jdbc写一个访问数据库的工具类

操作的工具类

package com.zjw.jdbc2;
/**
 * jdbc操作的工具类
 * @author Administrator
 *
 */

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

public class JdbcUtils
{
	private JdbcUtils() {}
	
	private static String url = "jdbc:mysql://localhost:3306/aaa?useSSL=false&serverTimezone=UTC";
	private static String user = "root" ;
	private static String password = "123456";
	
	public static Connection getConnection() 
	{
		Connection con = null;
		try
		{
			//加载驱动
			Class.forName("com.mysql.cj.jdbc.Driver");
			//获取连接
			con = DriverManager.getConnection(url, user, password);
		} catch (ClassNotFoundException | SQLException e)
		{
			e.printStackTrace();
		}
		//返回连接结果
		return con;
	}
	/**
	 *  关闭连接 包含三个参数
	 * @param con 连接对象
	 * @param sta Statement对象
	 * @param res 结果集对象
	 */
	public static void closeConnection(Connection con,Statement sta,ResultSet res) 
	{
		try
		{
			if(res != null)
			res.close();
		} catch (SQLException e)
		{
			e.printStackTrace();
		}
		try
		{
			if(sta != null)
			sta.close();
		} catch (SQLException e)
		{
			e.printStackTrace();
		}
		try
		{
			if(con != null)
			con.close();
		} catch (SQLException e)
		{
			e.printStackTrace();
		}
	}
	/**
	 * 关闭连接 包含两个参数
	 * @param con 连接对象
	 * @param sta Statement对象
	 */
	public static void closeConnection(Connection con,Statement sta) 
	{
		try
		{
			if(sta != null)
			sta.close();
		} catch (SQLException e)
		{
			e.printStackTrace();
		}
		try
		{
			if(con != null)
			con.close();
		} catch (SQLException e)
		{
			e.printStackTrace();
		}
	}
}

 利用工具类来操作数据库

package com.zjw.jdbc2;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
 * 使用jdbc编写的工具类操作数据库
 * @author Administrator
 *
 */
public class JdbcUtilTest
{
	public static void main(String[] args)
	{
		//获取连接
		Connection con = JdbcUtils.getConnection();
		//操作数据库
		String sql = "SELECT * FROM category;";
		try
		{
			PreparedStatement pst = con.prepareStatement(sql);
			ResultSet res = pst.executeQuery();
			while(res.next())
			{
				String sid = res.getString("sid");
				String sname = res.getString("sname");
				System.out.println(sid+ " "+ sname);
			}
			//关闭连接
			JdbcUtils.closeConnection(con, pst, res);
		} catch (SQLException e)
		{
			e.printStackTrace();
		}
	}
}

结果