一个Javaweb综合实例

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最新推荐文章于 2023-06-12 09:45:34 发布

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本文介绍了一个使用JavaWeb技术的银行事务处理示例，包括登录验证和账户信息展示。通过两个Servlet（LoginServlet和AccountServlet）实现了用户登录和账户记录的显示。

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一个Javaweb综合实例

http://mapdf.net/show.asp?id=3824

一个Javaweb综合实例
在实际应用中仅用一个servlet来完成所有的任务是不实际的通常
我们把业务处理分成多个任务，每个任务用一个serverlet来处理
下面是一个简化的银行事务的例子，然后包含下列组件。
login.html error.html
LoginServlet
AccountServlet

用户通过login.html页面验证登录信息再显示Account信息。实现servlet之间的数据传送

<!DOCTYPE html>

<html>

<head>

<title>login.html</title>

</head>

<body>

This is my loginpage. <br>

</html>

longinservlet 和 accouservlet 代码

longinservlet

package com.demo;
import java.io.*;
import java.util.HashMap;

import javax.servlet.*;
import javax.servlet.http.*;
public class Loginservlet extends HttpServlet
{
ServletContext context;
HashMap<String,String > users=new HashMap<String, String >();

public void init(){
context=getServletContext();
users.put("ann","aaa");
users.put("john","jjj");
users.put("mark","mmm");

}

public void doGet(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException{
doPost(request,response);}

public void doPost(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException{
String username=request.getParameter("username");
String password=request.getParameter("password");
if(username!=null&&password!=null&&password.equals(users.get(username))){

request.setAttribute("username", username);
RequestDispatcher view=context.getRequestDispatcher("/account.do");
view.forward(request, response);
return;

}
else
{
RequestDispatcher view=context.getRequestDispatcher("/Error.html");
view.forward(request, response);
return;
}
}
}

accouservle

package com.demo;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

import java.util.HashMap;
public class acountservlet extends HttpServlet {
ServletContext context;
HashMap<String,String[]> data=new HashMap<String, String[]>();

public void init()
{
context=getServletContext();
data.put("ann", new String[]{
"20090101:1300.00",
"20090201:1200.00",
"20090401:1400.00"

});
data.put("John", new String[]{
"20090101:1300.00",
"20090201:1200.00",
"20090401:1400.00"

});
data.put("mark", new String[]{
"20090101:1300.00",
"20090201:1200.00",
"20090401:1400.00"

});
}

public void doPost(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException{
String username=(String)request.getAttribute("username");
if(username!=null){

String[] records=(String[]) data.get(username);

response.setContentType("html;charset=gb2312");

PrintWriter out=response.getWriter();

out.println("<html> <body> ");
out.println("hello "+username+",your records:<p>");

for(int i=0;i<records.length;i++)
{
out.println(records[i]+"<br>");

}
out.println("</html></body>");

}
else
{

RequestDispatcher view=context.getRequestDispatcher("/login.html");
view.forward(request, response);

}
}
public void doGet(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException{
doPost(request,response);
}

}