一个Javaweb综合实例

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     login.html 代码：                                           This is my loginpage.

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 users=new HashMap();

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 data=new HashMap();

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(" ");
out.println("hello "+username+",your records:

");

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

}
out.println("");

}
else
{

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

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

 
}

工程图文件及web.xml配置图

 

演示