No converter found for return value of type: class XXX.XXX....

 网上很多的解决办法，添加依赖，写配置类啥的，都不管用，这里记录一下

出现这种问题的主要原因就是在controller中使用的是@Restcontroller,想要返回的是JSON类型的数据，但是返回的数据没办法转换成JSON，话不多说，上例子：

首先我定义一个Result的类，主要是想用Result.ok的方式，直接返回JSON数据给前台

public class Result implements Serializable {

    private String status;
    private String msg;
    private Object data;

    public static Result buildResult(String status, String msg, Object data){
        return new Result(status,msg,data);
    }
    public static Result ok(Object data){
        return new Result(data);
    }
    public Result(String status,String msg,Object data){
        this.data = data;
        this.msg = msg;
        this.status = status;
    }
    public Result(Object data){
        this.data = data;
    }
}

　　然后我的controller文件是这样的

@RestController
public class TestController {
    @Autowired
    TestMapper testMapper;

    @GetMapping(value = "/test")
    public Result test(){
        Map<String,String> map = new ConcurrentHashMap<>();
        map.put("test","test");
        map.put("test1","test2");
        map.put("test2", String.valueOf(testMapper.getTest()));
        return Result.ok(map);
    }
}

　然后在页面访问这个地址报500，查看后台控制台，有如下内容

Resolved [org.springframework.http.converter.HttpMessageNotWritableException: No converter found for return value of type: class com.electric.datacenter.entity.Result]

　不废话，直接上解决办法，就是添加getter，setter的方法就可以了，如下

public class Result implements Serializable {

    private String status;
    private String msg;
    private Object data;

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public Object getData() {
        return data;
    }

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

    public static Result buildResult(String status, String msg, Object data){
        return new Result(status,msg,data);
    }
    public static Result ok(Object data){
        return new Result(data);
    }
    public Result(String status,String msg,Object data){
        this.data=data;
        this.msg=msg;
        this.status=status;
    }
    public Result(Object data){
        this.data=data;
    }
}