JDBC默认是自动提交，事务是关闭的，statement|preparedStatement.executeUpdate()或excute()执行增删改，执行一次就提交一次（自动同步到数据库）。

 

JDBC事务示例：

 1  //从properties文件中加载数据库配置
 2         Properties properties = new Properties();
 3         InputStream inputStream =Class.forName("test.Test").getResourceAsStream("/mysql.properties");
 4         properties.load(inputStream);
 5 
 6         String driver = properties.getProperty("driver");
 7         String url = properties.getProperty("url");
 8         String user = properties.getProperty("user");
 9         String pwd=properties.getProperty("password");
10 
11         Class.forName(driver);
12         Connection connection = DriverManager.getConnection(url, user, pwd);
13         connection.setAutoCommit(false);   //关闭自动提交，此句代码会自动开启事务。默认为true，自动提交。
14 
15         String sql1 = "insert into student_tb (name,age,score) values (?,?,?)";
16         PreparedStatement preparedStatement1 = connection.prepareStatement(sql1);
17         preparedStatement1.setString(1,"chy");
18         preparedStatement1.setInt(2,20);
19         preparedStatement1.setInt(3,100);
20         preparedStatement1.executeUpdate();  //放置到队列中
21 
22         String sql2 = "update student_tb set name=? where id=?";
23         PreparedStatement preparedStatement2 = connection.prepareStatement(sql2);
24         preparedStatement2.setString(1,"CoCo");
25         preparedStatement2.setInt(2,10);
26         preparedStatement2.executeUpdate();  //放置到队列中
27 
28         try{
29             connection.commit();   //提交事务
30         }catch (SQLException e){
31             connection.rollback();  //失败就回滚
32         } finally {
33             preparedStatement1.close();
34             preparedStatement2.close();
35             connection.close();
36         }