preface:

First, post the error report log

Resolved [org.springframework.http.converter.HttpMessageNotWritableException: No converter found for return value of type: class com.test.dto.ResultBean]

If the log is similar, you can continue to look down.

1. Causes and Solutions

Restore the accident scene first (only show the core problem code)

Interface layer code:

@RestController
@RequestMapping("/client")
public class ControllerTest {

    @GetMapping("/test")
    public ResultBean name() {
        return ResultBean.success();
    }
}

ResultBean Code:

public class ResultBean {

    private String code;
    private String result;

    ResultBean(String code, String result) {
        this.code = code;
        this.result = result;
    }

    public static ResultBean success() {
        return new ResultBean("200", "success");
    }

}

The error log points to this   ResultBean. The big probability is that there is a problem with this bean. After careful analysis of the log, it probably means that it is impossible to get the value, so it is impossible to write. Get the value?Get method?It seems that ResultBean is missing the get method (Lombok annotation is forgotten). With the get method, the problem is solved

Tips: be sure to add get and set methods and try to write by hand; Lombok annotations are rarely used. There are holes in them. Occasionally, the default method for generating special fields cannot be recognized by other components.