What is the difference between adding a slash (/) in front of a Spring MVC path and not adding a slash?

Foreword: Yesterday I finished building the framework of the spring mvc project, but I found that I can't access the page anymore. After carefully looking at the code, I found that: When the path jumps, I added an extra / slash in front of the path, which caused the requested path to occur Error, let’s share with you about the path forward slash problem

1. About the request path:

Only a correct request path can access the resources of the server, the request path is composed of the resource path and the resource name

例如： http://localhost:8080/springmvc/test/hello

Where http://localhost:8080/springmvc/test is the resource path and hello is the resource name

2. Request path classification:

The request path is divided into front-end path and back-end path . The path in the jsp page is the front-end path. If the path in .xml can be said to be the back-end path, this time I mainly introduce the front-end path, and the front-end path will be divided into Two types: relative path and absolute path.

3. The request path is divided into relative path and absolute path:

For example: http://localhost:8080/springmvc/test/hello is an absolute path (full path), which can accurately locate a resource

For example: /test/hello or test/hello are relative paths, they will rely on one other path as the most reference path

If you look carefully, you will find: Why is there a slash (/) in front of the same relative path? This is the main content shared in this blog.

If the path is resolved in the foreground, the root path is http://localhost:8080/
If the path is resolved in the background, the root path is http://localhost:8080/project name/

Look at an example:

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <h3>入门程序</h3>

    <!--
        当前路径是前面没有斜杠的相对路径，参照的路径就是当前页面的路径：
参照的路径是http://localhost:8008/项目名/requestMapping
http://localhost:8008/test/requestMapping
    -->
    <a href="requestMapping">前面没有斜杠</a>

    <!--当前路径是一个有斜杠的相对路径，参照路径就是当前的web服务器的根路径：http://localhost:8008/
    点击链接之后提交的URL绝对地址是：  http：//localhost:8008/requestMapping
   -->
    <a href="/requestMapping">前面有斜杠</a>
</body>
</html>

Controller:

  */
@Controller

public class HelloController {
    @RequestMapping(path="/requestMapping")
    public String testRequestmapping(){
        System.out.println("hello spring mvc");
        return "success";
    }
}

Initial page:

When we click on the first hyperlink, there is no slash in front of the relative path:

The URL in the address bar becomes:

The green part in the front is the reference path of the relative path (ie http://localhost:8008/test/haha/), which is the path before we clicked on the link.

When we click on a link with a slash in front:

The URL becomes:

We can find that the reference path of the relative path has become the root directory (ie http://localhost:8008/)

What is the difference between adding a slash (/) in front of a Spring MVC path and not adding a slash?

Look at an example:

Summary: The reference path without a slash in front of the relative path of the front-end path is the path currently visited

The reference path with a slash in front of the relative path of the front path is the root path

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