DB封装_MySQL

import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class DB {	public static Connection getConn() {		Connection conn = null;		try {			Class.forName("com.mysql.jdbc.Driver");			conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bbs", "root" , "root");		} catch (ClassNotFoundException e) {			e.printStackTrace();		} catch (SQLException e) {			e.printStackTrace();		}		return conn;	}		public static Statement createStmt(Connection conn) {		Statement stmt = null;		try {			stmt = conn.createStatement();		} catch (SQLException e) {			e.printStackTrace();		}		return stmt;	}		public static ResultSet executeQuery(Statement stmt, String sql) {		ResultSet rs = null;		try {			rs = stmt.executeQuery(sql);		} catch (SQLException e) {			e.printStackTrace();		}		return rs;	}		/*public static ResultSet executeQuery(Connection conn, String sql) {		Statement stmt = null;		ResultSet rs = null;		try {			stmt = conn.createStatement();			rs = stmt.executeQuery(sql);		} catch (SQLException e) {			e.printStackTrace();		}		//		finally {//			close(stmt);//		}						return rs;	}*/		public static int executeUpdate(Connection conn, String sql) {		int ret = 0;		Statement stmt = null;		try {			stmt = conn.createStatement();			ret = stmt.executeUpdate(sql);		} catch (SQLException e) {			e.printStackTrace();		} finally {			close(stmt);		}		return ret;	}		public static PreparedStatement prepareStmt(Connection conn, String sql) {		PreparedStatement pstmt = null;		try {			pstmt = conn.prepareStatement(sql);		} catch (SQLException e) {			e.printStackTrace();		}		return pstmt;	}		public static PreparedStatement prepareStmt(Connection conn, String sql, int autoGeneratedKeys) {		PreparedStatement pstmt = null;		try {			pstmt = conn.prepareStatement(sql, autoGeneratedKeys);		} catch (SQLException e) {			e.printStackTrace();		}		return pstmt;	}		public static void close(Connection conn) {		if(conn != null) {			try {				conn.close();			} catch (SQLException e) {				e.printStackTrace();			}			conn = null;		}	}		public static void close(Statement stmt) {		if(stmt != null) {			try {				stmt.close();			} catch (SQLException e) {				e.printStackTrace();			}			stmt = null;		}	}		public static void close(ResultSet rs) {		if(rs != null) {			try {				rs.close();			} catch (SQLException e) {				e.printStackTrace();			}			rs = null;		}	}}