004-C3P0连接池工具类模板
package ${enclosing_package}; 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 ${primary_type_name} { // 1 获得Connection ----- 从连接池中获取 private static DataSource dataSource = new ComboPooledDataSource(); // 2 创建ThreadLocal 存储的类型是Connection private static ThreadLocal<Connection> tl = new ThreadLocal<Connection>(); // 3 直接可以获取一个连接池 public static DataSource getDataSource() { return dataSource; } // 4 直接获取一个连接 public static Connection getConnection() throws SQLException{ return dataSource.getConnection(); } // 5 获取绑定到ThreadLocal上的连接对象 public static Connection getCurrentConnection() throws SQLException { //从ThreadLocal寻找 当前线程是否有对应Connection Connection con = tl.get(); if (con == null) { //获得新的connection con = dataSource.getConnection(); //将conn资源绑定到ThreadLocal(map)上 tl.set(con); } return con; } // 6 开启事务 public static void startTransaction() throws SQLException { Connection con = getCurrentConnection(); if (con != null) { con.setAutoCommit(false); } } // 7 事务回滚 public static void rollback() throws SQLException { Connection con = getCurrentConnection(); if (con != null) { con.rollback(); } } // 8 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 } } // 9 关闭资源方法 public static void close(ResultSet rs,Statement st,Connection con) throws SQLException { if (rs != null) { rs.close(); } if (st != null) { st.close(); } if (con != null) { con.close(); } } }