[Java]具备全程事务控制的JDBC连接管理器

　　Hibernate事务具备全局管理能力，配合Spring框架就可以在BO层完成DAO操作和事务控制。当然，传统的JDBC是不具备这个能力的，所以要自己开发一个连接管理器框架，来管理线程范围内的数据库连接和事务控制。

[java]
package edu.softparty.base.dbunit;

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

import javax.sql.DataSource;

/**
* 连接管理器类
*/
public class ConnectionManager {

    /**
     * 空的事务对象
     */
    private static final Transaction EMPTY_TRANSACTION = new Transaction() {
        public void rollback() throws SQLException {
        }
        public void commit() throws SQLException {
        }
    };

    /**
     * 负责提交和回滚的事务对象
     */
    private static final Transaction TRANSACTION = new Transaction() {
        public void rollback() throws SQLException {
            Connection connection = connectionHolder.get();
            if (connection != null) {
                if (connection.getAutoCommit() == false) {
                    connection.rollback();
                }
                connection.close();
                connectionHolder.remove();
            }
        }

        public void commit() throws SQLException {
            Connection connection = connectionHolder.get();
            if (connection != null) {
                if (connection.getAutoCommit() == false) {
                    connection.commit();
                }
                connection.close();
                connectionHolder.remove();
            }
        }
    };

    // 线程本地对象管理器
    private static final ThreadLocal<Connection> connectionHolder = new ThreadLocal<>();

    // 数据源
    private DataSource dataSource;

    /**
     * 构造器
     * @param dataSource 数据源对象
     */
    ConnectionManager(DataSource dataSource) {
        this.dataSource = dataSource;
    }

    /**
     * 获取数据库连接
     * @return 数据库连接
     * @throws SQLException
     */
    public Connection getConnection() throws SQLException {
        Connection connection = connectionHolder.get();
        if (connection == null) {
            connection = dataSource.getConnection();
            connectionHolder.set(connection);
        }
        return connection;
    }

    /**
     * 启动事务
     * @return 事务管理对象
     * @throws SQLException
     */
    public Transaction beginTransaction() throws SQLException {
        Connection connection = getConnection();
        if (connection.getAutoCommit()) {
            connection.setAutoCommit(false);
        }
        return TRANSACTION;
    }

    /**
     * 获取事务
     * @return
     * @throws SQLException
     */
    public Transaction getTransaction() {
        return connectionHolder.get() == null ? EMPTY_TRANSACTION : TRANSACTION;
    }

    /**
     * 关闭数据库连接
     * @throws SQLException
     */
    public void close() throws SQLException {
        Connection connection = connectionHolder.get();
        if (connection != null) {
            connection.close();
            connectionHolder.remove();
        }
    }

    /**
     * 释放资源
     * @param rs 结果集对象
     * @param stm 命令集对象
     * @throws SQLException
     */
    public void release(ResultSet rs, Statement stm) throws SQLException {
        if (rs != null) {
            rs.close();
        }
        if

补充：软件开发 , Java ,