杭州电商网站平台开发公司,贵州三线建设博物馆网站,网站结构化数据,云匠网描述当我们需要在Java程序中与数据库进行交互#xff0c;可能首先想到的是使用某个ORM框架#xff0c;因为ORM框架封装了一些实现细节#xff0c;在使用上非常方便#xff0c;并且一定程度上可以提升代码稳定性。在ORM框架中#xff0c;都会依赖MySQL Connector包#xf…描述当我们需要在Java程序中与数据库进行交互可能首先想到的是使用某个ORM框架因为ORM框架封装了一些实现细节在使用上非常方便并且一定程度上可以提升代码稳定性。在ORM框架中都会依赖MySQL Connector包因为真正与数据库进行交互的是在MySQL Connector包里面实现。5.x版本maven依赖mysqlmysql-connector-java5.1.47三种方式MySQL Connector执行SQL语句主要有executeQueryexecuteUpdateexecute等三种方式。executeQuery此方法执行Selec查询语句通过ResultSet返回结果集。private static void executeQuery() throws Exception{Connection connection null;Statement statement null;ResultSet rs null;try {connection DriverManager.getConnection(url);statement connection.createStatement();statement.setFetchSize(Integer.MIN_VALUE);String sql select * from user;rs statement.executeQuery(sql);int count0;while (rs.next()){count;}System.out.println(executeQuery count: count);} catch (Exception e){e.printStackTrace();} finally {close(connection,statement,rs);}}executeUpdate此方法执行InsertUpdateDelete语句返回变更影响的行数。private static void executeUpdate() throws Exception{Connection connection null;Statement statement null;int updateCount 0;try {connection DriverManager.getConnection(url);statement connection.createStatement();String sql update user set name啊啊啊 where id new Random().nextInt(999999);updateCount statement.executeUpdate(sql);System.out.println(executeUpdate count: updateCount);} catch (Exception e){e.printStackTrace();} finally {close(connection,statement,null);}}execute当我们不知道来源SQL是Select查询还是Insert/Update/Delete更新时可以统一使用excute()方法来执行SQL语句此方法返回一个boolean值如果返回true表示执行的SQL语句为Select查询语句此时可以通过Statement#getResultSet()方法来获取结果集如果返回false表示执行的时Insert/Update/Delete语句此时可以通过Statement#getUpdateCount()来返回此次SQL执行对数据库影响的行数。private static void executeForSelect() throws Exception{Connection connection null;Statement statement null;ResultSet rs null;try {connection DriverManager.getConnection(url);statement connection.createStatement();statement.setFetchSize(Integer.MIN_VALUE);String sql select * from user;if (statement.execute(sql)){rs statement.getResultSet();}int count0;while (rs.next()){count;}System.out.println(executeForSelect count: count);} catch (Exception e){e.printStackTrace();} finally {close(connection,statement,rs);}}private static void executeForUpdate() throws Exception{Connection connection null;Statement statement null;int updateCount 0;try {connection DriverManager.getConnection(url);statement connection.createStatement();String sql update user set name啊啊啊 where id new Random().nextInt(999999);if (!statement.execute(sql)){updateCount statement.getUpdateCount();}System.out.println(executeForUpdate updateCount: updateCount);} catch (Exception e){e.printStackTrace();} finally {close(connection,statement,null);}}验证执行测试public static void main(String[] args) throws Exception {Long start System.currentTimeMillis();executeForSelect();System.out.println(executeForSelect 耗时 (System.currentTimeMillis() - start) ms \n);start System.currentTimeMillis();executeForUpdate();System.out.println(executeForUpdate 耗时 (System.currentTimeMillis() - start) ms \n);start System.currentTimeMillis();executeQuery();System.out.println(executeQuery 耗时 (System.currentTimeMillis() - start) ms \n);start System.currentTimeMillis();executeUpdate();System.out.println(executeUpdate 耗时 (System.currentTimeMillis() - start) ms \n);}private static void close(Connection connection, Statement statement, ResultSet rs) throws Exception{if (rs ! null){rs.close();}if (statement ! null){statement.close();}if (connection ! null){connection.close();}}返回结果executeForSelect count: 4717924executeForSelect 耗时 4791 msexecuteForUpdate updateCount: 1executeForUpdate 耗时 6 msexecuteQuery count: 4717924executeQuery 耗时 4340 msexecuteUpdate count: 1executeUpdate 耗时 8 ms
