JDBC工具类（DButil）

package lesson11;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.sql.Statement;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;public class DBUtil {	private Connection conn = null;	private Statement st = null;	private PreparedStatement ps = null;	private ResultSet rs = null;	private String url = "jdbc:mysql://localhost:3306/filmcenter_db";	private String useame = "root";	private String psw = "root";	

//1.加载驱动static{	try {		Class.forName("com.mysql.jdbc.Driver");	} catch (ClassNotFoundException e) {		System.out.println("加载驱动失败！！");		e.printStackTrace();	}}//2.获取连接public Connection getConn(){	try {		conn = DriverManager.getConnection(url,useame,psw);	} catch (SQLException e) {		System.out.println("获取连接失败！！");		e.printStackTrace();	}	retu conn;}//3.提供更新方法public int update(String sql, Object[] objs){	conn = getConn();	try {		ps = conn.prepareStatement(sql);		for(int i = 0 ; i < objs.length ; i ++){			ps.setObject(i + 1, objs[i]);		}		retu ps.executeUpdate();	} catch (SQLException e) {		System.out.println("更新失败！！");		e.printStackTrace();		retu -1;	}finally{		release();	}}//4.提供查询方法public List<Map<String,Object>> query(String sql, Object[] objs){	List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();	try {		ps = getConn().prepareStatement(sql);		for(int i = 0 ; i < objs.length ; i ++){			ps.setObject(i + 1, objs[i]);		}		rs = ps.executeQuery();		ResultSetMetaData rsmd = rs.getMetaData();		while(rs.next()){			Map<String,Object> map = new HashMap<String,Object>();			for(int i = 0 ; i < rsmd.getColumnCount() ; i ++){				String key = rsmd.getColumnName(i + 1);				Object value = rs.getObject(key);				map.put(key, value);			}			list.add(map);		}		retu list;	} catch (SQLException e) {		System.out.println("查询操作失败！");		e.printStackTrace();		retu list;	}finally{		release();	}}//5.批量更新public void batch(String[] sqls){	try {		conn = getConn();		conn.setAutoCommit(false);		st = conn.createStatement();		for(int i = 0; i < sqls.length ; i ++){			st.addBatch(sqls[i]);		}		st.executeBatch();	} catch (SQLException e) {		e.printStackTrace();		try {			conn.rollback();		} catch (SQLException e1) {			e1.printStackTrace();		}	}finally{		try {			conn.commit();		} catch (SQLException e) {			e.printStackTrace();		}		release();	}}//释放资源public void release(){	if(rs != null){		try {			rs.close();		} catch (SQLException e) {			System.out.println("关闭结果集对象出现异常！");			e.printStackTrace();		}	}	if(ps != null){		try {			ps.close();		} catch (SQLException e) {			System.out.println("关闭预处理语句对象出现异常！");			e.printStackTrace();		}	}	if(st != null){		try {			st.close();		} catch (SQLException e) {			System.out.println("关闭语句对象出现异常！");			e.printStackTrace();		}	}	if(conn != null){		try {			conn.close();		} catch (SQLException e) {			System.out.println("关闭连接对象出现异常！");			e.printStackTrace();		}	}}

}