[Java知识库]Spring中哪些注解可以声明一个Bean和Spring事务

常用的Bean注解，通过注解定义Bean

1. .@Component.
2. @Repository.
3. @Service.
4. @Controller
5. ·@RestController
   ?

Spring事务

一致的事务模型，屏蔽差异性。
· JDBC/Hibernate/myBatis
. DataSource/JTA

?传播特性

?事务隔离级别

Spring默认以数据库的隔离级别为准，默认值-1；

?Spring编程式事务

@SpringBootApplication
@Slf4j
public class ProgrammaticTransactionDemoApplication implements CommandLineRunner {
	@Autowired
	private TransactionTemplate transactionTemplate;
	@Autowired
	private JdbcTemplate jdbcTemplate;

	public static void main(String[] args) {
		SpringApplication.run(ProgrammaticTransactionDemoApplication.class, args);
	}

	@Override
	public void run(String... args) throws Exception {
		log.info("COUNT BEFORE TRANSACTION: {}", getCount());
		transactionTemplate.execute(new TransactionCallbackWithoutResult() {
			@Override
			protected void doInTransactionWithoutResult(TransactionStatus transactionStatus) {
				jdbcTemplate.execute("INSERT INTO FOO (ID, BAR) VALUES (1, 'aaa')");
				log.info("COUNT IN TRANSACTION: {}", getCount());
				transactionStatus.setRollbackOnly();
			}
		});
		log.info("COUNT AFTER TRANSACTION: {}", getCount());
	}

	private long getCount() {
		return (long) jdbcTemplate.queryForList("SELECT COUNT(*) AS CNT FROM FOO")
				.get(0).get("CNT");
	}
}

?Spring声明式事务

事务失效：?默认情况下，只有来自外部的方法调用才会被AOP代理捕获，也就是，类内部方法调用本类内部的其他方法并不会引起事务行为，必须是代理对象调用才可以！即使被调用方法使用@Transactional注解进行修饰。

?

?

@Component
public class FooServiceImpl implements FooService {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    @Transactional
    public void insertRecord() {
        jdbcTemplate.execute("INSERT INTO FOO (BAR) VALUES ('AAA')");
    }

    @Override
    @Transactional(rollbackFor = RollbackException.class)
    public void insertThenRollback() throws RollbackException {
        jdbcTemplate.execute("INSERT INTO FOO (BAR) VALUES ('BBB')");
        throw new RollbackException();
    }

    @Override
    public void invokeInsertThenRollback() throws RollbackException {
        insertThenRollback(); // 事务失效，内部调用而非代理调用，解决，FooServiceImpl自己注入自己
    }
}

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