JDBC使用方法的封装

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package cn.com.bochy.Util;

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

/**
* Jdbc工具类
* @author Administrator
*
*/
/**
* 准备工作：将指定的数据库驱动程序构建到当前项目中
* 1.加载驱动
* 2.创建连接
*
*/
public class DBUtil {

private static Connection conn = null;private static PreparedStatement psmt = null;private static ResultSet rs = null;private static int i;private static String url = "jdbc:mysql:///shool";private static String user = "root";private static String password = "admin";//加载驱动static{    try {        Class.forName("com.mysql.jdbc.Driver");    } catch (ClassNotFoundException e) {        e.printStackTrace();    }}   //连接数据库public static Connection getConnection(){    try {        conn = DriverManager.getConnection(url, user, password);    } catch (SQLException e) {        e.printStackTrace();    }    return conn;}/** *  * @param sql 执行查询的sql语句    select * from student where s_name = ? and s_pwd = ? * @param obj[] 查询语句中的条件参数 Object obj[] = {"root","admin"}; * @return *///公共的查询方法(带条件或不带条件的查询)public static ResultSet getQuery(String sql,Object obj[]){    //获取连接    conn = getConnection();    try {    //获取代表sql语句的对象    psmt = conn.prepareStatement(sql);    //如果obj中有参数，则将参数设置到占位符中(?)    if(obj!=null){        for(int in=1;in<=obj.length;in++){            psmt.setObject(in, obj[in-1]);        }    }    //执行查询操作    rs = psmt.executeQuery();    } catch (SQLException e) {        e.printStackTrace();    }    return rs;}//公共的修改 删除 添加方法(带条件或不带条件的查询)    public static int getUpdate(String sql,Object obj[]){        //获取连接        conn = getConnection();        try {        //获取代表sql语句的对象        psmt = conn.prepareStatement(sql);        //如果obj中有参数，则将参数设置到占位符中(?)        if(obj!=null){            for(int in=1;in<=obj.length;in++){                psmt.setObject(in, obj[in-1]);            }        }        //执行查询操作        i = psmt.executeUpdate();        } catch (SQLException e) {            e.printStackTrace();        }        return i;    }//释放资源    public static void Close(){        if(rs!=null){            try {                rs.close();            } catch (SQLException e) {                e.printStackTrace();            }           rs = null;        }        if(psmt!=null){            try {                psmt.close();            } catch (SQLException e) {                e.printStackTrace();            }            psmt = null;        }        if(conn!=null){            try {                conn.close();            } catch (SQLException e) {                e.printStackTrace();            }            conn = null;        }    }

}

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