【从零入门系列-4】Spring Boot 之 WEB接口设计实现

文章系列


前言

前一章简述了已经实现了对数据库的增删改查以及复杂查询的功能,这一步将对相应的功能方法封装成WEB接口,对外提供WEB接口服务。


控制层类设计及测试

控制层的角色是负责对访问路由到处理过程的关联映射和封装,在这里我们队Book新建一个控制类即可,在文件夹Controller上右键,New->Java Class新建BookController类。作为控制类,该类需要使用@Controller注解使之能够被识别为控制类对象,在这里我们使用@RestController,该注解包含了@Controller,相当于@Controller+@ResponseBody两个注解的结合,适合返回Json格式的控制器使用。

类定义

@RestController
@RequestMapping(path = "/library")
public class BookController {
    @Autowired
    private BookJpaRepository bookJpaRepository;

    @Autowired
    private BookService bookService;
}

考虑到数据库的操作需要用到BookJpaRepositoryBookService,这里首先声明这两个属性,并使用@Autowired注解自动装配。

在类上使用@RequestMapping(path = "/library")注解后,定义了该类的路径都是/library开始,可以统一接口路径,避免重复书写。

新增接口

/**
* 新增书籍
* @param name
* @param author
* @param image
* @return
*/
@PostMapping("/save")
public Map<String, Object> save(@RequestParam String name, @RequestParam String author, @RequestParam String image){
   Book book = new Book();
   Map<String, Object> rsp = new HashMap<>();
   book.setName(name);
   book.setAuthor(author);
   book.setImage(image);
   bookJpaRepository.save(book);
   rsp.put("data", book);
   rsp.put("code", "0");
   rsp.put("info", "成功");
   return rsp;
}

使用@PostMapping表示接口只接受POST请求,WEB接口路径为/library/save,该接口返回的是一个Map类型对象,但是由于类使用@RestController注解后,使得返回结果会自动转换成Json字符串格式。

接口参数@RequestParam的注解用于将指定的请求参数赋值给方法中的形参,默认根据参数名匹配,也可以使用value指定参数名,支持的参数如下:

  • name:形参绑定的请求参数名,与value功能一样,默认与形参名相同自动关联
  • required:指定该参数是否必输,默认为True
  • defaultValue:指定该参数的默认值
  • value:与name功能相同

在该接口中,通过形参自动绑定取的入参,然后通过BookJpaRepository直接save保存新增数据,save新增后,该记录自动生成的id值已经被设置到book变量。

为了接口通用,返回值增加了字段codeinfo分别用来返回错误码和错误信息,返回数据放在字段data

单元测试代码

@Autowired
private WebApplicationContext wac;

private MockMvc mockMvc;

@Before
public void setUp (){
    mockMvc = MockMvcBuilders.webAppContextSetup(wac).build();
}

引入Web的MVC单元测试对象,然后编写Web新增接口测试用例:

@Test
public void webApi(){
    try {
        String urlRoot = "/library";
        String urlApi = urlRoot + "/view/1";
        MvcResult mvcResult = mockMvc.perform(MockMvcRequestBuilders.get(urlApi)
                .contentType(MediaType.APPLICATION_JSON_UTF8))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andReturn();
        System.out.println("WEB测试返回[" + urlApi + "]:" + mvcResult.getResponse().getContentAsString());

    } catch (Exception e) {
        e.printStackTrace();
    }
}

执行结果:

1557907574221

删除接口

根据数据ID删除书籍,且数据id作为请求路径的一部分,不通过@RequestParam获取,而是通过@PathVariable("id"),代码如下:

/**
 * 删除书籍
 * @param id
 * @return
 */
@GetMapping("/remove/{id}")
public Map<String, Object> removeById(@PathVariable("id") Integer id){
    Map<String, Object> rsp = new HashMap<>();
    Optional<Book> book = bookJpaRepository.findById(id);
    if(!book.isPresent()) {
        rsp.put("code", 1001);
        rsp.put("info", "书籍ID[" + id + "]不存在");
    }else {
        bookJpaRepository.deleteById(id);
        rsp.put("code", 0);
        rsp.put("info", "书籍ID[" + id + "]删除成功");
        rsp.put("data", book);
    }
    return rsp;
}

@PathVariable只支持一个属性value,类型是为String,代表绑定的属性名称,默认绑定为同名的形参。

在接口中,我们使用@GetMapping接收处理GET请求,如果成功返回书籍信息,否则返回错误信息。

使用浏览器测试结果如下:

1557907999084
删除不存在的书籍时

1557908059948
正常删除数据

更新接口

根据书籍ID更新书籍信息,参数信息使用HttpServletRequest和路径参数相配合

/**
 * 更新书籍
 * @param id
 * @param request
 * @return
 */
@PostMapping("/edit/{id}")
public Map<String, Object> updateById(@PathVariable("id") Integer id, HttpServletRequest request){
    Map<String, Object> rsp = new HashMap<>();
    Optional<Book> book = bookJpaRepository.findById(id);
    if(!book.isPresent()) {
        rsp.put("code", 1001);
        rsp.put("info", "书籍ID[" + id + "]不存在");
    }else {
        Book bookUpd = book.get();
        if(request.getParameter("name") != null){
            bookUpd.setName(request.getParameter("name"));
        }
        if(request.getParameter("author") != null){
            bookUpd.setAuthor(request.getParameter("author"));
        }
        if(request.getParameter("image") != null){
            bookUpd.setImage(request.getParameter("image"));
        }
        rsp.put("code", 0);
        rsp.put("info", "书籍ID[" + id + "]更新成功");
        rsp.put("data", bookUpd);
    }
    return rsp;
}

HttpServletRequest对象代表客户端的请求,当客户端通过HTTP协议访问服务器时,HTTP请求头中的所有信息都封装在这个对象中,通过这个对象提供的方法,可以获得客户端请求的所有信息。

单元测试用例:

@Test
public void webBookEdit() throws Exception {
    String url = "/library/edit/2";
    // 只修改名字
    MvcResult mvcResult = mockMvc.perform(MockMvcRequestBuilders.post(url)
            .param("name", "webBookEdit1")
            .contentType(MediaType.APPLICATION_JSON_UTF8))
            .andExpect(MockMvcResultMatchers.status().isOk())
            .andReturn();
    System.out.println("1-WEB测试返回[" + url + "]:" + mvcResult.getResponse().getContentAsString());

    // 修改名字和作者
    mvcResult = mockMvc.perform(MockMvcRequestBuilders.post(url)
            .param("name", "webBookEdit2")
            .param("author", "webBookEdit2")
            .contentType(MediaType.APPLICATION_JSON_UTF8))
            .andExpect(MockMvcResultMatchers.status().isOk())
            .andReturn();
    System.out.println("2-WEB测试返回[" + url + "]:" + mvcResult.getResponse().getContentAsString());
}

执行结果(JSON格式化处理过)

Hibernate: select book0_.id as id1_0_0_, book0_.author as author2_0_0_, book0_.image as image3_0_0_, book0_.name as name4_0_0_ from library_book book0_ where book0_.id=?
1-WEB测试返回[/library/edit / 2]: 
{
    "code": 0,
    "data": {
        "id": 2,
        "name": "webBookEdit1",
        "author": "arbboter",
        "image": "https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=2656353677,2997395625&fm=26&gp=0.jpg"
    },
    "info": "书籍ID[2]更新成功"
}
Hibernate: select book0_.id as id1_0_0_, book0_.author as author2_0_0_, book0_.image as image3_0_0_, book0_.name as name4_0_0_ from library_book book0_ where book0_.id=?
2-WEB测试返回[/library/edit/2]:
{
    "code": 0,
    "data": {
        "id": 2,
        "name": "webBookEdit2",
        "author": "webBookEdit2",
        "image": "https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=2656353677,2997395625&fm=26&gp=0.jpg"
    },
    "info": "书籍ID[2]更新成功"
}

从上述执行结果我们可以看到,在使用JpaRepositorysave更新数据时,只会更新非null字段,且返回结果包括完整的更新后的数据内容,即默认支持按设定的字段更新,而不是每次需要全字段更新。

查询接口

使用路径参数根据书籍ID获取书籍内容信息,代码如下:

/**
 * 查看书籍
 * @param id
 * @return
 */
@GetMapping("/view/{id}")
public Map<String, Object> findById(@PathVariable("id") Integer id){
    Map<String, Object> rsp = new HashMap<>();
    Optional<Book> book = bookJpaRepository.findById(id);
    if(!book.isPresent()) {
        rsp.put("code", 1001);
        rsp.put("info", "书籍ID[" + id + "]不存在");
    }else {
        rsp.put("code", 0);
        rsp.put("info", "成功");
        rsp.put("data", book);
    }
    return rsp;
}

测试执行结果如下:

1557909406789

搜索接口

由于我们之前的搜索接口的入参类型为Map,但是Web接口的入参信息都是从HttpServletRequest获取,因此首先需要将需要的入参信息从HttpServletRequest转换到Map类型,然再使用。考虑到该转换功能为通用型,因此可以将该函数封装到系统的工具包下面,新建Util包,然后右键新建Util文件,完成数据的转换函数,代码如下:

public class Util {
    /**
     * 把 @HttpServletRequest 转换成普通的字典
     * @param request
     * @return
     */
    public static Map getParameterMap(HttpServletRequest request) {
        // 参数Map
        Map properties = request.getParameterMap();
        // 返回值Map
        Map returnMap = new HashMap();
        Iterator entries = properties.entrySet().iterator();
        Map.Entry entry;
        String name = "";
        String value = "";
        while (entries.hasNext()) {
            entry = (Map.Entry) entries.next();
            name = (String) entry.getKey();
            Object valueObj = entry.getValue();
            if(null == valueObj){
                value = "";
            }else if(valueObj instanceof String[]){
                String[] values = (String[])valueObj;
                for(int i=0;i<values.length;i++){
                    value = values[i] + ",";
                }
                value = value.substring(0, value.length()-1);
            }else{
                value = valueObj.toString();
            }
            returnMap.put(name, value);
        }
        return returnMap;
    }
}

然后使用我们BookService实现的封装的复杂查询接口即可,代码如下:

/**
 * 搜索查询接口
 * @param request
 * @return
 */
@PostMapping("/search")
public Map<String, Object> search(HttpServletRequest request){
    Map<String, String> map = new HashMap<>();
    map = Util.getParameterMap(request);
    Page<Book> books = bookService.search(map);

    Map<String, Object> rsp = new HashMap<>();
    rsp.put("code", 0);
    rsp.put("info", "成功");
    rsp.put("rows", books.getContent());
    rsp.put("total", books.getTotalElements());
    return rsp;
}

此处返回rowstotal是为了后续Web页面的bootstrap-table需要,该控件根据这两个数据以表格化的形式展示查询结果数据。

由于此处使用POST请求类型,测试时依旧使用MockMvcWebApplicationContext,测试代码如下:

@Test
public void webSearch() throws Exception{
    String url = "/library/search";
    // 1-无条件
    MvcResult mvcResult = mockMvc.perform(MockMvcRequestBuilders.post(url)
            .contentType(MediaType.APPLICATION_JSON_UTF8))
            .andExpect(MockMvcResultMatchers.status().isOk())
            .andReturn();
    System.out.println("1-无条件-WEB测试返回[" + url + "]:" + mvcResult.getResponse().getContentAsString());

    // 2-根据作者名查询
    mvcResult = mockMvc.perform(MockMvcRequestBuilders.post(url)
            .param("author", "作者_3")
            .contentType(MediaType.APPLICATION_JSON_UTF8))
            .andExpect(MockMvcResultMatchers.status().isOk())
            .andReturn();
    System.out.println("2-根据作者名(作者_3)查询-WEB测试返回[" + url + "]:" + mvcResult.getResponse().getContentAsString());
}

测试执行结果如下:

Hibernate: select TOP(?) book0_.id as id1_0_, book0_.author as author2_0_, book0_.image as image3_0_, book0_.name as name4_0_ from library_book book0_ where 1=1 order by book0_.id desc
Hibernate: select count(book0_.id) as col_0_0_ from library_book book0_ where 1=1
1-无条件-WEB测试返回[/library/search]:
{
    "total": 22,
    "code": 0,
    "rows": [{
            "id": 26,
            "name": "书名_19",
            "author": "作者_4",
            "image": "img19"
        }, {
            "id": 25,
            "name": "书名_18",
            "author": "作者_3",
            "image": "img18"
        }, {
            "id": 24,
            "name": "书名_17",
            "author": "作者_2",
            "image": "img17"
        }, {
            "id": 23,
            "name": "书名_16",
            "author": "作者_1",
            "image": "img16"
        }, {
            "id": 22,
            "name": "书名_15",
            "author": "作者_0",
            "image": "img15"
        }, {
            "id": 21,
            "name": "书名_14",
            "author": "作者_4",
            "image": "img14"
        }, {
            "id": 20,
            "name": "书名_13",
            "author": "作者_3",
            "image": "img13"
        }, {
            "id": 19,
            "name": "书名_12",
            "author": "作者_2",
            "image": "img12"
        }, {
            "id": 18,
            "name": "书名_11",
            "author": "作者_1",
            "image": "img11"
        }, {
            "id": 17,
            "name": "书名_10",
            "author": "作者_0",
            "image": "img10"
        }
    ],
    "info": "成功"
}
Hibernate: select TOP(?) book0_.id as id1_0_, book0_.author as author2_0_, book0_.image as image3_0_, book0_.name as name4_0_ from library_book book0_ where book0_.author=? order by book0_.id desc
2-根据作者名(作者_3)查询-WEB测试返回[/library/search]:
{
    "total": 4,
    "code": 0,
    "rows": [{
            "id": 25,
            "name": "书名_18",
            "author": "作者_3",
            "image": "img18"
        }, {
            "id": 20,
            "name": "书名_13",
            "author": "作者_3",
            "image": "img13"
        }, {
            "id": 15,
            "name": "书名_8",
            "author": "作者_3",
            "image": "img8"
        }, {
            "id": 10,
            "name": "书名_3",
            "author": "作者_3",
            "image": "img3"
        }
    ],
    "info": "成功"
}

结束语

到这里,整个项目的所有服务器后端部分已经完成,已经可以提供给前端使用各种常用的Web接口,下一篇我们将从前端一起整合整个项目,实现数据的展示和管理,敬请期待。

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