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。

 1 package com.ayang.jdbc;
 2
 3 import java.sql.*;
 4
 5 public class TestJDBC {
 6
 7
 8     public static void main(String[] args)  {
 9         Connection conn = null;
10         Statement stmt = null;
11         ResultSet rs = null;
12         try{
13         //1、注册驱动
14         //new oracle.jdbc.driver.OracleDriver();
15         Class.forName("oracle.jdbc.driver.OracleDriver");
16         //2、建立连接
17         conn = DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:ORCL","scott", "root");
18         //3、创建语句
19         stmt = conn.createStatement();
20         //4、执行语句
21         rs = stmt.executeQuery("select * from dept2");
22         System.out.println("deptno    ||dname        ||location");
23         //5、处理结果
24         while(rs.next()){
25             System.out.println(rs.getString("deptno")+"    "+rs.getString("dname")+"    "+rs.getString("loc"));
26         }
27         }catch (ClassNotFoundException e) {
28             System.out.println("未正常加载jdbc驱动");
29             e.printStackTrace();
30         }catch(SQLException e){
31             e.printStackTrace();  //log for java
32
33         }finally{
34         //6、释放资源
35         try {
36             if(rs != null){  //如果rs没有初始化，这肯定报exception，故判断一下
37                 rs.close();
38                 rs = null;   //垃圾回收随时可以回收
39             }if(stmt != null){
40                 stmt.close();
41                 stmt = null;
42             }if(conn != null){
43                 conn.close();
44                 conn = null;
45             }
46         } catch (SQLException e) {
47                 e.printStackTrace();
48         }
49
50
51         }
52     }
53
54 }