javaee数据库连接池C3P0

package com.it.util;

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

import javax.sql.DataSource;

import com.mchange.v2.c3p0.ComboPooledDataSource;
//注意包一定要导对
public class C3P0Util {
//得到一个数据源
private static DataSource dataSource = new ComboPooledDataSource();

//从数据源中得到一个连接对象
public static Connection getConnection(){
try {
return dataSource.getConnection();
} catch (SQLException e) {
throw new RuntimeException("服务器错误");
}
}

public static void release(Connection conn,Statement stmt,ResultSet rs){
//关闭资源
if(rs!=null){
try {
rs.close();
} catch (Exception e) {
e.printStackTrace();
}
rs = null;
}
if(stmt!=null){
try {
stmt.close();
} catch (Exception e) {
e.printStackTrace();
}
stmt = null;
}
if(conn!=null){
try {
conn.close();//关闭
} catch (Exception e) {
e.printStackTrace();
}
cOnn= null;
}
}

}

package com.it.dao;

import java.util.List;

import com.ithema.domain.User;

public interface UserDao {
public List findUsers(String sql);
}

package com.it.dao.impl;

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


import com.it.dao.UserDao;
import com.it.domain.User;
import com.it.util.C3P0Util;

public class UserDaoImpl implements UserDao {

public List findUsers(String sql) {
Connection cOnn=null;
PreparedStatement ps=null;
ResultSet rs=null;
List list=new ArrayList();

cOnn=C3P0Util.getConnection();
try {
ps= conn.prepareStatement(sql);
rs=ps.executeQuery();
while(rs.next()) {
User user=new User();
user.setName(rs.getString(2));
user.setPassword(rs.getString(3));
user.setEmail(rs.getString(4));
user.setBirthday(rs.getDate(5) );
list.add(user);
}
return list;
} catch (SQLException e) {
throw new RuntimeException("服务器错误");
}


}

}

<%@page import="java.util.ArrayList"%>
<%@page import="java.util.List"%>
<%@page import="com.it.domain.User"%>
<%@page import="com.it.dao.impl.UserDaoImpl"%>
<%@ page language="java" cOntentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>








<%
UserDaoImpl dao=new UserDaoImpl();
List list;
list=dao.findUsers("select * from users");
request.setAttribute("list", list);
 %>
 
 








 








 
 








 
 
用户名
 
密码
 
邮箱
 
生日
 
  
 
${list[i].name }
 
${list[i].password }
 
${list[i].email }
 
${list[i].birthday }
 
   
 
${l.name }
 
${l.password }
 
${l.email }
 
${l.birthday }