jdbc写一个访问数据库的工具类

约定不等于承诺〃 2022-05-11 11:00 197阅读 0赞

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

![70][]

[70]: /images/20220505/951d3a754a584723b9b94c80cd4baeb5.png