Servlet基礎例程-HelloServlet(NT版本)

2019-11-18 15:08:29

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　　/*
作者：何志強[hhzQQ@21cn.com]
功能：Servlet基礎例程 - HelloServlet
*/

import java.io.*;
import java.text.*; //MessageFormat
import javax.servlet.*;
import javax.servlet.http.*;

public class HelloServlet extends HttpServlet{
//頁面標題
PRotected static final String strTitle = "Servlet基礎例程 - HelloServlet";

//頁眉
protected static final String strHeader =
"<Html>"+
"<head>"+
"<meta http-equiv="Content-Type" content="text/html; charset=gb2312">"+
"<title>{0}</title>"+
"</head>"+
"<body>";

//頁腳
protected static final String strFooter =
"</body>"+
"</html>";

//表單
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}，歡迎來到Servlet/jsp世界！";

//出錯信息
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前得先設置Content Type
resp.setContentType("text/html;charset=gb2312");

PrintWriter out = resp.getWriter();

//輸出頁眉
out.print(MessageFormat.format(strHeader,new Object[]{strTitle+" - 請輸入尊姓大名"}));

//輸出表單
out.print(MessageFormat.format(strForm,new Object[]{req.getContextPath()+req.getServletPath()}));

//輸出頁腳
out.print(strFooter);

out.flush();
}

protected void printHello(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException{
//獲取用戶輸入的數據
String name = req.getParameter("name");

if(name==null)
name = "無名氏";
else
//對用戶輸入的數據作必要的字符編碼轉換
name = new String(name.getBytes("iso-8859-1"));

//在使用PrintWriter前得先設置Content Type
resp.setContentType("text/html;charset=gb2312");

PrintWriter out = resp.getWriter();

//輸出頁眉
out.print(MessageFormat.format(strHeader,new Object[]{strTitle+" - 歡迎您"}));

//輸出歡迎信息
out.print(MessageFormat.format(strHello,new Object[]{name}));

//輸出頁腳
out.print(strFooter);

out.flush();
}

protected void printError(String error, HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException{
//在使用PrintWriter前得先設置Content Type
resp.setContentType("text/html;charset=gb2312");

PrintWriter out = resp.getWriter();

//輸出頁眉
out.print(MessageFormat.format(strHeader,new Object[]{strTitle+" - 出錯信息"}));

//輸出出錯信息
out.print(MessageFormat.format(strError,new Object[]{error}));

//輸出頁腳
out.print(strFooter);

out.flush();
}
}

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