);
}
Type valueType = Utils.getParameterUpperBound(1, parameterizedType);
Converter<?, String> valueConverter =
retrofit.stringConverter(valueType, annotations);
return new ParameterHandler.QueryMap<>(valueConverter, ((QueryMap) annotation).encoded());
} else if (annotation instanceof Header) {
Header header = (Header) annotation;
String name = header.value();
Class<?> rawParameterType = Utils.getRawType(type);
if (Iterable.class.isAssignableFrom(rawParameterType)) {
if (!(type instanceof ParameterizedType)) {
throw parameterError(p, rawParameterType.getSimpleName()
+ " must include generic type (e.g., "
+ rawParameterType.getSimpleName()
+ "<String>)");
}
ParameterizedType parameterizedType = (ParameterizedType) type;
Type iterableType = Utils.getParameterUpperBound(0, parameterizedType);
Converter<?, String> converter =
retrofit.stringConverter(iterableType, annotations);
return new ParameterHandler.Header<>(name, converter).iterable();
} else if (rawParameterType.isArray()) {
Class<?> arrayComponentType = boxIfPrimitive(rawParameterType.getComponentType());
Converter<?, String> converter =
retrofit.stringConverter(arrayComponentType, annotations);
return new ParameterHandler.Header<>(name, converter).array();
} else {
Converter<?, String> converter =
retrofit.stringConverter(type, annotations);
return new ParameterHandler.Header<>(name, converter);
}
} else if (annotation instanceof HeaderMap) {
Class<?> rawParameterType = Utils.getRawType(type);
if (!Map.class.isAssignableFrom(rawParameterType)) {
throw parameterError(p, "@HeaderMap parameter type must be Map.");
}
Type mapType = Utils.getSupertype(type, rawParameterType, Map.class);
if (!(mapType instanceof ParameterizedType)) {
throw parameterError(p, "Map must include generic types (e.g., Map<String, String>)");
}
ParameterizedType parameterizedType = (ParameterizedType) mapType;
Type keyType = Utils.getParameterUpperBound(0, parameterizedType);
if (String.class != keyType) {
throw parameterError(p, "@HeaderMap keys must be of type String: " + keyType);
}
Type valueType = Utils.getParameterUpperBound(1, parameterizedType);
Converter<?, String> valueConverter =
retrofit.stringConverter(valueType, annotations);
return new ParameterHandler.HeaderMap<>(valueConverter);
} else if (annotation instanceof Field) {
if (!isFormEncoded) {
throw parameterError(p, "@Field parameters can only be used with form encoding.");
}
Field field = (Field) annotation;
String name = field.value();
boolean encoded = field.encoded();
gotField = true;
Class<?> rawParameterType = Utils.getRawType(type);
if (Iterable.class.isAssignableFrom(rawParameterType)) {
if (!(type instanceof ParameterizedType)) {
throw parameterError(p, rawParameterType.getSimpleName()
+ " must include generic type (e.g., "
+ rawParameterType.getSimpleName()
+ "<String>)");
}
ParameterizedType parameterizedType = (ParameterizedType) type;
Type iterableType = Utils.getParameterUpperBound(0, parameterizedType);
Converter<?, String> converter =
retrofit.stringConverter(iterableType, annotations);
return new ParameterHandler.Field<>(name, converter, encoded).iterable();
} else if (rawParameterType.isArray()) {
Class<?> arrayComponentType = boxIfPrimitive(rawParameterType.getComponentType());
Converter<?, String> converter =
retrofit.stringConverter(arrayComponentType, annotations);
return new ParameterHandler.Field<>(name, converter, encoded).array();
} else {
Converter<?, String> converter =
retrofit.stringConverter(type, annotations);
return new ParameterHandler.Field<>(name, converter, encoded);
}
} else if (annotation instanceof FieldMap) {
if (!isFormEncoded) {
throw parameterError(p, "@FieldMap parameters can only be used with form encoding.");
}
Class<?> rawParameterType = Utils.getRawType(type);
if (!Map.class.isAssignableFrom(rawParameterType)) {
throw parameterError(p, "@FieldMap parameter type must be Map.");
}
Type mapType = Utils.getSupertype(type, rawParameterType, Map.class);
if (!(mapType instanceof ParameterizedType)) {
throw parameterError(p,
"Map must include generic types (e.g., Map<String, String>)");
}
ParameterizedType parameterizedType = (ParameterizedType) mapType;
Type keyType = Utils.getParameterUpperBound(0, parameterizedType);
if (String.class != keyType) {
throw parameterError(p, "@FieldMap keys must be of type String: " + keyType);
}
Type valueType = Utils.getParameterUpperBound(1, parameterizedType);
Converter<?, String> valueConverter =
retrofit.stringConverter(valueType, annotations);
gotField = true;
return new ParameterHandler.FieldMap<>(valueConverter, ((FieldMap) annotation).encoded());
} else if (annotation instanceof Part) {
if (!isMultipart) {
throw parameterError(p, "@Part parameters can only be used with multipart encoding.");
}
Part part = (Part) annotation;
gotPart = true;
String partName = part.value();
Class<?> rawParameterType = Utils.getRawType(type);
if (partName.isEmpty()) {
if (Iterable.class.isAssignableFrom(rawParameterType)) {
if (!(type instanceof ParameterizedType)) {
throw parameterError(p, rawParameterType.getSimpleName()
+ " must include generic type (e.g., "
+ rawParameterType.getSimpleName()
+ "<String>)");
}
ParameterizedType parameterizedType = (ParameterizedType) type;
Type iterableType = Utils.getParameterUpperBound(0, parameterizedType);
if (!MultipartBody.Part.class.isAssignableFrom(Utils.getRawType(iterableType))) {
throw parameterError(p,
"@Part annotation must supply a name or use MultipartBody.Part parameter type.");
}
return ParameterHandler.RawPart.INSTANCE.iterable();
} else if (rawParameterType.isArray()) {
Class<?> arrayComponentType = rawParameterType.getComponentType();
if (!MultipartBody.Part.class.isAssignableFrom(arrayComponentType)) {
throw parameterError(p,
"@Part annotation must supply a name or use MultipartBody.Part parameter type.");
}
return ParameterHandler.RawPart.INSTANCE.array();
} else if (MultipartBody.Part.class.isAssignableFrom(rawParameterType)) {
return ParameterHandler.RawPart.INSTANCE;
} else {
throw parameterError(p,
"@Part annotation must supply a name or use MultipartBody.Part parameter type.");
}
} else {
Headers headers =
Headers.of("Content-Disposition", "form-data; name=\"" + partName + "\"",
"Content-Transfer-Encoding", part.encoding());
if (Iterable.class.isAssignableFrom(rawParameterType)) {
if (!(type instanceof ParameterizedType)) {
throw parameterError(p, rawParameterType.getSimpleName()
+ " must include generic type (e.g., "
+ rawParameterType.getSimpleName()
+ "<String>)");
}
ParameterizedType parameterizedType = (ParameterizedType) type;
Type iterableType = Utils.getParameterUpperBound(0, parameterizedType);
if (MultipartBody.Part.class.isAssignableFrom(Utils.getRawType(iterableType))) {
throw parameterError(p, "@Part parameters using the MultipartBody.Part must not "
+ "include a part name in the annotation.");
}
Converter<?, RequestBody> converter =
retrofit.requestBodyConverter(iterableType, annotations, methodAnnotations);
return new ParameterHandler.Part<>(headers, converter).iterable();
} else if (rawParameterType.isArray()) {
Class<?> arrayComponentType = boxIfPrimitive(rawParameterType.getComponentType());
if (MultipartBody.Part.class.isAssignableFrom(arrayComponentType)) {
throw parameterError(p, "@Part parameters using the MultipartBody.Part must not "
+ "include a part name in the annotation.");
}
Converter<?, RequestBody> converter =
retrofit.requestBodyConverter(arrayComponentType, annotations, methodAnnotations);
return new ParameterHandler.Part<>(headers, converter).array();
} else if (MultipartBody.Part.class.isAssignableFrom(rawParameterType)) {
throw parameterError(p, "@Part parameters using the MultipartBody.Part must not "
+ "include a part name in the annotation.");
} else {
Converter<?, RequestBody> converter =
retrofit.requestBodyConverter(type, annotations, methodAnnotations);
return new ParameterHandler.Part<>(headers, converter);
}
}
} else if (annotation instanceof PartMap) {
if (!isMultipart) {
throw parameterError(p, "@PartMap parameters can only be used with multipart encoding.");
}
gotPart = true;
Class<?> rawParameterType = Utils.getRawType(type);
if (!Map.class.isAssignableFrom(rawParameterType)) {
throw parameterError(p, "@PartMap parameter type must be Map.");
}
Type mapType = Utils.getSupertype(type, rawParameterType, Map.class);
if (!(mapType instanceof ParameterizedType)) {
throw parameterError(p, "Map must include generic types (e.g., Map<String, String>)");
}
ParameterizedType parameterizedType = (ParameterizedType) mapType;
Type keyType = Utils.getParameterUpperBound(0, parameterizedType);
if (String.class != keyType) {
throw parameterError(p, "@PartMap keys must be of type String: " + keyType);
}
Type valueType = Utils.getParameterUpperBound(1, parameterizedType);
if (MultipartBody.Part.class.isAssignableFrom(Utils.getRawType(valueType))) {
throw parameterError(p, "@PartMap values cannot be MultipartBody.Part. "
+ "Use @Part List<Part> or a different value type instead.");
}
Converter<?, RequestBody> valueConverter =
retrofit.requestBodyConverter(valueType, annotations, methodAnnotations);
PartMap partMap = (PartMap) annotation;
return new ParameterHandler.PartMap<>(valueConverter, partMap.encoding());
} else if (annotation instanceof Body) {
if (isFormEncoded || isMultipart) {
throw parameterError(p,
"@Body parameters cannot be used with form or multi-part encoding.");
}
if (gotBody) {
throw parameterError(p, "Multiple @Body method annotations found.");
}
Converter<?, RequestBody> converter;
try {
converter = retrofit.requestBodyConverter(type, annotations, methodAnnotations);
} catch (RuntimeException e) {
// Wide exception range because factories are user code.
throw parameterError(e, p, "Unable to create @Body converter for %s", type);
}
gotBody = true;
return new ParameterHandler.Body<>(converter);
}
return null; // Not a Retrofit annotation.找不到该注解
}从上面可以看出，改立参数注解的套路就是：先判断该注解的类型，然后使用策略模式分别调用ParameterHandler里对应的子类来处理
写到这里我已经晕了。晕晕乎乎好舒服
@Header
使用场景
有时候我们需要动态的设置请求header中的某个请求头的值，这个时候就可以使用@Header来修饰个参数。
最终都是讲header里的信息提取到Request里面
static final class Header<T> extends ParameterHandler<T> {
private final String name;
private final Converter<T, String> valueConverter;
Header(String name, Converter<T, String> valueConverter) {
this.name = checkNotNull(name, "name == null");
this.valueConverter = valueConverter;
}
@Override void apply(RequestBuilder builder, T value) throws IOException {
if (value == null) return; // Skip null values.
builder.addHeader(name, valueConverter.convert(value));
}
}void addHeader(String name, String value) {
if ("Content-Type".equalsIgnoreCase(name)) {
MediaType type = MediaType.parse(value);
if (type == null) {
throw new IllegalArgumentException("Malformed content type: " + value);
}
contentType = type;
} else {
requestBuilder.addHeader(name, value);
}
}调用requestBuilder.addHeader()方法。
这个requestBuilder是OKHttp中Request的内部静态类Builder类的一个对象。
private final Request.Builder requestBuilder;从中我们可以看出最后将@Header注释的参数的值解析后添加到Request对象中的Header信息里。
@Path
使用场景
有时候请求路径是不定的，即请求路径里的某个segment是变化的，也就是需要我们使用参数来动态的改变，这个时候我们就需要使用@Path 来修饰这个参数
static final class Path<T> extends ParameterHandler<T> {
private final String name; //参数名，占位符
private final Converter<T, String> valueConverter;
private final boolean encoded; //是否编码
Path(String name, Converter<T, String> valueConverter, boolean encoded) {
this.name = checkNotNull(name, "name == null");
this.valueConverter = valueConverter;
this.encoded = encoded;
}
@Override void apply(RequestBuilder builder, T value) throws IOException {
if (value == null) {
throw new IllegalArgumentException(
"Path parameter \"" + name + "\" value must not be null.");
}
builder.addPathParam(name, valueConverter.convert(value), encoded);
}
}void addPathParam(String name, String value, boolean encoded) {
if (relativeUrl == null) {
// The relative URL is cleared when the first query parameter is set.
throw new AssertionError();
}
//将占位符”{name}”使用value替换
relativeUrl = relativeUrl.replace("{" + name + "}", canonicalizeForPath(value, encoded));
}@Query
使用场景
@Query用来修饰接口方法中的查询字段
static final class Query<T> extends ParameterHandler<T> {
private final String name;
private final Converter<T, String> valueConverter;
private final boolean encoded;
Query(String name, Converter<T, String> valueConverter, boolean encoded) {
this.name = checkNotNull(name, "name == null");
this.valueConverter = valueConverter;
this.encoded = encoded;
}
@Override void apply(RequestBuilder builder, T value) throws IOException {
if (value == null) return; // Skip null values.
builder.addQueryParam(name, valueConverter.convert(value), encoded);
}
}//将查询参数组合到相对路径上。
void addQueryParam(String name, String value, boolean encoded) {
if (relativeUrl != null) {
// Do a one-time combination of the built relative URL and the base URL.
urlBuilder = baseUrl.newBuilder(relativeUrl);
if (urlBuilder == null) {
throw new IllegalArgumentException(
"Malformed URL. Base: " + baseUrl + ", Relative: " + relativeUrl);
}
relativeUrl = null;
}
if (encoded) {
urlBuilder.addEncodedQueryParameter(name, value);
} else {
urlBuilder.addQueryParameter(name, value);
}
}@QueryMap
使用场景
当接口中的一个 方法有比较多的查询字段时，全部定义到方法中时比较麻烦且容易出错，这个使用我们完全可以将所有的查询参数放到一个Map里面。
可想而知，其内部实现必定是遍历map ，然后像处理@Query参数一样调用addQueryParam()处理每个查询参数。
static final class FieldMap<T> extends ParameterHandler<Map<String, T>> {
private final Converter<T, String> valueConverter;
private final boolean encoded;
FieldMap(Converter<T, String> valueConverter, boolean encoded) {
this.valueConverter = valueConverter;
this.encoded = encoded;
}
@Override void apply(RequestBuilder builder, Map<String, T> value) throws IOException {
if (value == null) {
throw new IllegalArgumentException("Field map was null.");
}
for (Map.Entry<String, T> entry : value.entrySet()) {
String entryKey = entry.getKey();
if (entryKey == null) {
throw new IllegalArgumentException("Field map contained null key.");
}
T entryValue = entry.getValue();
if (entryValue == null) {
throw new IllegalArgumentException(
"Field map contained null value for key '" + entryKey + "'.");
}
//果然不假
builder.addFormField(entryKey, valueConverter.convert(entryValue), encoded);
}
}
}
@Field
使用场景
@Field注解一般用在表单参数的提交上
static final class Field<T> extends ParameterHandler<T> {
private final String name; //参数名字
private final Converter<T, String> valueConverter; //参数值转换器
private final boolean encoded; //是否编码
Field(String name, Converter<T, String> valueConverter, boolean encoded) {
this.name = checkNotNull(name, "name == null");
this.valueConverter = valueConverter;
this.encoded = encoded;
}
@Override void apply(RequestBuilder builder, T value) throws IOException {
if (value == null) return; // Skip null values. 所以使用@Field修饰的字段，是不会上传到服务器的。
//调用ResuestBuilder对象的具体想法来处理@Field修饰的表单字段
builder.addFormField(name, valueConverter.convert(value), encoded);
}
}void addFormField(String name, String value, boolean encoded) {
//根据参数值是否被编码，调用不同的方法。formBuilder是OKHttp中的一个类。也是使用Builder模式创建的。
if (encoded) {
formBuilder.addEncoded(name, value);
} else {
formBuilder.add(name, value);
}
}
@FieldMap
@FieldMap
使用场景
假如表单参数有很多个，我们可以使用一个Map<String,String>来表示，然后使用@FieldMap注解来修饰该参数就行了。可想而知，如同@QueryMap一样，其内部实现肯定是遍历Map，然后像处理@Field参数一样调用
builder.addFormField(name, valueConverter.convert(value), encoded);
@Body
使用场景
在以下需要提交表单的请求里，我们可以使用@Field,@FieldMap,我们还可以使用@Body来修饰我们提交的表单数据，这个时候我们需要定义一个Bean类，Bean类的各个Field必须和表单字段的key一样
static final class Body<T> extends ParameterHandler<T> {
private final Converter<T, RequestBody> converter;
Body(Converter<T, RequestBody> converter) {
this.converter = converter;
}
@Override void apply(RequestBuilder builder, T value) {
if (value == null) {
throw new IllegalArgumentException("Body parameter value must not be null.");
}
RequestBody body;
try {
body = converter.convert(value);
} catch (IOException e) {
throw new RuntimeException("Unable to convert " + value + " to RequestBody", e);
}
builder.setBody(body);
}
}这里Retrofit并没有像@Field一样处理表单参数。仔细想想也对，因为凡是提交的表单数据都需要放到请求体里面，即使使用@Field，@FieldMap提交的数据，最终还是需要放到请求体里面。
@Part
@RawPart
@PartMap
以上三个注解都是使用修饰上传文件的参数的，
结论
从对上面的分析可以知道，我们在提取使用注解修饰的参数后将值存放到RequestBuilder对象里。
这里又引入了RequestBuilder类
RequestBuilder
final class RequestBuilder {
private static final char[] HEX_DIGITS =
{ '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
private static final String PATH_SEGMENT_ALWAYS_ENCODE_SET = " \"<>^`{}|\\?#";
private final String method; //方法类型
private final HttpUrl baseUrl; //scheme+host
private String relativeUrl; //相对路径
private HttpUrl.Builder urlBuilder; //URL构造器
private final Request.Builder requestBuilder; //OkHttp中Request构造器
private MediaType contentType; //提交表单的数据类型
private final boolean hasBody; //是否有请求体
private MultipartBody.Builder multipartBuilder; //上传文件的构造器
private FormBody.Builder formBuilder; //表单数据的构造器
private RequestBody body; //请求体
RequestBuilder(String method, HttpUrl baseUrl, String relativeUrl, Headers headers,
MediaType contentType, boolean hasBody, boolean isFormEncoded, boolean isMultipart) {
this.method = method;
this.baseUrl = baseUrl;
this.relativeUrl = relativeUrl;
this.requestBuilder = new Request.Builder();
this.contentType = contentType;
this.hasBody = hasBody;
if (headers != null) {
requestBuilder.headers(headers);
}
if (isFormEncoded) {
// Will be set to 'body' in 'build'.
formBuilder = new FormBody.Builder();
} else if (isMultipart) {
// Will be set to 'body' in 'build'.
multipartBuilder = new MultipartBody.Builder();
multipartBuilder.setType(MultipartBody.FORM);
}
}
void setRelativeUrl(Object relativeUrl) {
if (relativeUrl == null) throw new NullPointerException("@Url parameter is null.");
this.relativeUrl = relativeUrl.toString();
}
void addHeader(String name, String value) {
if ("Content-Type".equalsIgnoreCase(name)) {
MediaType type = MediaType.parse(value);
if (type == null) {
throw new IllegalArgumentException("Malformed content type: " + value);
}
contentType = type;
} else {
requestBuilder.addHeader(name, value);
}
}
void addPathParam(String name, String value, boolean encoded) {
if (relativeUrl == null) {
// The relative URL is cleared when the first query parameter is set.
throw new AssertionError();
}
relativeUrl = relativeUrl.replace("{" + name + "}", canonicalizeForPath(value, encoded));
}
private static String canonicalizeForPath(String input, boolean alreadyEncoded) {
int codePoint;
for (int i = 0, limit = input.length(); i < limit; i += Character.charCount(codePoint)) {
codePoint = input.codePointAt(i);
if (codePoint < 0x20 || codePoint >= 0x7f
|| PATH_SEGMENT_ALWAYS_ENCODE_SET.indexOf(codePoint) != -1
|| (!alreadyEncoded && (codePoint == '/' || codePoint == '%'))) {
// Slow path: the character at i requires encoding!
Buffer out = new Buffer();
out.writeUtf8(input, 0, i);
canonicalizeForPath(out, input, i, limit, alreadyEncoded);
return out.readUtf8();
}
}
// Fast path: no characters required encoding.
return input;
}
private static void canonicalizeForPath(Buffer out, String input, int pos, int limit,
boolean alreadyEncoded) {
Buffer utf8Buffer = null; // Lazily allocated.
int codePoint;
for (int i = pos; i < limit; i += Character.charCount(codePoint)) {
codePoint = input.codePointAt(i);
if (alreadyEncoded
&& (codePoint == '\t' || codePoint == '\n' || codePoint == '\f' || codePoint == '\r')) {
// Skip this character.
} else if (codePoint < 0x20 || codePoint >= 0x7f
|| PATH_SEGMENT_ALWAYS_ENCODE_SET.indexOf(codePoint) != -1
|| (!alreadyEncoded && (codePoint == '/' || codePoint == '%'))) {
// Percent encode this character.
if (utf8Buffer == null) {
utf8Buffer = new Buffer();
}
utf8Buffer.writeUtf8CodePoint(codePoint);
while (!utf8Buffer.exhausted()) {
int b = utf8Buffer.readByte() & 0xff;
out.writeByte('%');
out.writeByte(HEX_DIGITS[(b >> 4) & 0xf]);
out.writeByte(HEX_DIGITS[b & 0xf]);
}
} else {
// This character doesn't need encoding. Just copy it over.
out.writeUtf8CodePoint(codePoint);
}
}
}
void addQueryParam(String name, String value, boolean encoded) {
if (relativeUrl != null) {
// Do a one-time combination of the built relative URL and the base URL.
urlBuilder = baseUrl.newBuilder(relativeUrl);
if (urlBuilder == null) {
throw new IllegalArgumentException(
"Malformed URL. Base: " + baseUrl + ", Relative: " + relativeUrl);
}
relativeUrl = null;
}
if (encoded) {
urlBuilder.addEncodedQueryParameter(name, value);
} else {
urlBuilder.addQueryParameter(name, value);
}
}
void addFormField(String name, String value, boolean encoded) {
if (encoded) {
formBuilder.addEncoded(name, value);
} else {
formBuilder.add(name, value);
}
}
void addPart(Headers headers, RequestBody body) {
multipartBuilder.addPart(headers, body);
}
void addPart(MultipartBody.Part part) {
multipartBuilder.addPart(part);
}
void setBody(RequestBody body) {
this.body = body;
}
Request build() {
HttpUrl url;
HttpUrl.Builder urlBuilder = this.urlBuilder;
if (urlBuilder != null) {
url = urlBuilder.build();
} else {
// No query parameters triggered builder creation, just combine the relative URL and base URL.
url = baseUrl.resolve(relativeUrl);
if (url == null) {
throw new IllegalArgumentException(
"Malformed URL. Base: " + baseUrl + ", Relative: " + relativeUrl);
}
}
RequestBody body = this.body;
if (body == null) {
// Try to pull from one of the builders.
if (formBuilder != null) {
body = formBuilder.build();
} else if (multipartBuilder != null) {
body = multipartBuilder.build();
} else if (hasBody) {
// Body is absent, make an empty body.
body = RequestBody.create(null, new byte[0]);
}
}
MediaType contentType = this.contentType;
if (contentType != null) {
if (body != null) {
body = new ContentTypeOverridingRequestBody(body, contentType);
} else {
requestBuilder.addHeader("Content-Type", contentType.toString());
}
}
//生成一个Request对象
return requestBuilder
.url(url)
.method(method, body)
.build();
}
private static class ContentTypeOverridingRequestBody extends RequestBody {
private final RequestBody delegate;
private final MediaType contentType;
ContentTypeOverridingRequestBody(RequestBody delegate, MediaType contentType) {
this.delegate = delegate;
this.contentType = contentType;
}
@Override public MediaType contentType() {
return contentType;
}
@Override public long contentLength() throws IOException {
return delegate.contentLength();
}
@Override public void writeTo(BufferedSink sink) throws IOException {
delegate.writeTo(sink);
}
}
}OkHttpCall
OkHttpCall okHttpCall = new OkHttpCall<>(serviceMethod, args);在创建了ServiceMethod对象后，使用该ServiceMethod对象和其参数创建一个OKHttPCall对象
OkHttpCall okHttpCall = new OkHttpCall<>(serviceMethod, args);在合适的时候调用ServiceMethod对象的toRequest方法生成一个Request对象，toReques()的内部实现就是调用RequestBuilder对象的build方法。
/** Builds an HTTP request from method arguments. */
Request toRequest(Object... args) throws IOException {
RequestBuilder requestBuilder = new RequestBuilder(httpMethod, baseUrl, relativeUrl, headers,
contentType, hasBody, isFormEncoded, isMultipart);
@SuppressWarnings("unchecked") // It is an error to invoke a method with the wrong arg types.
ParameterHandler<Object>[] handlers = (ParameterHandler<Object>[]) parameterHandlers;
int argumentCount = args != null ? args.length : 0;
if (argumentCount != handlers.length) {
throw new IllegalArgumentException("Argument count (" + argumentCount
+ ") doesn't match expected count (" + handlers.length + ")");
}
for (int p = 0; p < argumentCount; p++) {
handlers[p].apply(requestBuilder, args[p]);
}
return requestBuilder.build();
}OkHttpCall 实现了Call接口，这个Call接口和OkHttp中的Call接口一样，毕竟一家公司嘛。
其实就是对OkHttpCall 做了一层包装。
最后方法的执行时通过调用
return serviceMethod.callAdapter.adapt(okHttpCall);
返回接口中方法定义的返回值。
这块的流程就是构造一个OKHttp对象需要使用ServiceMethod对象和相应的参数。
OkHttpCall okHttpCall = new OkHttpCall<>(serviceMethod, args);最后创建具体的Call对象时
private okhttp3.Call createRawCall() throws IOException {
Request request = serviceMethod.toRequest(args);
okhttp3.Call call = serviceMethod.callFactory.newCall(request);
if (call == null) {
throw new NullPointerException("Call.Factory returned null.");
}
return call;
}调用了ServiceMethod对象的toRequest方法，然后使用这个request对象创建了一个Call对象。
/** Builds an HTTP request from method arguments. */
Request toRequest(Object... args) throws IOException {
RequestBuilder requestBuilder = new RequestBuilder(httpMethod, baseUrl, relativeUrl, headers,
contentType, hasBody, isFormEncoded, isMultipart);
@SuppressWarnings("unchecked") // It is an error to invoke a method with the wrong arg types.
ParameterHandler<Object>[] handlers = (ParameterHandler<Object>[]) parameterHandlers;
int argumentCount = args != null ? args.length : 0;
if (argumentCount != handlers.length) {
throw new IllegalArgumentException("Argument count (" + argumentCount
+ ") doesn't match expected count (" + handlers.length + ")");
}
for (int p = 0; p < argumentCount; p++) {
handlers[p].apply(requestBuilder, args[p]);
}
//生成一个Request对象
return requestBuilder.build();
}
android
java
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