c3p0连接池封装

在处理数据库事物时需要同一个Connection  但是dbcp无法获得  单独工具也显得繁琐，改进成c3p0工具类：

package utils;

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 DataSourceUtils {

private static DataSource dataSource = new ComboPooledDataSource();

private static ThreadLocal<Connection> tl = new ThreadLocal<Connection>();

// 直接可以获取一个连接池
public static DataSource getDataSource() {
return dataSource;
}

public static Connection getConnection() throws SQLException{
return dataSource.getConnection();
}

// 获取连接对象
public static Connection getCurrentConnection() throws SQLException {

Connection con = tl.get();
if (con == null) {
con = dataSource.getConnection();
tl.set(con);
}
return con;
}

// 开启事务
public static void startTransaction() throws SQLException {
Connection con = getCurrentConnection();
if (con != null) {
con.setAutoCommit(false);
}
}

// 事务回滚
public static void rollback() throws SQLException {
Connection con = getCurrentConnection();
if (con != null) {
con.rollback();
}
}

// 提交并且 关闭资源及从ThreadLocall中释放
public static void commitAndRelease() throws SQLException {
Connection con = getCurrentConnection();
if (con != null) {
con.commit(); // 事务提交
con.close();// 关闭资源
tl.remove();// 从线程绑定中移除
}
}

// 关闭资源方法
public static void closeConnection() throws SQLException {
Connection con = getCurrentConnection();
if (con != null) {
con.close();
}
}

public static void closeStatement(Statement st) throws SQLException {
if (st != null) {
st.close();
}
}

public static void closeResultSet(ResultSet rs) throws SQLException {
if (rs != null) {
rs.close();
}
}

}

映入连接：

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
    <default-config>
        <property name="user">root</property>
        <property name="password">root</property>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql:///xiaomi</property>
    </default-config>
</c3p0-config>