java统一返回结果集封装，解决No converter found for return value of type

网上很多，自己参照手写了一个。

package com.***.pro.utils;

/**
 * @Author: wsh
 */

public class Result<T> {
    private  Boolean success;
    private  Integer code;
    private  String message;
    private  T  data;

    private  Result(T data) {
        this.success=true;
        this.code=0;
        this.message ="成功";
        this.data = data;
    }
    private Result(CodeMsg cm) {
        if(cm == null){
            return;
        }
        this.success = false;
        this.code = cm.getCode();
        this.message = cm.getMessage();
    }
    /**
     * 成功
     */
    public static <T> Result<T> success(T data){
        return new Result<>(data);
    }

    /**
     * 成功不需要参数
     */
    public static <T> Result<T> success(){
        return (Result<T>) success("");
    }

    /**
     * 失败时候的调用，自定义错误码
     */
    public static <T> Result<T> error(CodeMsg cm){
        return new Result<T>(cm);
    }
    /**
     * 失败时候的调用,默认错误码+消息
     */
    public static <T> Result<T> error(String msg){
        CodeMsg cm= new CodeMsg(msg);
        return new Result<T>(cm);
    }







    public Boolean getSuccess() {
        return success;
    }

    public void setSuccess(Boolean success) {
        this.success = success;
    }

    public Integer getCode() {
        return code;
    }

    public void setCode(Integer 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;
    }
}

package com.***.pro.utils;

/**
 * @Author: wsh
 */
public class CodeMsg {
    private Integer code;
    private String message;


    public CodeMsg(Integer code, String message) {
        this.code = code;
        this.message = message;
    }

    public CodeMsg( String message) {
        this.code = -1;
        this.message = message;
    }

    public Integer getCode() {
        return code;
    }

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

    public String getMessage() {
        return message;
    }

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

Controller调用 

    @GetMapping("master")
    public Result master( ) {
        List<Role> roles = roleDao.queryAll(null);
        //成功
        return Result.success(roles);
    }


     @GetMapping("slave")
    public Result slave( ) {
        List<Role> roles = roleDao.queryAll(null);
        //失败
        return Result.error("不想说话");
    }

返回结果

{
    "success": true,
    "code": 0,
    "messagg": "成功",
    "data": [
        {
            "id": "1"
        }
    ]
}

 

{
    "success": false,
    "code": -1,
    "messagg": "不想说话",
    "data": null
}

 

如果出现下面的报错，就是你的返回类（我这里是Result类）没写set、get方法导致

No converter found for return value of type: class com.***.pro.utils.Result
org.springframework.http.converter.HttpMessageNotWritableException: No converter found for return value of type: class com.***.pro.utils.Result

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无意接了一个需求

package com.***.pro.utils;

/**
 * @Author: wsh
 */
public class ResultData<T> {
    private CodeMsg result;
    private   T  data;


    private  ResultData(CodeMsg codeMsg) {
        this.data=null;
        this.result =codeMsg;

    }
    private ResultData(T data) {
        CodeMsg codeMsg = new CodeMsg(0,"成功");
        this.data=data;
        this.result =codeMsg;
    }

    /**
     * 成功
     */
    public static <T> ResultData<T> success(T data){
        return new ResultData<>(data);
    }



    /**
     * 失败时候的调用，自定义错误码
     */
    public static <T> ResultData<T> error(CodeMsg cm){
        return new ResultData<T>(cm);
    }
    /**
     * 失败时候的调用,默认错误码+消息
     */
    public static <T> ResultData<T> error(String msg){
        CodeMsg cm= new CodeMsg(msg);
        return new ResultData<T>(cm);
    }

    public CodeMsg getResult() {
        return result;
    }

    public void setResult(CodeMsg result) {
        this.result = result;
    }

    public T getData() {
        return data;
    }

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

@RequestMapping("/master")
@RestController
public class TestController {

    @Autowired
    RoleDao roleDao;

    @GetMapping("master")
    public ResultData master( ) {
        List<Role> roles = roleDao.queryAll(null);
        return ResultData.success(roles);
    }

    @GetMapping("slave")
    public ResultData slave( ) {
        List<Role> roles = roleDao.queryAll(null);
        return ResultData.error("不想说话");
    }
}

浏览器访问http://127.0.0.1:8080/master/master

{
    "result": {
        "code": 0,
        "message": "成功"
    },
    "data": [
        {
            "id": "1"
        },
        {
            "id": "2"
        }
    ]
}

访问http://127.0.0.1:8080/master/slave

{
    "result": {
        "code": -1,
        "message": "不想说话"
    },
    "data": null
}