前言
spring提供了丰富的注解，但有时并不能满足现有业务复杂的需求，我们可以通过自定义注解完善我们的业务框架。
寄语：
孰能生巧，天道酬勤，是走向成功的必经之路。
注解创建说明
@Target
@Target –注解用于什么地方，默认值为任何元素，表示该注解用于什么地方。可用的ElementType指定参数
● ElementType.CONSTRUCTOR:用于描述构造器
● ElementType.FIELD:成员变量、对象、属性（包括enum实例）
● ElementType.LOCAL_VARIABLE:用于描述局部变量
● ElementType.METHOD:用于描述方法
● ElementType.PACKAGE:用于描述包
● ElementType.PARAMETER:用于描述参数
● ElementType.TYPE:用于描述类、接口(包括注解类型) 或enum声明
@Retention
表示需要在什么级别保存该注解信息。
什么时候使用该注解，即注解的生命周期，使用RetentionPolicy来指定
● RetentionPolicy.SOURCE : 在编译阶段丢弃。这些注解在编译结束之后就不再有任何意义，所以它们 不会写入字节码。@Override, @SuppressWarnings都属于这类注解。
● RetentionPolicy.CLASS : 在类加载的时候丢弃。在字节码文件的处理中有用。注解默认使用这种方式
● RetentionPolicy.RUNTIME : 始终不会丢弃，运行期也保留该注解，因此可以使用反射机制读取该注解的信息。我们自定义的注解通常使用这种方式。
@Document
将注解包含在Javadoc中
@Inherited
允许子类继承父类中的注解
实例说明
OperationType.java
`package com.basic.bl.rest.demo.aop;
public enum OperationType {
/**
* 操作类型
*/
UNKNOWN("unknown"),
DELETE("delete"),
SELECT("select"),
UPDATE("update"),
INSERT("insert");
private String value;
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
OperationType(String s) {
this.value = s;
}}`
OperationUnit.java
`package com.basic.bl.rest.demo.aop;
public enum OperationUnit {
/**
* 被操作的单元
*/
UNKNOWN("unknown"),
USER("user"),
EMPLOYEE("employee"),
SELLER("seller");
private String value;
OperationUnit(String value) {
this.value = value;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}}
`
OperationLog.java
`package com.basic.bl.rest.demo.aop;
import java.util.Date;
public class OperationLog {
private String id;
private Date createTime;
/**
* 日志等级
*/
private Integer level;
/**
* 被操作的对象
*/
private String operationUnit;
/**
* 方法名
*/
private String method;
/**
* 参数
*/
private String args;
/**
* 操作人id
*/
private String userId;
/**
* 操作人
*/
private String userName;
/**
* 日志描述
*/
private String describe;
/**
* 操作类型
*/
private String operationType;
/**
* 方法运行时间
*/
private Long runTime;
/**
* 方法返回值
*/
private String returnValue;
@Override
public String toString() {
return "OperationLog{" +
"id='" + id + '\'' +
", createTime=" + createTime +
", level=" + level +
", operationUnit='" + operationUnit + '\'' +
", method='" + method + '\'' +
", args='" + args + '\'' +
", userId='" + userId + '\'' +
", userName='" + userName + '\'' +
", describe='" + describe + '\'' +
", operationType='" + operationType + '\'' +
", runTime=" + runTime +
", returnValue='" + returnValue + '\'' +
'}';
}
public Long getRunTime() {
return runTime;
}
public void setRunTime(Long runTime) {
this.runTime = runTime;
}
public String getReturnValue() {
return returnValue;
}
public void setReturnValue(String returnValue) {
this.returnValue = returnValue;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
public Integer getLevel() {
return level;
}
public void setLevel(Integer level) {
this.level = level;
}
public String getOperationUnit() {
return operationUnit;
}
public void setOperationUnit(String operationUnit) {
this.operationUnit = operationUnit;
}
public String getMethod() {
return method;
}
public void setMethod(String method) {
this.method = method;
}
public String getArgs() {
return args;
}
public void setArgs(String args) {
this.args = args;
}
public String getUserId() {
return userId;
}
public void setUserId(String userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getDescribe() {
return describe;
}
public void setDescribe(String describe) {
this.describe = describe;
}
public String getOperationType() {
return operationType;
}
public void setOperationType(String operationType) {
this.operationType = operationType;
}}
`
OperationLogDetail.java
`package com.basic.bl.rest.demo.aop;
import java.lang.annotation.*;
//@OperationLogDetail(detail = "通过手机号[{{tel}}]获取用户名",level = 3,operationUnit = OperationUnit.USER,operationType = OperationType.SELECT)
@Documented
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface OperationLogDetail {
/**
* 方法描述,可使用占位符获取参数:{{tel}}
*/
String detail() default "";
/**
* 日志等级:自己定，此处分为1-9
*/
int level() default 0;
/**
* 操作类型(enum):主要是select,insert,update,delete
*/
OperationType operationType() default OperationType.UNKNOWN;
/**
* 被操作的对象(此处使用enum):可以是任何对象，如表名(user)，或者是工具(redis)
*/
OperationUnit operationUnit() default OperationUnit.UNKNOWN;}
`
LogAspect.java
`package com.basic.bl.rest.demo.aop;
import com.alibaba.fastjson.JSON;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
@Aspect
@Component
public class LogAspect {
/**
* 此处的切点是注解的方式，也可以用包名的方式达到相同的效果
* '@Pointcut("execution(* com.basic.bl.rest.demo.aop.service.impl.*.*(..))")'
*/
@Pointcut("@annotation(com.basic.bl.rest.demo.aop.OperationLogDetail)")
public void operationLog(){}
/**
* 环绕增强，相当于MethodInterceptor
*/
@Around("operationLog()")
public Object doAround(ProceedingJoinPoint joinPoint) throws Throwable {
Object res = null;
long time = System.currentTimeMillis();
try {
res = joinPoint.proceed();
time = System.currentTimeMillis() - time;
return res;
} finally {
try {
//方法执行完成后增加日志
addOperationLog(joinPoint,res,time);
}catch (Exception e){
System.out.println("LogAspect 操作失败：" + e.getMessage());
e.printStackTrace();
}
}
}
private void addOperationLog(JoinPoint joinPoint, Object res, long time){
MethodSignature signature = (MethodSignature)joinPoint.getSignature();
OperationLog operationLog = new OperationLog();
operationLog.setRunTime(time);
operationLog.setReturnValue(JSON.toJSONString(res));
operationLog.setId(UUID.randomUUID().toString());
operationLog.setArgs(JSON.toJSONString(joinPoint.getArgs()));
operationLog.setCreateTime(new Date());
operationLog.setMethod(signature.getDeclaringTypeName() + "." + signature.getName());
operationLog.setUserId("#{currentUserId}");
operationLog.setUserName("#{currentUserName}");
OperationLogDetail annotation = signature.getMethod().getAnnotation(OperationLogDetail.class);
if(annotation != null){
operationLog.setLevel(annotation.level());
operationLog.setDescribe(getDetail(((MethodSignature)joinPoint.getSignature()).getParameterNames(),joinPoint.getArgs(),annotation));
operationLog.setOperationType(annotation.operationType().getValue());
operationLog.setOperationUnit(annotation.operationUnit().getValue());
}
//TODO 这里保存日志
System.out.println("记录日志:" + operationLog.toString());// operationLogService.insert(operationLog);
}
/**
* 对当前登录用户和占位符处理
* @param argNames 方法参数名称数组
* @param args 方法参数数组
* @param annotation 注解信息
* @return 返回处理后的描述
*/
private String getDetail(String[] argNames, Object[] args, OperationLogDetail annotation){
Map<Object, Object> map = new HashMap<>(4);
for(int i = 0;i < argNames.length;i++){
map.put(argNames[i],args[i]);
}
String detail = annotation.detail();
try {
detail = "'" + "#{currentUserName}" + "'=》" + annotation.detail();
for (Map.Entry<Object, Object> entry : map.entrySet()) {
Object k = entry.getKey();
Object v = entry.getValue();
detail = detail.replace("{{" + k + "}}", JSON.toJSONString(v));
}
}catch (Exception e){
e.printStackTrace();
}
return detail;
}
@Before("operationLog()")
public void doBeforeAdvice(JoinPoint joinPoint){
System.out.println("进入方法前执行.....");
}
/**
* 处理完请求，返回内容
* @param ret
*/
@AfterReturning(returning = "ret", pointcut = "operationLog()")
public void doAfterReturning(Object ret) {
System.out.println("方法的返回值 : " + ret);
}
/**
* 后置异常通知
*/
@AfterThrowing("operationLog()")
public void throwss(JoinPoint jp){
System.out.println("方法异常时执行.....");
}
/**
* 后置最终通知,final增强，不管是抛出异常或者正常退出都会执行
*/
@After("operationLog()")
public void after(JoinPoint jp){
System.out.println("方法最后执行.....");
}}`
DemoController.java
`package com.basic.bl.rest.demo.aop;
import com.basic.bl.rest.demo.aop.service.DemoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
@RequestMapping("demo")
public class DemoController {
@Autowired
private DemoService demoService;
/**
* 访问路径 http://localhost:11000/user/findUserNameByTel?tel=1234567
* @param tel 手机号
* @return userName
*/
@ResponseBody
@RequestMapping("/findUserNameByTel")
public String findUserNameByTel(@RequestParam("tel") String tel){
return demoService.findUserName(tel);
}}
``
DemoServiceImpl.java
`package com.basic.bl.rest.demo.aop.service.impl;
import com.basic.bl.rest.demo.aop.OperationLogDetail;
import com.basic.bl.rest.demo.aop.OperationType;
import com.basic.bl.rest.demo.aop.OperationUnit;
import com.basic.bl.rest.demo.aop.service.DemoService;
import org.springframework.stereotype.Service;
@Service
public class DemoServiceImpl implements DemoService {
@OperationLogDetail(detail = "通过手机号[{{tel}}]获取用户名",level = 3,operationUnit = OperationUnit.USER,operationType = OperationType.SELECT)
@Override
public String findUserName(String tel) {
System.out.println("tel:" + tel);
return "zhangsan";
}}`
DemoService.java
`package com.basic.bl.rest.demo.aop.service;
public interface DemoService {
/**
* 获取用户信息
* @return
* @param tel
*/
String findUserName(String tel);}
`
结果
进入方法前执行.....
tel:1721212121
记录日志:OperationLog{id='b8dc5682-0c68-4efb-9841-8a929dc91663', createTime=Tue Dec 03 00:45:26 CST 2019, level=3, operationUnit='user', method='com.basic.bl.rest.demo.aop.service.impl.DemoServiceImpl.findUserName', args='["1721212121"]', userId='#{currentUserId}', userName='#{currentUserName}', describe=''#{currentUserName}'=》通过手机号["1721212121"]获取用户名', operationType='select', runTime=5, returnValue='"zhangsan"'}
方法最后执行.....
方法的返回值 : zhangsan
java
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