标准化后端向前端传来的Json数据

后端响应固定格式给前端：

1，创建一个专门存储数据的类；分别存储响应状态码code，响应数据，传输的消息。

public class CommonData {
    int code;
    Object data;
    String message;
 
    public CommonData(int code, String message) {
        this.code = code;
        this.message = message;
    }
 
    public CommonData(int code, Object data, String message) {
        this.code = code;
        this.data = data;
        this.message = message;
    }
 
    public int getCode() {
        return code;
    }
 
    public void setCode(int code) {
        this.code = code;
    }
 
    public Object getData() {
        return data;
    }
 
    public void setData(Object data) {
        this.data = data;
    }
 
    public String getMessage() {
        return message;
    }
 
    public void setMessage(String message) {
        this.message = message;
    }
}

2，后端向前端传输

@Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String account=req.getParameter("account");
        String password=req.getParameter("password");
        System.out.println(account);
        System.out.println(password);
        PrintWriter printWriter=resp.getWriter();
        User user= null;
        CommonData commonData=null;
        try {
            user = dao.logindao(account,password);
            if(user==null) {
                commonData=new CommonData(201,"账号或密码输入有误，请重新输入！");
            }
            else {
                commonData=new CommonData(200,user,"登录成功");
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
            commonData=new CommonData(500,"服务器忙...请稍后重试！");
        }
        ObjectMapper objectMapper=new ObjectMapper();
        String json=objectMapper.writeValueAsString(commonData);
        printWriter.print(json);
 
 
 
 
    }

3，前端接收后端传来的Json数据

login() {
				this.$http.post("LoginServlet", jsonToString(this.from)).then(resp => {
					if (resp.data.code == 201) {
						this.$message({
							message: resp.data.message,
							type: 'warning'
						});
					} else if (resp.data.code == 200) {
						this.$message({
							message: resp.data.message,
							type: 'success'
						});
						sessionStorage.setItem("account", resp.data.data.account);
						this.$router.push("/main"); //在js中进行路由导航
					}
 
				})
 
			}