第九篇 - SpringBoot统一结果封装Json数据

前面几节学习了SpringBoot和Vue的结合，以及Vue跳转到另一个Vue页面。这节学习SpringBoot controller返回Json数据格式封装。

参考链接：https://zhuanlan.zhihu.com/p/347233348

第一步：在entity文件夹下新建一个ResultVo类。

ResultVo.java

package com.example.demo.entity;

public class ResultVo {
    //相应码
    private Integer code;
    //信息
    private String message;
    //返回数据
    private Object data;

    public ResultVo(Integer Code, String Message, Object Data){
        this.code = Code;
        this.message = Message;
        this.data = Data;
    }
}

View Code

第二步：修改User.java

package com.example.demo.entity;

public class User {
    public String user_account;
    public String user_password;

    public User(String User_account, String User_password){
        this.user_account = User_account;
        this.user_password = User_password;
    }
}

View Code

第三步：新建LoginVo.java

package com.example.demo.entity;

import java.io.Serializable;

public class LoginVo implements Serializable {
    private  User user;
    public LoginVo(User user_obj){
        this.user = user_obj;
    }
}

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第四步：修改UserController.java的/login

package com.example.demo.controller;

import com.example.demo.entity.LoginVo;
import com.example.demo.entity.User;
import com.example.demo.entity.ResultVo;
import com.example.demo.service.impl.UserServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import javax.servlet.http.HttpServletRequest;
import java.util.List;

@RestController
@RequestMapping("/api")
@CrossOrigin(origins = "http://localhost:8080")
public class UserController {
    @Autowired
    private UserServiceImpl userServer;

    @GetMapping("/users")
    public List<User> getUserList()
    {
        return userServer.getUserList();
    }

    @PostMapping("/login")
    @ResponseBody
    public ResultVo loginStatus(HttpServletRequest req)
    {
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        System.out.println(username);
        System.out.println(password);
        List<User> userlist = userServer.getUserList();
        for (User us: userlist){
            if (us.user_account.equals(username) && us.user_password.equals(password)){
                return new ResultVo(200, "登录成功", new LoginVo(us));
            }
        }
        return new ResultVo(201, "用户名/密码错误", "");
    }
}

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第五步：用postman测试接口

/user接口可以正常访问，在来试试我们刚修改的/login

报错了，后端显示的错误是Resolved [org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation]

参考链接：https://stackoverflow.com/questions/28466207/could-not-find-acceptable-representation-using-spring-boot-starter-web

原因在于没有给ResultVo写get函数，因此修改ResultVo.java

package com.example.demo.entity;

public class ResultVo {
    //相应码
    private Integer code;
    //信息
    private String message;
    //返回数据
    private Object data;

    public Integer getCode(){
        return this.code;
    }

    public String getMessage(){
        return this.message;
    }

    public Object getData(){
        return this.data;
    }

    public ResultVo(Integer Code, String Message, Object Data){
        this.code = Code;
        this.message = Message;
        this.data = Data;
    }

}

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再次用postman测试

可以看到成功输出我们想要的报错信息了，然后试试用户名密码正确的情况

现在应该可以猜到为什么报错了吗？没错，因为LoginVo.java和User.java里面也要添加get函数啊

LoginVo.java

package com.example.demo.entity;

import java.io.Serializable;

public class LoginVo implements Serializable {
    private  User user;

    public User getUser(){
        return this.user;
    }
    public LoginVo(User user_obj){
        this.user = user_obj;
    }
}

View Code

User.java

package com.example.demo.entity;

public class User {
    public String user_account;
    public String user_password;

    public String getUser_account(){
        return this.user_account;
    }

    public String getUser_password(){
        return this.user_password;
    }

    public User(String User_account, String User_password){
        this.user_account = User_account;
        this.user_password = User_password;
    }
}