C3P0模板

1.创建c3p0-config.xml配置文件放在src下

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>

	<!-- default-config 默认的配置，  -->
  <default-config>
    <property name="driverClass">com.mysql.jdbc.Driver</property>
    <property name="jdbcUrl">jdbc:mysql://localhost/mydb</property>
    <property name="user">root</property>
    <property name="password">root</property>

    <property name="initialPoolSize">10</property>
    <property name="maxIdleTime">30</property>
    <property name="maxPoolSize">100</property>
    <property name="minPoolSize">10</property>
    <property name="maxStatements">200</property>
  </default-config>

   <!-- This app is massive! -->
  <named-config name="oracle">
    <property name="acquireIncrement">50</property>
    <property name="initialPoolSize">100</property>
    <property name="minPoolSize">50</property>
    <property name="maxPoolSize">1000</property>

    <!-- intergalactoApp adopts a different approach to configuring statement caching -->
    <property name="maxStatements">0</property>
    <property name="maxStatementsPerConnection">5</property>

    <!-- he's important, but there's only one of him -->
    <user-overrides user="master-of-the-universe">
      <property name="acquireIncrement">1</property>
      <property name="initialPoolSize">1</property>
      <property name="minPoolSize">1</property>
      <property name="maxPoolSize">5</property>
      <property name="maxStatementsPerConnection">50</property>
    </user-overrides>
  </named-config>

</c3p0-config>
	

2.创建JDBCUtil

package com.rick.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;

public class JDBCUtil {

	static ComboPooledDataSource dataSource = null;
	static{
		dataSource = new ComboPooledDataSource();
	}

	/**
	 * 数据库连接池C3P0
	 * @return
	 * @throws SQLException
	 */
	public static DataSource getDataSouce() {
		return dataSource;
	}
	/**
	 * 获取连接对象
	 * @return
	 * @throws SQLException
	 */
	public static Connection getConn() throws SQLException{
		return dataSource.getConnection();
	}

	/**
	 * 释放资源
	 * @param conn
	 * @param st
	 * @param rs
	 */
	public static void release(Connection conn , Statement st , ResultSet rs){
		closeRs(rs);
		closeSt(st);
		closeConn(conn);
	}
	public static void release(Connection conn , Statement st){
		closeSt(st);
		closeConn(conn);
	}

	private static void closeRs(ResultSet rs){
		try {
			if(rs != null){
				rs.close();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally{
			rs = null;
		}
	}

	private static void closeSt(Statement st){
		try {
			if(st != null){
				st.close();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally{
			st = null;
		}
	}

	private static void closeConn(Connection conn){
		try {
			if(conn != null){
				conn.close();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally{
			conn = null;
		}
	}
}

怎么用呢？

public class StudentDaoImpl implements StudentDao{
	/*
	 * 抛异常的时候父类没有抛子类不能直接抛，所以去父类先抛一下
	 */
//查找所有
	@Override
	public List<Student> findAll() throws SQLException {
		QueryRunner runner = new QueryRunner(JDBCUtil.getDataSouce());
		String sql = "select * from stu";
		List<Student> list = runner.query(sql, new BeanListHandler<Student>(Student.class));
		return list;
	}
//添加
	@Override
	public void insert(Student student) throws SQLException {
		QueryRunner runner = new QueryRunner(JDBCUtil.getDataSouce());
		runner.update("insert into stu values(null,?,?,?,?,?,?)",
				student.getSname(),student.getGender(),student.getPhone(),
				student.getBirthday(),student.getHobby(),student.getInfo());
	}
//删除
	@Override
	public void delete(Integer sid) throws SQLException {
		QueryRunner runner = new QueryRunner(JDBCUtil.getDataSouce());
		runner.update("delete  from stu where sid = ?",sid);
	}
//查找单个
	@Override
	public Student findStudentById(Integer sid) throws SQLException {
		QueryRunner runner = new QueryRunner(JDBCUtil.getDataSouce());
		Student student = runner.query("select * from stu where sid = ?", new BeanHandler<Student>(Student.class),sid);
		return student;
	}
//修改
	@Override
	public void update(Student student) throws SQLException {
		QueryRunner runner = new QueryRunner(JDBCUtil.getDataSouce());
		runner.update("update stu set sname=?,gender=?,phone=?,birthday=?,hobby=?,info=? where sid=?",
				student.getSname(),student.getGender(),student.getPhone(),
				student.getBirthday(),student.getHobby(),student.getInfo(),
				student.getSid());
	}

}