从控制器中删除@ResponseBody 时，收到 404 not found 错误消息 [英] When @ResponseBody is removed from the controller, getting 404 not found error message

问题描述

我有一个 spring boot 应用程序，我在其中创建了一个带有 @Controller 注释的控制器，当我尝试使用它显示的 url 访问资源时，它显示 404，未找到".但是一旦我在类级别或方法级别添加注释 @ResponseBody ，它就会给我所需的输出.我想在这里了解 @Responsebody 的作用，为什么它会影响 url 识别.据我所知 @ResponseBody 处理响应.

I have a spring boot application in which I am creating a controller with @Controller annotation, when I tried to access the resource using the url it is showing me 404, "not found". But as soon as I add annotation @ResponseBody at class level or method level, it gives me desired output. I want to understand the role of @Responsebody here why it is affecting the url identification. As far as I know @ResponseBody deals with the responses.

当我有如下代码时 -

When I have code like below -

@Controller
@RequestMapping(value = "test")

public class TestController {

    @RequestMapping(value = "/m1")
    public @ResponseBody String testMethod(){
        return "Hello First Application";
    }
}

它给了我一个精确的输出 Hello First Application

It is giving me an exact output as Hello First Application

当我从方法 testMethod() 中删除 @ResponseBody 时，它给了我以下输出.

when I remove @ResponseBody from the method testMethod() it gives me the following output.

{
    "timestamp": "2019-06-13T06:36:14.510+0000",
    "status": 404,
    "error": "Not Found",
    "message": "No message available",
    "path": "/test/m1"
}

我期待一个字符串作为响应.

I am expecting a string as a response.

推荐答案

此链接可能会解释您的需求:https://www.baeldung.com/spring-request-response-body

This link might explain what you need: https://www.baeldung.com/spring-request-response-body

基本上，注释告诉控制器对象格式正确.@Controller 通常用于返回视图，@RestController 用于JSON，不再需要@ResponseBody.

Basically, the annotation tells the controller that the object is well formatted. @Controller is usually used for returning views, and @RestController is used for JSON, and no longer needs @ResponseBody.

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