package com.myit.util;import java.lang.reflect.Field;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.ResultSetMetaData;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;public class DBHelper {    private static final String DRIVER="com.mysql.jdbc";    private static final String URL="jdbc:mysql://localhost:3306/dvd";    private static final String USER="root";    private static final String PASSWORD="root";        /**     * 连接数据库     * @return 链接数据库对象     */    public Connection getConnection(){        Connection conn=null;        try {            Class.forName(DRIVER);        } catch (ClassNotFoundException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        try {            conn=DriverManager.getConnection(URL, USER, PASSWORD);        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        return conn;    }        /**     * 释放相应的资源     * @param rs     * @param pstmt     * @param conn     */    public void closeAll(ResultSet rs,PreparedStatement pstmt,Connection conn){        try {            if(rs!=null){                rs.close();            }            if(pstmt!=null){                pstmt.close();            }            if(conn!=null){                conn.close();            }        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }        /**     * 此方法可以完成增删改所有的操作     * @param sql     * @param params     * @return true or false     */    public boolean excuteUpdate(String sql,List