JDBC 初步

1.

JDBC  即 java database connection

 

java 与数据库连接的一项技术,就我现在认为的.

 

首先是,要在工作环境上加入,D:/oracle/product/10.1.0/Db_2/jdbc/lib 中的classes12.jar 文件.

 

第二步,下面写一个jdbc 的初步应用小程序好了.

import java.sql.*;public class BlogJDBC {public static void main(String[] args) {Connection conn = null;Statement stmt = null;String sql = null;ResultSet rs = null;try {Class.forName("oracle.jdbc.driver.OracleDriver"); //获取数据库连接的驱动,即载入驱动String url = "jdbc:oracle:thin:@192.168.1.12:1521:orcl";conn = DriverManager.getConnection(url,"scott","tiger");//建立数据库连接,即注册驱动,,, 为固定连接串,@+hostip+端口号+数据库sid//后面两个字符串分别为 数据库的用户名 . 密码stmt = conn.createStatement();//创建Statement对象sql = "select * from dept";rs = stmt.executeQuery(sql);//调用并执行SQL语句while(rs.next()) {System.out.println(rs.getString(1));//访问ResultSet中的记录集并从中取出记录}} catch(ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e1) {e1.printStackTrace();} finally {try {if(rs != null) {rs.close();rs = null;}if(stmt != null) {stmt.close();stmt = null;}if(conn != null) {conn.close();conn = null;}//依次关闭ResultSet、Statement和Connection对象} catch(SQLException e) {e.printStackTrace();}}}} 

 

 

2.

statement 包括 PreparedStatement 和 CallableStatement

 

preparedStatement 能进行如下操作:

pstmt = conn.prepareStatement ("insert into dept2 values (?, ?, ?)");pstmt.setInt(1, deptno);pstmt.setString(2, dname);pstmt.setString(3, loc);pstmt.executeUpdate();

一般编程中多使用preparedStatement

 

CallableStatement 能进行如下操作:

CallableStatement cstmt = conn.prepareCall ("{call p(?, ?, ?, ?)}");cstmt.registerOutParameter(3, Types.INTEGER);cstmt.registerOutParameter(4, Types.INTEGER);cstmt.setInt(1, 3);cstmt.setInt(2, 4);cstmt.setInt(4, 5);cstmt.execute();

 

3.

 

以下是一个批处理的下程序

import java.sql.*;public class TestTransaction {public static void main(String[] args) {Connection conn = null;Statement stmt = null;try {Class.forName("oracle.jdbc.driver.OracleDriver");conn = DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:SXT", "scott", "tiger");conn.setAutoCommit(false);stmt = conn.createStatement();stmt.addBatch("insert into dept2 values (51, '500', 'haha')");stmt.addBatch("insert into dept2 values (52, '500', 'haha')");stmt.addBatch("insert into dept2 values (53, '500', 'haha')");stmt.executeBatch();conn.commit();conn.setAutoCommit(true);} catch (ClassNotFoundException e) {e.printStackTrace();} catch(SQLException e) {e.printStackTrace();try {if(conn != null){conn.rollback();conn.setAutoCommit(true);}} catch (SQLException e1) {e1.printStackTrace();}}finally {try {if(stmt != null)stmt.close();if(conn != null)conn.close();} catch (SQLException e) {e.printStackTrace();}}}}