JDBC
The JDBC API is a Java API that can access any kind of tabular data, especially data stored in a Relational Database.
JDBC helps you to write Java applications that manage these three programming activities:
- Connect to a data source, like a database
- Send queries and update statements to the database。
- Retrieve and process the results received from the database in answer to your query
1JDBC - oracle
1.1 Install a JDBC driver from Oracle
现在oracle JDBC驱动器： ojdbc6_g。
将ojdbc6_g放入到项目的lib文件夹中，如下
C:\study\java\jdbc\lib\ojdbc6_g.jar
1.2 eclipse导入驱动器ojdbc6_g
在eclipse中导入如下：
右键点击JDBC项目 ---> Build Path ---> Config Build Path ---> Libraries ---> Add External JARs ---> 输入C:\study\java\jdbc\lib\ojdbc6_g.jar ---> OK
1.3 编写程序测试
package jdbc;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;public class jdbc_exp { public static void main(String[] args) { Connection con = null;// 创建一个数据库连接 PreparedStatement pre = null;// 创建预编译语句对象，一般都是用这个而不用Statement ResultSet result = null;// 创建一个结果集对象 try { Class.forName("oracle.jdbc.driver.OracleDriver");// 加载Oracle驱动程序 System.out.println("开始尝试连接数据库！"); String url = "jdbc:oracle:" + "thin:@0.0.0.188:1521:tonytest";// 127.0.0.1是本机地址，XE是精简版Oracle的默认数据库名 String user = "hr";// 用户名,系统默认的账户名 String password = "CCM%lab123";// 你安装时选设置的密码 con = DriverManager.getConnection(url, user, password);// 获取连接 System.out.println("连接成功！"); String sql = "select * from dept order by 1";// 预编译语句，“？”代表参数 pre = con.prepareStatement(sql);// 实例化预编译语句 result = pre.executeQuery();// 执行查询，注意括号中不需要再加参数 while (result.next()) // 当结果集不为空时 System.out.println("deptno: " + result.getInt("deptno") + " dname: " + result.getString("dname") + " loc: " + result.getString("loc") + " create_date: " + result.getString("create_date")); } catch (Exception e) { e.printStackTrace(); } finally { try { // 逐一将上面的几个对象关闭，因为不关闭的话会影响性能、并且占用资源 // 注意关闭的顺序，最后使用的最先关闭 if (result != null) result.close(); if (pre != null) pre.close(); if (con != null) con.close(); System.out.println("数据库连接已关闭！"); } catch (Exception e) { e.printStackTrace(); } } }}