mysql连接jdbc查询代码

package com.answer.test;

import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.Statement;

public class ConnToMySql {

    public static final String url = "jdbc:mysql://localhost/my_db";
    
    public static final String userName = "root";
    
    public static final String password = "root";
    
    public static void main(String[] args) {
        
        Connection conn = null;
        
        Statement stmt = null;
        
        ResultSet rs = null;
        
        try {
            Class.forName("com.mysql.jdbc.Driver");
            
            conn = (Connection) DriverManager.getConnection(url, userName, password);
            
            stmt = (Statement) conn.createStatement();
            
            String sql = "select * from sys_user";
            
            rs = stmt.executeQuery(sql);    //查
//　　　　　　　　    stmt.executeUpdate(sql); //增删改
            
            while (rs.next()) {
                System.out.println("按照列下标:" + rs.getInt(1));
                System.out.println("按照列名:" + rs.getInt("userID"));
            }
            
        } catch (Exception e) {
            System.out.println("first:" + e);
        } finally {
            try {
                if (null != rs) {
                    rs.close();
                }
                if (null != stmt) {
                    stmt.close();
                }
                if (null != conn) {
                    conn.close();
                }
            } catch (SQLException e) {
                System.out.println("second:" + e);
            }
        }
        
    }
}