The http interface call succeeds but returns 404

Record the problem of calling the http interface successfully but returning 404

The problem manifests itself as follows:

1. The front end calls the http interface, and the interface returns 404

2. Through debug confirmation, the interface call is successful

3. The interface will return JSON data

 
Here a case is used to demonstrate the problem

1. Backend interface code

@Controller
@RequestMapping("test")
public class TestController {
    
    

    @RequestMapping("testReturnStr")
    public String testReturnStr(HttpServletRequest request, HttpServletResponse response) {
    
    
        
        return "盖伦与卡特琳娜";
    }

}

 
2. The code returned by the front-end call is:404 , but in fact the call is normal, so I won’t take a screenshot here
 
Reason: The back-end interface returns JSON data, but the controller does not add relevant declarations

 
solve

Method 1: Change the controller @Controllerto@RestController

//使用@RestController
@RestController
@RequestMapping("test")
public class TestController {
    
    

    @RequestMapping("testReturnStr")
    public String testReturnStr(HttpServletRequest request, HttpServletResponse response) {
    
    
        
        return "盖伦与卡特琳娜";
    }

}

@ResponseBodyMethod 2: Add annotations on the controller method

@Controller
@RequestMapping("test")
public class TestController {
    
    

	//添加@ResponseBody
	@ResponseBody
    @RequestMapping("testReturnStr")
    public String testReturnStr(HttpServletRequest request, HttpServletResponse response) {
    
    
        
        return "盖伦与卡特琳娜";
    }

}