Java 事务教程-测试回滚

我试图学习如何在JavaSpring中使用事务。我是一名java新手，请耐心听我说：-）我试图实现的单元测试是测试： 如果引发运行时异常，则回滚

我遇到的问题是 java.lang.NullPointerException

好了，开始。。我删去了一些代码以帮助提高可读性

TutorialTest.java

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = AppConfig.class, loader=AnnotationConfigContextLoader.class)
public class TutorialTest {

    @Autowired
    private Dao dao;


    @Test
    public void that_if_a_runtime_exception_is_thrown_transaction_rolledback(){

        User u = new User();
        u.setUsername("FAIL_TEST");
        u.setPhone("0161");
        u.setEmail("FAIL_TEST@gmail.com");
        //dao.addUser(u);  // -- this will insert if uncommented out so I know it works

        OuterService os  = new OuterService();
        os.addUserThrowError(u);

    }
}

@ContextConfiguration(classes = AppConfig.class, loader=AnnotationConfigContextLoader.class)
public class OuterService {

    @Autowired
    private Dao dao;

    @Transactional
    public void addUserThrowError(User user) throws RuntimeException{

        dao.addUser(user);  // gives me a java.lang.NullPointerException?

        throw new RuntimeException("This should roll back DB entry");
    }

}

@Configuration
@EnableTransactionManagement
@ComponentScan(value = {"com.training.spring.tx.tutorial.dao",
                        "com.training.spring.tx.tutorial.service"})
public class AppConfig {

    public DataSource dataSource() {

        // Create a BasicDataSource object and configure database

        BasicDataSource dataSource = new BasicDataSource();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost/spring_training_tx");
        dataSource.setUsername("training");
        dataSource.setPassword("training");

        return dataSource;
    }

    @Bean
    public DataSourceTransactionManager transactionManager() {
        DataSourceTransactionManager transactionManager = new DataSourceTransactionManager();
        transactionManager.setDataSource(dataSource());
        return transactionManager;
    }

    @Bean
    public JdbcTemplate jdbcTemplate(){
        return new JdbcTemplate(transactionManager().getDataSource());
    }

}

OuterService.java

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = AppConfig.class, loader=AnnotationConfigContextLoader.class)
public class TutorialTest {

    @Autowired
    private Dao dao;


    @Test
    public void that_if_a_runtime_exception_is_thrown_transaction_rolledback(){

        User u = new User();
        u.setUsername("FAIL_TEST");
        u.setPhone("0161");
        u.setEmail("FAIL_TEST@gmail.com");
        //dao.addUser(u);  // -- this will insert if uncommented out so I know it works

        OuterService os  = new OuterService();
        os.addUserThrowError(u);

    }
}

@ContextConfiguration(classes = AppConfig.class, loader=AnnotationConfigContextLoader.class)
public class OuterService {

    @Autowired
    private Dao dao;

    @Transactional
    public void addUserThrowError(User user) throws RuntimeException{

        dao.addUser(user);  // gives me a java.lang.NullPointerException?

        throw new RuntimeException("This should roll back DB entry");
    }

}

@Configuration
@EnableTransactionManagement
@ComponentScan(value = {"com.training.spring.tx.tutorial.dao",
                        "com.training.spring.tx.tutorial.service"})
public class AppConfig {

    public DataSource dataSource() {

        // Create a BasicDataSource object and configure database

        BasicDataSource dataSource = new BasicDataSource();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost/spring_training_tx");
        dataSource.setUsername("training");
        dataSource.setPassword("training");

        return dataSource;
    }

    @Bean
    public DataSourceTransactionManager transactionManager() {
        DataSourceTransactionManager transactionManager = new DataSourceTransactionManager();
        transactionManager.setDataSource(dataSource());
        return transactionManager;
    }

    @Bean
    public JdbcTemplate jdbcTemplate(){
        return new JdbcTemplate(transactionManager().getDataSource());
    }

}

豆子是在

AppConfig.java

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = AppConfig.class, loader=AnnotationConfigContextLoader.class)
public class TutorialTest {

    @Autowired
    private Dao dao;


    @Test
    public void that_if_a_runtime_exception_is_thrown_transaction_rolledback(){

        User u = new User();
        u.setUsername("FAIL_TEST");
        u.setPhone("0161");
        u.setEmail("FAIL_TEST@gmail.com");
        //dao.addUser(u);  // -- this will insert if uncommented out so I know it works

        OuterService os  = new OuterService();
        os.addUserThrowError(u);

    }
}

@ContextConfiguration(classes = AppConfig.class, loader=AnnotationConfigContextLoader.class)
public class OuterService {

    @Autowired
    private Dao dao;

    @Transactional
    public void addUserThrowError(User user) throws RuntimeException{

        dao.addUser(user);  // gives me a java.lang.NullPointerException?

        throw new RuntimeException("This should roll back DB entry");
    }

}

@Configuration
@EnableTransactionManagement
@ComponentScan(value = {"com.training.spring.tx.tutorial.dao",
                        "com.training.spring.tx.tutorial.service"})
public class AppConfig {

    public DataSource dataSource() {

        // Create a BasicDataSource object and configure database

        BasicDataSource dataSource = new BasicDataSource();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost/spring_training_tx");
        dataSource.setUsername("training");
        dataSource.setPassword("training");

        return dataSource;
    }

    @Bean
    public DataSourceTransactionManager transactionManager() {
        DataSourceTransactionManager transactionManager = new DataSourceTransactionManager();
        transactionManager.setDataSource(dataSource());
        return transactionManager;
    }

    @Bean
    public JdbcTemplate jdbcTemplate(){
        return new JdbcTemplate(transactionManager().getDataSource());
    }

}

---

首先，引用

@ContextConfiguration

定义用于 确定如何加载和配置的

ApplicationContext

集成测试

考虑一下如何在

OuterService

上使用它。看起来对吗？

OuterService

是否用于加载和配置集成测试的

ApplicationCOntext

？除非我遗漏了一些重要的东西，否则答案是：不

那么什么是

OuterService

？这是一种服务。你好像想把它当豆子用。什么是豆子？bean是一个对象，其生命周期由Spring管理。这包括bean类的实例化、对象的初始化、后处理，最后是对象的销毁

如果像这样创建对象

OuterService os  = new OuterService();

那么春天就不在了。您创建了该对象，而Spring没有办法钩住它。因此，您不能期望Spring自动关联其字段

@Autowired
private Dao dao;

由于您尚未初始化该字段，它仍然是

null

，这会导致

NullPointerException

那么，我们如何获得一个由Spring管理的

OuterService

bean呢？您可以为

OuterService

声明

@Bean

方法，或者使用

@Component

或其任何专门化注释

OuterService

，并对其所在的包进行组件扫描。然后将该bean注入到使用它的任何其他bean中。比如说,

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = AppConfig.class, loader=AnnotationConfigContextLoader.class)
public class TutorialTest {

    @Autowired
    private Dao dao;

    @Autowired
    private OuterService os;

---

然后可以直接使用该变量

Spring不参与

newouterservice（）查看Javadoc。Spring有非常好的文档。
@ContextConfiguration
做什么？你如何在春季申报豆子？嗨，我已经更新了这个问题来帮助改进它。我还从标题中删除了spring。我已经包含了bean声明，答案非常简单：Spring不参与新的OuterService（）；因此不会将任何内容自动关联到该对象中。解释更长。阅读SpringIOC文档，它解释了所有这些。我已经看了文档，我还没有进一步弄清楚我需要做什么？从您的回复中，我想我需要将新的OuterService（）与bean配置链接起来。上面的bean示例是XML格式的，我被告知要学习的不是。。