用JSP+JavaBean开发模式实现一个销售额的查询

数据库使用mysql，如下：

vo包的Sales类：

package com.vo;

public class Sales {
public String salestime;
public float salesnum;
public String getSalestime() {
  return salestime;
}
public void setSalestime(String salestime) {
  this.salestime = salestime;
}
public float getSalesnum() {
  return salesnum;
}
public void setSalesnum(float salesnum) {
  this.salesnum = salesnum;
}

}

dao包中的DBManager类：

package com.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DbManager {

        private static String URL = "jdbc:mysql://localhost:3306/sales";
        private static String USER = "root";
        private static String PWD = "root";
        public static Connection getConn(){
            Connection conn = null;
            try {
                Class.forName("com.mysql.jdbc.Driver");
                conn = DriverManager.getConnection(URL,USER,PWD);
            } catch (SQLException e) {
                e.printStackTrace();
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }
            return conn;
        }

        public static void closeAll(Connection conn,Statement ste,ResultSet rs){
            if(rs != null){
                try {
                    rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(ste !=null){
                try {
                    ste.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(conn !=null){
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }

}

dao包中的SalesDao类：

package com.dao;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import com.vo.Sales;

public class SalesDao {
public List<Sales> find(String month) {
  Connection con = null;
  Statement state = null;
  ResultSet resultSet = null;
  List<Sales> list = null;
  String sql = "select * from sales where salestime like '" + month + "-%'" ;
  con = DbManager.getConn();
  try {
   state = con.createStatement();
   resultSet = state.executeQuery(sql);
   while(resultSet.next()){
    if(null == list){
     list = new ArrayList<Sales>();
    }
    Sales sales = new Sales();
    sales.setSalestime(resultSet.getString("salestime"));
    sales.setSalesnum(resultSet.getFloat("salesnum"));
    list.add(sales);
   }
  } catch (SQLException e) {
   e.printStackTrace();
  }finally{
   DbManager.closeAll(con, state, resultSet);
  }
  return list;
}
}

index.jsp页面：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <base href="<%=basePath%>">

    <title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

</head>

<body>
    <form action="show.jsp" method="post">
    请选择查询的月份:
    <select name="month">
      <option value="1">1月</option>
      <option value="2">2月</option>
      <option value="3">3月</option>
      <option value="4">4月</option>
      <option value="5">5月</option>
      <option value="6">6月</option>
      <option value="7">7月</option>
      <option value="8">8月</option>
      <option value="9">9月</option>
      <option value="10">10月</option>
      <option value="11">11月</option>
      <option value="12">12月</option>
    </select>
    <input type="submit" value="查询"/>
    </form>
</body>
</html>

show.jsp页面：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ page language="java" import="com.dao.*" %>
<%@ page language="java" import="com.vo.*" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <base href="<%=basePath%>">

    <title>My JSP 'show.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

</head>

<body>
    <table>
    <tr>
      <td>销售日期</td>
      <td>销售额</td>
    </tr>
    <%
      String month = request.getParameter("month");
      SalesDao dao = new SalesDao();
      List<Sales> list = dao.find(month);
      if(list != null){
       for(Sales sales : list){
    %>
    <tr>
      <td><%=sales.getSalestime() %></td>
      <td><%=sales.getSalesnum() %></td>
    </tr>
    <%
       }
      }else{
    %>
    <tr>
      <td colspan="2">暂时没有数据</td>
    </tr>
    <%
      }
    %>
    </table>
</body>
</html>

结果展示：

如图，选择1月，点击查询按钮，出现如下情况：