499篇java文章

				作者：何志强
				email: hhzqq@21cn.com
				日期：2000-8-10 17:07:04
				/*
				作者：何志强[hhzqq@21cn.com]
				日期：2000-08-10
				版本：1.0
				功能：Servlet基础例程 - HelloServlet
				*/
				
				import java.io.*;
				import java.text.*; //MessageFormat
				import javax.servlet.*;
				import javax.servlet.http.*;
				
				public class HelloServlet extends HttpServlet{
				   //页面标题
				   protected static final String strTitle = "Servlet基础例程 - HelloServlet";
				
				   //页眉
				   protected static final String strHeader =
				      ""+
				      ""+
				      ""+
				      "{0}"+
				      ""+
				      "";
				
				   //页脚
				   protected static final String strFooter =
				      ""+
				      "";
				
				   //表单
				   protected static final String strForm =
				      ""+
				      "您尊姓大名："+
				      ""+
				      "";
				
				   protected static final String strHello =
				      "您好，{0}，欢迎来到Servlet/JSP世界！";
				
				   //出错信息
				   protected static final String strError =
				      "{0}";
				
				   protected void doGet(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException{
				      process(req,resp);
				   }
				
				   protected void doPost(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException{
				      process(req,resp);
				   }
				
				   protected void process(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException{
				      try{
				         String submit = req.getParameter("submit");
				         if(submit==null)
				           printForm(req,resp);
				         else
				           printHello(req,resp);
				      }
				      catch(Exception e){
				         printError(e.toString(),req,resp);
				      }
				   }
				
				   protected void printForm(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException{
				      //在使用PrintWriter前得先设置Content Type
				      resp.setContentType("text/html");
				
				      PrintWriter out = resp.getWriter();
				
				      //输出页眉
				      out.print(MessageFormat.format(strHeader,new Object[]{strTitle+" - 请输入尊姓大名"}));
				
				      //输出表单
				      out.print(MessageFormat.format(strForm,new Object[]{req.getContextPath()+req.getServletPath()}));
				
				      //输出页脚
				      out.print(strFooter);
				
				      out.flush();
				   }
				
				   protected void printHello(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException{
				      //获取用户输入的数据
				      String name = req.getParameter("name");
				
				      if(name==null)
				         name = "无名氏";
				
				      //在使用PrintWriter前得先设置Content Type
				      resp.setContentType("text/html");
				
				      PrintWriter out = resp.getWriter();
				
				      //输出页眉
				      out.print(MessageFormat.format(strHeader,new Object[]{strTitle+" - 欢迎您"}));
				
				      //输出欢迎信息
				      out.print(MessageFormat.format(strHello,new Object[]{name}));
				
				      //输出页脚
				      out.print(strFooter);
				
				      out.flush();
				   }
				
				   protected void printError(String error, HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException{
				      //在使用PrintWriter前得先设置Content Type
				      resp.setContentType("text/html");
				
				      PrintWriter out = resp.getWriter();
				
				      //输出页眉
				      out.print(MessageFormat.format(strHeader,new Object[]{strTitle+" - 出错信息"}));
				
				      //输出出错信息
				      out.print(MessageFormat.format(strError,new Object[]{error}));
				
				      //输出页脚
				      out.print(strFooter);
				
				      out.flush();
				   }
				}