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 =
"<html>"+
"<head>"+
"<meta http-equiv=""Content-Type"" content=""text/html; charset=gb2312"">"+
"<title>{0}</title>"+
"</head>"+
"<body>";
//页脚
protected static final String strFooter =
"</body>"+
"</html>";
//表单
protected static final String strForm =
"<form action=""{0}"" method=""post"">"+
"您尊姓大名：<input type=""text"" name=""name"">"+
"<input type=""submit"" name=""submit"" value=""提交"">"+
"</form>";
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 =
"<h2><font color=""#ff0000"">{0}</font></h2>";
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();
}
}
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