关于Request请求的各种路径问题

转载自：https://blog.csdn.net/qq_27770257/article/details/79438987

最近对于request中的几种“路径”有点混淆，查找网上资源都没有很好的总结，希望此文章能够帮助我理解一下这几种“路径”。 

+++++++++++++++++++++++++++++++++++++++++++++++++  本文章主要讨论以下几种request获取路径的方法： request.getServletPath() request.getPathInfo() request.getContextPath() request.getRequestURI() request.getRequestURL() request.getServletContext().getRealPath()

以一个简单的例子说明： web.xml配置（注意此处的url-pattern项）

<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>aab</display-name> <welcome-file-list> <welcome-file>a.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>test</servlet-name> <servlet-class>com.java.test.TestServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>test</servlet-name> <url-pattern>/*</url-pattern><!-- 注意此处 --> </servle

TestServlet.java文件：

package com.java.test; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class TestServlet extends HttpServlet{ @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println("servletPath:"+req.getServletPath()); System.out.println("contextPath:"+req.getContextPath()); System.out.println("contextPath2:"+req.getServletContext().getContextPath()); System.out.println("pageInfo:"+req.getPathInfo()); System.out.println("uri:"+req.getRequestURI()); System.out.println("url:"+req.getRequestURL()); System.out.println("realPath:"+req.getServletContext().getRealPath("/")); } }

此时请求http://localhost:8080/testweb (url-pattern=/*) 打印出来的值为：

servletPath: contextPath:/testweb contextPath2:/testweb pageInfo:null uri:/testweb url:http://localhost:8080/testweb realPath:G:\java\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\testweb\

请求http://localhost:8080/testweb/abc 打印的值为：

servletPath: contextPath:/testweb contextPath2:/testweb pageInfo:/abc uri:/testweb/abc url:http://localhost:8080/testweb/abc realPath:G:\java\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\testweb\

当我们修改web.xml为如下时（注意url-pattern的改变）：

<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>aab</display-name> <welcome-file-list> <welcome-file>a.jsp</welcome-file> </welcome-file-list> <servlet> <servlet-name>test</servlet-name> <servlet-class>com.java.test.TestServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>test</servlet-name> <url-pattern>/abc/def/*</url-pattern><!-- 注意此处 --> </servlet-mapping> </web-app>

请求http://localhost:8080/testweb/abc/def/ghi/test.html (url-pattern=/abc/def/*) 打印的值为：

servletPath:/abc/def contextPath:/testweb contextPath2:/testweb pageInfo:/ghi/test.html uri:/testweb/abc/def/ghi/test.html url:http://localhost:8080/testweb/abc/def/ghi/test.html realPath:G:\java\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\testweb\

通过观察打印结果，我们可以总结： 1. getServletPath():获取能够与“url-pattern”中匹配的路径，注意是完全匹配的部分，*的部分不包括。 2. getPageInfo():与getServletPath()获取的路径互补，能够得到的是“url-pattern”中*d的路径部分 3. getContextPath():获取项目的根路径 4. getRequestURI:获取根路径到地址结尾 5. getRequestURL:获取请求的地址链接（浏览器中输入的地址） 6. getServletContext().getRealPath(“/”):获取“/”在机器中的实际地址 7. getScheme():获取的是使用的协议(http 或https) 8. getProtocol():获取的是协议的名称(HTTP/1.11) 9. getServerName():获取的是域名(xxx.com) 10. getLocalName:获取到的是IP