显示SQL SELECT,INSERT,UPDATE和DELETE 的简单Java JDBC例子
Xn_warm
・3 分钟阅读
下面是一个简短的java/JDBC例子程序,其中演示如何使用JDBC执行SQL SELECT
,INSERT
,UPDATE
和DELETE
语句:
package com.devdaily.sqlprocessortests; import java.sql.*; public class BasicJDBCDemo { Connection conn; public static void main(String[] args) { new BasicJDBCDemo(); } public BasicJDBCDemo() { try { Class.forName(\"com.mysql.jdbc.Driver\").newInstance(); String url =\"jdbc:mysql://localhost/coffeebreak\"; conn = DriverManager.getConnection(url,\"username\",\"password\"); doTests(); conn.close(); } catch (ClassNotFoundException ex) {System.err.println(ex.getMessage());} catch (IllegalAccessException ex) {System.err.println(ex.getMessage());} catch (InstantiationException ex) {System.err.println(ex.getMessage());} catch (SQLException ex) {System.err.println(ex.getMessage());} } private void doTests() { doSelectTest(); doInsertTest(); doSelectTest(); doUpdateTest(); doSelectTest(); doDeleteTest(); doSelectTest(); } private void doSelectTest() { System.out.println(\"[OUTPUT FROM SELECT]\"); String query =\"SELECT COF_NAME, PRICE FROM COFFEES\"; try { Statement st = conn.createStatement(); ResultSet rs = st.executeQuery(query); while (rs.next()) { String s = rs.getString(\"COF_NAME\"); float n = rs.getFloat(\"PRICE\"); System.out.println(s +\"\" + n); } } catch (SQLException ex) { System.err.println(ex.getMessage()); } } private void doInsertTest() { System.out.print(\"n[Performing INSERT] ...\"); try { Statement st = conn.createStatement(); st.executeUpdate(\"INSERT INTO COFFEES\" + \"VALUES (\'BREAKFAST BLEND\', 200, 7.99, 0, 0)\"); } catch (SQLException ex) { System.err.println(ex.getMessage()); } } private void doUpdateTest() { System.out.print(\"n[Performing UPDATE] ...\"); try { Statement st = conn.createStatement(); st.executeUpdate(\"UPDATE COFFEES SET PRICE=4.99 WHERE COF_NAME=\'BREAKFAST BLEND\'\"); } catch (SQLException ex) { System.err.println(ex.getMessage()); } } private void doDeleteTest() { System.out.print(\"n[Performing DELETE] ...\"); try { Statement st = conn.createStatement(); st.executeUpdate(\"DELETE FROM COFFEES WHERE COF_NAME=\'BREAKFAST BLEND\'\"); } catch (SQLException ex) { System.err.println(ex.getMessage()); } } }
此代码使用的数据库为来自Sun's原始JDBC教程的Coffee Break数据库 。