c3p0封装

配置文件

 <?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:///day35</property>
     </default-config>
 </c3p0-config> 

Java

 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();
         }
     }

 }