Spring MVC中@JsonView的使用

一、@JsonView注解的简介

@JsonView是jackson json中的一个注解，Spring webmvc也支持这个注解，它的作用就是控制输入输出后的json

二、@JsonView注解的使用步骤

1.使用接口来声明多个视图

package com.knyel.dto;

public class User {

    public interface UserSimpleView {};
    public interface UserDetailView extends UserSimpleView {};

    private String username;
    private  String password;

    public String getUsername (){
        return username;
    }

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

    public String getPassword (){
        return password;
    }

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

    @Override
    public String toString (){
        return "User{" + "username='" + username + '\'' + ", password='" + password + '\'' + '}';
    }
}

2.在值对象的get方法上指定视图

package com.knyel.dto;

import com.fasterxml.jackson.annotation.JsonView;

public class User {

    public interface UserSimpleView {};
    public interface UserDetailView extends UserSimpleView {};

    private String username;
    private  String password;
    @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;
    }

    @Override
    public String toString (){
        return "User{" + "username='" + username + '\'' + ", password='" + password + '\'' + '}';
    }
}

3.在controller方法上指定视图

package com.knyel.wb.controller;

import com.fasterxml.jackson.annotation.JsonView;
import com.knyel.dto.User;
import com.knyel.dto.UserQueryCondition;
import org.springframework.data.web.PageableDefault;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.data.domain.Pageable;

import java.util.ArrayList;
import java.util.List;

@RestController
public class UserController {
    @RequestMapping(value = "/user",method = RequestMethod.GET)
    @JsonView(User.UserSimpleView.class)
    public List<User> query(UserQueryCondition userQueryCondition, @PageableDefault(page=1,size=10,sort="username,asc") Pageable pageable){
        System.out.println(pageable.getPageNumber());
        System.out.println(pageable.getSort());
        System.out.println(pageable.getPageSize());
        System.out.println(userQueryCondition.toString());
        List<User> users=new ArrayList<>();
        users.add(new User());
        users.add(new User());
        users.add(new User());
        return  users;
    }
    @RequestMapping(value="/user/{id:\\d+}",method = RequestMethod.GET)
    @JsonView(User.UserDetailView.class)
    public User getInfo(@PathVariable String id){
        User user=new User();
        user.setUsername("knyel");
        System.out.println(user);
        return user;
    }
}

4.测试类

package com.knyel.controller;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.MediaType;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.result.MockMvcResultMatchers;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserControllerTest {
    @Autowired
    private WebApplicationContext wac;

    private MockMvc mockMvc;

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

    @Test
    public void whenQuerySuccess () throws Exception{
        String result=mockMvc.perform(MockMvcRequestBuilders.get("/user")
                .param("username","knyel")
                .param("age","18")
                .param("ageTo","60")
                .param("phone","110")
                .param("size","15")
                .param("page","2")
                .param("sort","age,desc")
                .contentType(MediaType.APPLICATION_JSON_UTF8))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andExpect(MockMvcResultMatchers.jsonPath("$.length()").value("3"))//查询的根元素，例如$.length()代表整个传过来的json的文档
                .andReturn().getResponse().getContentAsString();
        System.out.println(result);
    }

    @Test
    public void whenGenInfoSuccess() throws Exception{
        String result=mockMvc.perform(MockMvcRequestBuilders.get("/user/1")
        .contentType(MediaType.APPLICATION_JSON_UTF8))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andExpect(MockMvcResultMatchers.jsonPath("$.username").value("knyel"))
                .andReturn().getResponse().getContentAsString();
        System.out.println(result);
    }

    @Test
    public void whenGetInfoFail() throws Exception{
        mockMvc.perform(MockMvcRequestBuilders.get("/user/a")
        .contentType(MediaType.APPLICATION_JSON_UTF8))
                .andExpect(MockMvcResultMatchers.status().is4xxClientError());
    }
}

whenQuerySuccess的返回值为：

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

whenGetInfoSuccess的返回值为：

{"username":"knyel","password":null}

对于带有分页查询的例子

　　@Test
    public void whenGetDwbzxxSuccess() throws Exception{

        String result=mockMvc.perform(MockMvcRequestBuilders.get("/dwbzxx/findDwbzxx")
                .param("limit", "10")
                .param("offset", "0")
                .param("dwdmYj", "1399")
                .param("dwdmEj", "28e516432383411b8fac66a2b8ff08bf")
                .contentType(MediaType.APPLICATION_JSON))
                .andReturn().getResponse().getContentAsString();

        System.out.println(result);
    }