关于springMVC和传统servlet框架从jsp页面向后台请求url问题

港控/mmm° 2022-06-16 02:42 126阅读 0赞

经过实验  发现

servlet和springmvc向后台发送请求都是根据request.getServletPath()来获取请求的

如果jsp中没有<base href="<%=basePath%>">则向后台的请求会自动解析到项目根目录下 加上以后会自动解析到文件的当前目录下  
举个例子

![Center][]

如上图项目(两个jsp内容一样)

jsp内容

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    <form action="login.action" method="post">
    用户名<input type="text" name="userName">
    密码<input type="text" name="password">
    <input type="submit" value="submit">
    </form>
    </body>
    </html>

Test是个servlet代码如下

package com;
    
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    /**
     * Servlet implementation class Test
     */
    public class Test extends HttpServlet {
    	private static final long serialVersionUID = 1L;
           
        /**
         * @see HttpServlet#HttpServlet()
         */
        public Test() {
            super();
            // TODO Auto-generated constructor stub
        }
    
    	/**
    	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
    	 */
    	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		this.doPost(request, response);
    	}
    
    	/**
    	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
    	 */
    	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		System.out.println("request.getServletPath()="+request.getServletPath());
    		System.out.println("request.getContextPath()="+request.getContextPath());
    		
    	}
    
    }

1.此时浏览器输入http://localhost:8080/TestServlet/page/NewFile.jsp      
控制台输出

request.getServletPath()=/page/login.action  
request.getContextPath()=/TestServlet  
  
2.浏览器输入http://localhost:8080/TestServlet/page/a/NewFile.jsp      
控制台输出  
request.getServletPath()=/page/a/login.action  
request.getContextPath()=/TestServlet

\-----------------------------------------------------------------------------------------------------------------------------------------------------------------

如果在两个jsp中加入basepath  
jsp代码如下

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
        <%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    
    <head>
    <base href="<%=basePath%>" />
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    <form action="login.action" method="post">
    用户名<input type="text" name="userName">
    密码<input type="text" name="password">
    <input type="submit" value="submit">
    </form>
    </body>
    </html>

1.此时浏览器输入http://localhost:8080/TestServlet/page/NewFile.jsp

控制台输出  
request.getServletPath()=/login.action  
request.getContextPath()=/TestServlet  
  
  
2.浏览器输入http://localhost:8080/TestServlet/page/a/NewFile.jsp      
控制台输出  
request.getServletPath()=/login.action  
request.getContextPath()=/TestServlet

**通过以上实验可以看出request.getServletPath()在jsp中加入basepath的时候会直接获取到请求   如果不加会从项目根目录开始获取请求路径  
  
在springMVC中是一样的道理 springMVC实际也是通过request.getServletPath()获取请求的**  
  
  
  
  
springMVC和servlet都是根据这种获取的请求并解析  所以当用springmvc发送请求报404的时候后台报no mapping时可能会是这个原因(请求路径不对应)

ps：这个basePath代码  
<%  
String path = request.getContextPath();  
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";  
%>  
<base href="<%=basePath%>" />

[Center]: /images/20220616/d4c51500eb85404bb42be09187c0e449.png