Spring注解 TX声明式事务实现过程解析

<!--spring提供的数据库操作工具-->
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-jdbc</artifactId>
  <version>5.0.2.RELEASE</version>
</dependency>
<!--c3p0 数据库连接池-->
<dependency>
  <groupId>com.mchange</groupId>
  <artifactId>c3p0</artifactId>
  <version>0.9.5.5</version>
</dependency>
<!--mysql连接器-->
<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>5.1.48</version>
</dependency>

@Configuration
@ComponentScan("com.spring.tx")
public class TxConfig {
  /**
   * 配置数据源
   */
  @Bean
  public DataSource dataSource() throws PropertyVetoException {
    ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
    comboPooledDataSource.setUser("root");
    comboPooledDataSource.setPassword("root");
    comboPooledDataSource.setDriverClass("com.mysql.jdbc.Driver");
    comboPooledDataSource.setJdbcUrl("jdbc:mysql:///test");
    return comboPooledDataSource;
  }

  @Bean
  public JdbcTemplate jdbcTemplate() throws PropertyVetoException {
    //Spring对配置类做了特殊处理，多次调用给容器中加组件的方法，其实是从容器中找组件，并不会重新添加
    return new JdbcTemplate(dataSource());
  }
}

@Repository
public class UserDao {
  @Autowired
  private JdbcTemplate jdbcTemplate;

  public void saveUser(String name, Integer age) {
    String sql = "insert into user(name, age) values(?, ?)";
    jdbcTemplate.update(sql, name, age);
  }
}

@Service
public class UserService {
  @Autowired
  private UserDao userDao;

  public void saveUser(){
    String name = "jack11";
    Integer age = 19;
    userDao.saveUser(name, age);
  }
}

public class TxTest {
  @Test
  public void test(){
    ApplicationContext context = new AnnotationConfigApplicationContext(TxConfig.class);
    UserService userService = (UserService) context.getBean("userService");
    userService.saveUser();
  }
}

@Transactional
public void saveUser(){
  String name = "jack11";
  Integer age = 19;
  userDao.saveUser(name, age);
  //模拟异常
  int i = 1 / 0;
}

@Configuration
@ComponentScan("com.spring.tx")
@EnableTransactionManagement
public class TxConfig {
	//省略数据源、jdbcTemplate的配置
}

/**
 * 注册事务管理器
 */
@Bean
public PlatformTransactionManager platformTransactionManager() throws PropertyVetoException {
  return new DataSourceTransactionManager(dataSource());
}