saving.java

网上银行管理系统

package cn.edu.ccut;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.naming.Context;
import javax.sql.DataSource;
import java.sql.*;
import java.io.PrintWriter;
import java.io.IOException;

/**
 * Created by IntelliJ IDEA.
 * User: hvst
 * Date: 2008-8-25
 * Time: 13:30:19
 * To change this template use File | Settings | File Templates.
 */
public class Saving extends HttpServlet {

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

           String strUserId         = "";
           String strOperated       = "";
           String strOperatedMoney  = "";
           Double strLeftOver       = 0.0;
           Double nowLeftOver            ;
           String strSql            = "";
           String strSqll           = "";

           Context ctx              = null;
           DataSource ds            = null;
           Connection conn          = null;
           Statement stmt           = null;
           ResultSet rs             = null;
           PrintWriter out          = null;
           strUserId = (String)request.getSession().getAttribute("userId");
           try {
               response.setContentType("text/html;charset=gb2312");
               out = response.getWriter();

               Class.forName("com.mysql.jdbc.Driver");
               conn = DriverManager.getConnection("jdbc:mysql://localhost/bank?useUnicode=true&characterEncoding=gb2312", "root", "");
               stmt = conn.createStatement();
               strOperatedMoney = request.getParameter("withdrawal");

               strSql = " select leftover " +
                       " from `slimsy`" +
                       " where userid='" + strUserId + "'";
               rs = stmt.executeQuery(strSql);

               while(rs.next()){
                   strLeftOver = rs.getDouble("leftover");
               }
               if(Double.parseDouble(strOperatedMoney) >= 0.0){
                   nowLeftOver = strLeftOver + Double.parseDouble(strOperatedMoney);
                   strSqll = " update `slimsy` " +
                             " set leftover='" + nowLeftOver + "'" +
                             " where userid='" + strUserId + "'";
                    stmt.executeUpdate(strSqll);

                   String strSqlv="";
                   strSqlv = " insert into `useroperationt` (userid,operated,operatedmoney,timed)" +
                             " values ('" + strUserId + "','1','" + strOperatedMoney + "',sysdate())";

                   stmt.execute(strSqlv);

                   RequestDispatcher dispatcher = request.getRequestDispatcher("/jsp/operate.jsp");
                   dispatcher.forward(request,response);
               } else{
                   out.println("<script language='javascript'>");
                   out.println("alert('存款失败！');");
                   out.println("window.history.back();");
                   out.println("</script>");
               }

           } catch (Exception e) {
               e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
           }  finally {
               try {
                   if (rs != null) rs.close();
                   if(stmt != null) stmt.close();
                   if(conn != null) conn.close();
               } catch (SQLException e) {
                   e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
               }
           }
       }
   }