Java连接数据库jdbc

Posted 2022-09-28 hpha

java连接数据库

import java.sql.*;
public class Jdbc05 
    static final String URL="jdbc:mysql://localhost:3306/test";
    static final String USER="root";
    static final String PWD="root";
    public static void main(String[] args) 
  //定义sql语句     
        String s="select id,account,balance from bank where id=1";
        
        Connection conn=null;
        Statement statement=null;
        ResultSet resultSet=null;
        try 
//注册驱动
            Class.forName("com.mysql.jdbc.Driver");
//获取数据库连接对象
            conn= DriverManager.getConnection(URL,USER,PWD);
//获取执行sql的对象statement
            statement= conn.createStatement();
//执行sql
            resultSet= statement.executeQuery(s);
　　　　　　if(resultSet.next==false)
　　　　　　　　System.out.println("列表中没有查询项");
            
                resultSet.previous();//回到前一项数据,对上if的回溯
   //循环读取
                    while(resultSet.next())
　　　　//获取每一行的各列 的值
                        int ID=resultSet.getInt(1);
                        String account=resultSet.getString(2);
                        int balance=resultSet.getInt(3);
                        System.out.println(ID+"\t"+account+"\t"+balance);
                    
         catch (SQLException e) 
            e.printStackTrace();
         catch (ClassNotFoundException e) 
            e.printStackTrace();
         finally //关闭释放内存
            if(resultSet!=null)
                try 
                    resultSet.close();
                 catch (SQLException e) 
                    e.printStackTrace();
                
            
            if(statement!=null)
                try 
                    statement.close();
                 catch (SQLException e) 
                    e.printStackTrace();
                
            
            if(conn!=null)
                try 
                    conn.close();
                 catch (SQLException e) 
                    e.printStackTrace();