泛型--->Result返回結果封裝

controller的返回結果一般有兩種：

    1.Rest API JSON 輸出

    2.頁面

目的：編寫優雅的代碼

實現：通過泛型對返回結果進行封裝

 

代碼如下：

一.控制層

/**
     * 獲取用戶成功
     * @return
     */
    @RequestMapping("/getUser")
    @ResponseBody
    public Result<User> getUser(@RequestParam("id") int id){
        User user = userService.getUserById(id);
        System.out.println(user.toString());

        return Result.success(user);
    }

返回結果：{"code":0,"message":"SUCCESS","data":{"id":1,"name":"斗戰勝佛"}}

/**
     * 獲取用戶失敗
     * @param id
     * @return
     */
    @RequestMapping("/getUserFailed")
    @ResponseBody
    public Result<CodeMsg> getUserFailed(@RequestParam("id") int id){
        User user = userService.getUserById(id);
        System.out.println(user.toString());

        return Result.error(CodeMsg.SERVER_ERROR);
    }

 

返回結果：{"code":500100,"message":"服務端異常","data":null}

二：Result類

public class Result<T> {

    private int code;
    private String message;
    private T data;

    /**
     * 成功時調用
     * @param data
     * @param <T>
     * @return
     */
    public static <T> Result<T> success(T data){
        return new Result<T>(data);
    }

    /**
     * 失敗時調用
     * @param codeMsg
     * @param <T>
     * @return
     */
    public static <T> Result error(CodeMsg codeMsg){
        return new Result<T>(codeMsg);
    }

    /**
     * 構造方法私有化，不允許外部new Result
     * @param data
     */
    private Result(T data){
        this.code = 0;
        this.message = "SUCCESS";
        this.data = data;
    }

    /**
     * 構造方法私有化，不允許外部new Result
     * @param codeMsg
     */
    private Result(CodeMsg codeMsg){
        if (null == codeMsg) {
            return;
        }
        this.code = codeMsg.getCode();
        this.message = codeMsg.getMessage();
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public T getData() {
        return data;
    }

    public void setData(T data) {
        this.data = data;
    }
}

三：CodeMsg類

public class CodeMsg {

     private int code;
     private String message;

    /**
     * //通用模塊異常 5001XX
     */
    public static CodeMsg SUCCESS = new CodeMsg(0,"SUCCESS");
     public static CodeMsg SERVER_ERROR = new CodeMsg(500100,"服務端異常");

     //登陸模塊異常 5002XX
    //商品模塊異常 5003XX
    //訂單模塊異常 5004XX
    //秒殺模塊異常 5005XX


    private CodeMsg(int code, String message) {
        this.code = code;
        this.message = message;
    }

    public int getCode() {
        return code;
    }

    public String getMessage() {
        return message;
    }
}