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();
         }

         }
     }

 }