链接数据库程序

[ytyytryrtyryr]

新手
我看不明白这个DB.java程序
可不可帮我在旁边加上注释
谢谢各位好汉！！

package org.bs.utils;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DB {
	public static Connection getConn() {
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e1) {
			e1.printStackTrace();
		}    
		String url = "jdbc:mysql://localhost/database?useUnicode=true&characterEncoding=utf8";
		Connection conn = null;
		try {
			conn = DriverManager.getConnection(url, "root", "root");
			conn.setAutoCommit(false);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return conn;
	}

	public static void close(PreparedStatement pstmt) {
		if (pstmt != null) {
			try {
				pstmt.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}

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

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

	public static void commit(Connection conn) {
		if (conn != null) {
			try {
				conn.commit();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}

	public static void rollback(Connection conn) {
		if (conn != null) {
			try {
				conn.rollback();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
}

另外可不可告诉我这个JDBCHandler.java 程序的作用功能

package org.bs.utils;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.Connection;

public class JDBCHandler<T> implements InvocationHandler {

	private T target = null;

	public T createProxy(Object target) {
		this.target = (T) target;
		return (T) Proxy.newProxyInstance(target.getClass().getClassLoader(),
				target.getClass().getInterfaces(), this);
	}

	public Object invoke(Object proxy, Method method, Object[] args)
			throws Throwable {
		Connection conn = ConnContext.getConn();
		Object result = null;
		try {
			result = method.invoke(target, args);
			DB.commit(conn);
		} catch (Exception e) {
			DB.rollback(conn);
			e.printStackTrace();
		} finally {
			DB.close(conn);
		}
		ConnContext.remove();
		return result;
	}
}

[wonezm]

这是数据库驱动加载、数据库连接、数据库查询返回、一些相关对象关闭设置，你可以百度下java.编写数据库连接代码

[ytyytryrtyryr]

那JDBCHandler.java 这个程序有什么用呢

[EverWHL]

初始化,提交事务,失败回滚