封装DB

Java代码 
package com.zm.bbs; 
 
import java.sql.Connection; 
import java.sql.DriverManager; 
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"); 
        } catch (ClassNotFoundException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } 
        try { 
            conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/bbs","root","root"); 
        } catch (SQLException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } 
        return conn; 
    } 
     
    public static Statement getStmt(Connection conn){ 
        Statement stmt=null; 
        try { 
            stmt=conn.createStatement(); 
        } catch (SQLException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } 
        return stmt; 
    } 
    public static ResultSet getRs(Statement stmt,String sql){ 
        ResultSet rs=null; 
        try { 
            rs=stmt.executeQuery(sql); 
        } catch (SQLException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } 
        return rs; 
    } 
     
    public static void close(ResultSet rs){ 
        if(rs!=null){ 
            try { 
                rs.close(); 
            } catch (SQLException e) { 
                // TODO Auto-generated catch block 
                e.printSta