oracle_jdbc_Query

本例子程序是根据马士兵老师所讲+自己的注释。写的比较全面，特别是最后释放资源的代码。

package com.ayang.jdbc;

import java.sql.*;

public class TestJDBC {

    
    public static void main(String[] args)  {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try{
        //1、注册驱动
        //new oracle.jdbc.driver.OracleDriver();
        Class.forName("oracle.jdbc.driver.OracleDriver");
        //2、建立连接
        conn = DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:ORCL","scott", "root");
        //3、创建语句
        stmt = conn.createStatement();
        //4、执行语句
        rs = stmt.executeQuery("select * from dept2");
        System.out.println("deptno    ||dname        ||location");
        //5、处理结果
        while(rs.next()){
            System.out.println(rs.getString("deptno")+"    "+rs.getString("dname")+"    "+rs.getString("loc"));
        }
        }catch (ClassNotFoundException e) {
            System.out.println("未正常加载jdbc驱动");
            e.printStackTrace();
        }catch(SQLException e){
            e.printStackTrace();  //log for java
            
        }finally{
        //6、释放资源
        try {
            if(rs != null){  //如果rs没有初始化，这肯定报exception，故判断一下
                rs.close();
                rs = null;   //垃圾回收随时可以回收
            }if(stmt != null){
                stmt.close();
                stmt = null;
            }if(conn != null){
                conn.close();
                conn = null;
            }
        } catch (SQLException e) {
                e.printStackTrace();
        }
        
        
        }
    }

}

欢迎关注个人公众号一起交流学习：