Hashtable映射数据库字段

package com.test;

import java.sql.*;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
public class Test{
    // 驱动
    String driver = "com.mysql.jdbc.Driver";
    // 数据库连接
    String url = "jdbc:mysql://localhost:3306/ceshi?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&transformedBitIsBoolean=true";
    // 用户名
    String user = "root";
    // 数据库密码
    String password = "hotlon";
    // 加载驱动
    
    List<Hashtable<String, Object>> rows ;
    
    public List<Hashtable<String, Object>> queSql(){
        
        try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        // 获取链接
        Connection connection = null;
        try {
            connection = DriverManager.getConnection(url, user, password);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        // 创建查询声明
        PreparedStatement preparedStatement = null;
        try {
            preparedStatement = connection.prepareStatement("select * from renyuan");
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        // 获取结果
        ResultSet resultSet = null;
        try {
            resultSet = preparedStatement.executeQuery();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        // 获取各个列的信息
        ResultSetMetaData metaData = null;
        try {
            metaData = resultSet.getMetaData();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        // 一条数据保存在一个Hashtable 将所有Hashtable存放到list
        rows = new ArrayList<Hashtable<String, Object>>();
        try {
            while (resultSet.next()) {
                Hashtable<String, Object> row = new Hashtable<String, Object>();
                for (int i = 1; i <= metaData.getColumnCount(); i++) {
                    // 打印列名
                    //System.out.println(metaData.getColumnName(i));
                    //System.out.println(row.get(metaData.getColumnName(i)));
                    row.put(metaData.getColumnName(i), resultSet.getObject(i)==null?"":resultSet.getObject(i));
                    //System.out.println(row.get(metaData.getColumnName(i)));
                    }
                rows.add(row);
                }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        try {
            resultSet.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        try {
            preparedStatement.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        try {
            connection.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        
        //System.out.println(rows.get(1).get("uid"));
        return rows;

    }
    
    
    
    public static void main(String[] args) throws Exception {
        
        Test test = new Test();
        System.out.println(test.queSql().get(1).get("uid"));
        
        
        }
    }