Web應用中request獲取path，URI，URL

Web應用中有各種獲取path或URI，URL的方法，假設網頁訪問地址:

http://localhost:8080/tradeload/TestServlet

Web應用context: /tradeload 

各路徑鑒定如下：

 request.getContextPath()= /tradeload
 request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()= http://localhost:8080
 request.getRequestURL() = http://localhost:8080/tradeload/TestServlet
 request.getRequestURI() = /tradeload/TestServlet
 request.getPathInfo() = null
 request.getServletPath() = /TestServlet
 getServletContext().getRealPath('/') = C:\server\glassfish\domains\domain1\applications\j2ee-modules\tradeload\

其中的servletpath就是web.xml中配置的url-pattern。

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假定你的web application 名稱為news,你在瀏覽器中輸入請求路徑： 
http://localhost:8080/news/main/list.jsp 
則執行下面向行代碼后打印出如下結果：
 1、System.out.println(request.getContextPath());
 打印結果：/news
 2、System.out.println(request.getServletPath());
 打印結果：/main/list.jsp
 3、System.out.println(request.getRequestURI());
 打印結果：/news/main/list.jsp
 4、System.out.println(request.getRealPath("/"));
 打印結果：F:\Tomcat 6.0\webapps\news\test

String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

out.println("basePath:"+basePath);
out.println("<br/>");
out.println("getContextPath:"+request.getContextPath());
out.println("<br/>");
out.println("getServletPath:"+request.getServletPath());
out.println("<br/>");
out.println("getRequestURI:"+request.getRequestURI());
out.println("<br/>");
out.println("getRequestURL:"+request.getRequestURL());
out.println("<br/>");
out.println("getRealPath:"+request.getRealPath("/"));
out.println("<br/>");
out.println("getServletContext().getRealPath:"+getServletContext().getRealPath("/"));
out.println("<br/>");
out.println("getQueryString:"+request.getQueryString());

 

顯示結果：

basePath:http://localhost:8080/test/

getContextPath:/test
getServletPath:/test.jsp
getRequestURI:/test/test.jsp
getRequestURL:http://localhost:8080/test/test.jsp
getRealPath:D:\Tomcat 6.0\webapps\test\
getServletContext().getRealPath:D:\Tomcat 6.0\webapps\test\
getQueryString:p=fuck

在一些應用中，未登錄用戶請求了必須登錄的資源時，提示用戶登錄，此時要記住用戶訪問的當前頁面的URL，當他登錄成功后根據記住的URL跳回用戶最后訪問的頁面：

String lastAccessUrl = request.getRequestURL() + "?" + request.getQueryString();