HttpServletRequest

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class RequestLineServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html; charset=GB2312"); 
        PrintWriter out = response.getWriter();
         
        out.println("getMethod:" + request.getMethod() + "<br>");
        // 返回位于主机和端口之后、参数部分之前的那部分内容
        out.println("getRequestURI:" + request.getRequestURI() + "<br>");
        // 返回参数部分，无参数返回null
        out.println("getQueryString:" + request.getQueryString() + "<br>");
        // 返回协议名和版本号
        out.println("getProtocol:" + request.getProtocol() + "<br>");
        // 返回Web应用程序的路径（虚拟目录），这个路径以“/”开头
        out.println("getContextPath:" + request.getContextPath() + "<br>");
        // 返回servlet映射的路径（web.xml的url-pattern属性）
        out.println("getServletPath:" + request.getServletPath() + "<br>");
    }
}

参考文献：http://my.oschina.net/u/1171518/blog/221452