【java基础知识】通过java实时查询数据库

网上查到通过java使用定时器实现每2秒查询一次数据库。本人菜鸟，还得多学习呀。

附上转载链接：https://blog.csdn.net/liangayang/article/details/82850593

这个还没有亲测，由于时间紧张，先记下来，以后会用到的。

1.起定时器，每2秒进行一次动作

package connection;
 
import java.util.Timer;
import java.util.TimerTask;
 
public class ConnetionToOracle extends TimerTask {
	public static void main(String[] args) {
		Timer timer = new Timer();      //起定时器，每2秒查询一次
		ConnetionToOracle t = new ConnetionToOracle();
		timer.schedule(t, 0, 2000);
	}
 
	@Override
	public void run() {
		// TODO Auto-generated method stub
		JdbcConnection.JdbcDemo();  //调用方法
	}
 
}

2、查询数据库（上述主程序调用的类）

package connection;
 
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
 
public class JdbcConnection {
	
	public static void JdbcDemo() {
        Connection con;
        String driver = "oracle.jdbc.OracleDriver";
        String url = "jdbc:oracle:thin:@。。。。";
        String user = "";
        String password = "";
        try {
            Class.forName(driver);
            con = DriverManager.getConnection(url,user,password);
            if(!con.isClosed())
                System.out.println("Succeeded connecting to the Database!");
            Statement statement = con.createStatement();
            String sql = "select * from t_users";
            ResultSet rs = statement.executeQuery(sql);
            System.out.println("-----------------");
            System.out.println("执行结果如下所示:");  
            System.out.println("-----------------");  
            System.out.println("姓名" + "\t" + "ID");  
            System.out.println("-----------------");  
             
            String username = null;
            String user_id = null;
            while(rs.next()){
                username = rs.getString("USERNAME");
                user_id = rs.getString("USER_ID");
                System.out.println(username + "\t" + user_id);
            }
            rs.close();
            con.close();
        } catch(ClassNotFoundException e) {   
            //数据库驱动类异常处理
            System.out.println("数据库连接失败");   
            e.printStackTrace();   
            } catch(SQLException e) {
            //数据库连接失败异常处理
            	 System.out.println("数据库连接失败");  
            }catch (Exception e) {
            // TODO: handle exception
            	 System.out.println("数据库连接失败");
        }finally{
            System.out.println("数据库数据成功获取！！");
        }
    }
}