jdbc不写bean类还能返回查询的结果

_{ResultSetMetaData metaData = rs.getMetaData();}

jdbc中有一步是返回结果集，在结果集中有个getMetaData()的方法就可以得到数据库中的所有值，例如字段名、行数、列数等等可以用debug看看

以下是jdbc的增删改和查的封装类，不用写bean类就可直接使用

package com.hp.factory;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class AllFactory {
   final static String url = "jdbc:mysql://localhost:3306/project01?unicode=true&characterEncoding=UTF-8";
   final static String user = "root";
   final static String password = "root";
   final static String driver = "com.mysql.jdbc.Driver";
   public static Connection getConn()throws Exception {
       Class.forName(driver);
       return DriverManager.getConnection(url, user, password);
   }
   public static List<Map<String, Object>> executeQuery(String sql)throws Exception {
       List<Map<String, Object>> list = new ArrayList<Map<String,Object>>();
       Connection conn = getConn();
       PreparedStatement ps = conn.prepareStatement(sql);
       ResultSet rs = ps.executeQuery();
       while (rs.next()) {
           ResultSetMetaData metaData = rs.getMetaData();
           Map<String, Object> map = new HashMap<String, Object>();
           for(int i=1;i<=metaData.getColumnCount();i++) {
               map.put(metaData.getColumnLabel(i), rs.getObject(i));
           }
           list.add(map);
       }
       rs.close();
       ps.close();
       conn.close();
       return list;
   }
   public static int excuteUpdate(String sql) throws Exception {
       Connection conn = getConn();
       PreparedStatement ps = conn.prepareStatement(sql);
       int i = ps.executeUpdate();
       ps.close();
       conn.close();
       return i;
   }

}