@JsonView的使用

@JsonView的使用

注意是：com.fasterxml.jackson.annotation.JsonView

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
    <version>2.7.5</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.8</version>
</dependency>

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.9.8</version>
</dependency>

1.使用场景

在某一些请求返回的JSON中，我们并不希望返回pojo中的某些字段或全部字段。而在另一些请求中需要返回某些字段。

2.实现

2.1 @JsonView的使用步骤

• 1.使用接口来声明多个视图
• 2.在值对象的get方法上指定视图
• 3.在Controller的方法上指定视图

2.2 完整事例代码

2.2.1User对象定义

public class User{

    /**
     * 用户简单视图
     */
    public interface UserSimpleView{};

    /**
     * 用户详情视图
     */
    public interface UserDetailView extends UserSimpleView{};

    private String username;

    private String password;

    private String age;

    @JsonView(UserSimpleView.class)
    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    @JsonView(UserDetailView.class)
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @JsonView(UserSimpleView.class)
    public String getAge() {
        return age;
    }
    
    public void setAge(String age) {
        this.age = age;
    }
}

• 这里完成了步骤1和步骤2
• 定义了步骤1的两个视图接口UserSimpleView和UserDetailView,UserDetailView继承UserSimpleView，UserDetailView拥有视图UserSimpleView的属性
• 完成了步骤2的在相应的get方法上声明JsonView

2.2.2 定义UserController

@RestController
public class UserController {

    @GetMapping("/user")
    @JsonView({User.UserSimpleView.class})
    public List<User> query(UserQueryCondition userQueryCondition, @PageableDefault(size = 10,page=1,sort = {"username","age"},direction = Sort.Direction.DESC) Pageable pageable){
        System.out.println(userQueryCondition);
        System.out.print(pageable.getPageSize());
        System.out.println(pageable.getSort());
        System.out.println(pageable.getOffset());
        List<User> users = new ArrayList<>();
        users.add(new User());
        users.add(new User());
        users.add(new User());
        return users;
    }

    /**
     * 在url中使用正则表达式
     * @param id
     * @return
     */
    @GetMapping("/user/{id:\d+}")
    @JsonView(User.UserDetailView.class)
    public User get(@PathVariable String id){
        System.out.println(id);
        User user = new User();
        user.setUsername("tom");
        return user;
    }
}

• 完成步骤3，在不同Controller的方法上使用视图

2.2.3 测试

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserControllerTest {

    @Autowired
    private WebApplicationContext webApplicationContext;

    private MockMvc mockMvc;

    @Before
    public void setup(){

        //根据webApplicationContext构建mockMvc
        mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
    }

    @Test
    public void whenQuerySuccess() throws Exception {
        String result = mockMvc.perform(MockMvcRequestBuilders.get("/user")
                        .param("username","tom")
                        .param("age","11")
                        .param("ageTo","30")
                        .param("page","20")
                        .param("pageSize","100")
                        .param("sort","age,desc")
                        .contentType(MediaType.APPLICATION_JSON_UTF8))
                        .andExpect(MockMvcResultMatchers.status().isOk())
                        .andExpect(MockMvcResultMatchers.jsonPath("$.length()").value(3))
                        .andReturn().getResponse().getContentAsString();
        System.out.println(result);
    }

    /**
     * 请求成功逻辑测试
     * @throws Exception
     */
    @Test
    public void wherGetSuccess() throws Exception {
        String result = mockMvc.perform(MockMvcRequestBuilders.get("/user/1")
                        .contentType(MediaType.APPLICATION_JSON_UTF8))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andExpect(MockMvcResultMatchers.jsonPath("$.username").value("tom"))
                .andReturn().getResponse().getContentAsString();
        System.out.println(result);
    }

    /**
     * 路径正则表达式的匹配规则测试
     * @throws Exception
     */
    @Test
    public void whenGetFail() throws Exception {
        mockMvc.perform(MockMvcRequestBuilders.get("/user/a")
                        .contentType(MediaType.APPLICATION_JSON_UTF8))
                .andExpect(MockMvcResultMatchers.status().is4xxClientError());
    }


}

• 测试结果
• 查询全部的返回结果没有password字段

[{"username":null,"age":null},{"username":null,"age":null},{"username":null,"age":null}]

• 查询详情的返回结果有password字段

{"username":"tom","password":null,"age":null}