spring中@Transactional注解的作用，使用场景举例

一，spring中管理事务一般使用@Transactional 注解，下面对@Transactional 使用的各个场景做一个列举，尽可能的将所有场景罗列出来

1，场景一，最常见的用法，在方法上使用@Transactional 注解，事务正常起作用。无异常时正常提交，有异常时数据回滚，代码如下。

@Service
public class ComeServiceImpl implements ComeService {
    @Autowired
    UserMapper userMapper;
    @Override
    @Transactional
    public int saveUser() {
        User user1 = new User(11,"a",111,"a");
        userMapper.saveUser(user1);
//        int i = 1 / 0;
        User user2 = new User(11,"b",111,"b");
        userMapper.saveUser(user2);
        return 0;
    }
}

2，场景二，常见的用法，在类上使用@Transactional 注解，对整个类的方法，事务起作用。无异常时正常提交，有异常时数据回滚，代码如下。

@Service
@Transactional
public class ComeServiceImpl implements ComeService {
    @Autowired
    UserMapper userMapper;
    @Override
    public int saveUser() {
        User user1 = new User(11,"a",111,"a");
        userMapper.saveUser(user1);
        User user2 = new User(11,"b",111,"b");
        userMapper.saveUser(user2);
        // int i = 1 / 0;
        return 0;
    }
}

3，场景三，将异常信息使用try-catch 包裹，异常被处理，@Transactional 注解不起作用，数据提交，没有回滚，代码如下。

@Service
@Slf4j
public class ComeServiceImpl implements ComeService {
    @Autowired
    UserMapper userMapper;
    @Override
    @Transactional
    public int saveUser() {
        User user1 = new User(11,"a",111,"a");
        userMapper.saveUser(user1);
        User user2 = new User(11,"b",111,"b");
        userMapper.saveUser(user2);
        try {
            int i = 1 / 0;
        }catch (Exception e){
            System.out.println("异常。。。");
        }
        return 0;
    }
}

4，场景四，同一个Service内方法调用，当@Transactional 注解作用在A方法上时，事务起作用。方法A中的数据回滚，方法B中的数据回滚，代码如下。

@Service
@Slf4j
public class ComeServiceImpl implements ComeService {
    @Autowired
    UserMapper userMapper;
    @Override
    @Transactional
    public int A() {
        User user1 = new User(11,"a",111,"a");
        userMapper.saveUser(user1);
        this.B();
        return 0;
    }
    @Override
    public int B() {
        User user2 = new User(11,"b",111,"b");
        userMapper.saveUser(user2);
        int i = 1 / 0;
        return 0;
    }
}

5，场景五，同一个Service内方法调用，当@Transactional 注解作用在B方法上时，事务不起作用。方法A中的数据提交，方法B中数据提交，遇到异常没有回滚，代码如下。

@Service
@Slf4j
public class ComeServiceImpl implements ComeService {
    @Autowired
    UserMapper userMapper;
    @Override
    public int A() {
        User user1 = new User(11,"a",111,"a");
        userMapper.saveUser(user1);
        this.B();
        return 0;
    }
    @Override
    @Transactional
    public int B() {
        User user2 = new User(11,"b",111,"b");
        userMapper.saveUser(user2);
        int i = 1 / 0;
        return 0;
    }
}

6，场景六，同一个Service内方法调用，当@Transactional 注解作用在类上时，事务起作用，数据回滚，代码如下。

@Service
@Slf4j
@Transactional
public class ComeServiceImpl implements ComeService {
    @Autowired
    UserMapper userMapper;
    @Override
    public int A() {
        User user1 = new User(11,"a",111,"a");
        userMapper.saveUser(user1);
        this.B();
        return 0;
    }
    @Override
    public int B() {
        User user2 = new User(11,"b",111,"b");
        userMapper.saveUser(user2);
        int i = 1 / 0;
        return 0;
    }
}

Java注解@Transactional事务类内调用不生效问题及解决办法pdf0星超过10%的资源63KB下载

7，场景七，同一个Service内方法调用私有的方法C，当@Transactional 注解作用在方法A上时，事务起作用，数据回滚，代码如下。

@Service
@Slf4j
public class ComeServiceImpl implements ComeService {
    @Autowired
    UserMapper userMapper;
    @Override
    @Transactional
    public int A() {
        User user1 = new User(11,"a",111,"a");
        userMapper.saveUser(user1);
        this.C();
        return 0;
    }
    private int C() {
        User user2 = new User(11,"b",111,"b");
        userMapper.saveUser(user2);
        int i = 1 / 0;
        return 0;
    }
    @Override
    public int B() {
        return 0;
    }
}

8，场景八，同一个Service内方法调用私有的方法C，当@Transactional 注解作用在方法C上时，事务不起作用，方法A中的数据提交，方法C中的数据提交，代码如下。

@Service
@Slf4j
public class ComeServiceImpl implements ComeService {
    @Autowired
    UserMapper userMapper;
    @Override
    public int A() {
        User user1 = new User(11,"a",111,"a");
        userMapper.saveUser(user1);
        this.C();
        return 0;
    }
    @Transactional
    private int C() {
        User user2 = new User(11,"b",111,"b");
        userMapper.saveUser(user2);
        int i = 1 / 0;
        return 0;
    }
    @Override
    public int B() {
        return 0;
    }
}

9，场景九，不同Service方法间调用，当@Transactional 注解作用在方法A上时，事务起作用，方法A中的数据回滚，方法saveClassInfo中的数据回滚，代码如下。

@Service
@Slf4j
public class ComeServiceImpl implements ComeService {
    @Autowired
    UserMapper userMapper;
    @Autowired
    ClassInfoService classInfoService;
    @Override
    @Transactional
    public int A() {
        User user1 = new User(11,"a",111,"a");
        userMapper.saveUser(user1);
        classInfoService.saveClassInfo();
        return 0;
    }
    @Override
    public int B() {
        return 0;
    }
}
@Service
public class ClassInfoServiceImpl implements ClassInfoService {
    @Autowired
    ClassInfoMapper classInfoMapper;
    @Override
    public int saveClassInfo() {
        ClassInfo classInfo = new ClassInfo("c","c",69D);
        classInfoMapper.saveClassInfo(classInfo);
        int i = 1/0;
        return 0;
    }
}

10，场景十，不同Service方法间调用，当@Transactional 注解作用在方法saveClassInfo上时，事务对A不起作用，方法A中的数据提交，方法saveClassInfo数据回滚，代码如下。

@Service
@Slf4j
public class ComeServiceImpl implements ComeService {
    @Autowired
    UserMapper userMapper;
    @Autowired
    ClassInfoService classInfoService;
    @Override
    public int A() {
        User user1 = new User(11,"a",111,"a");
        userMapper.saveUser(user1);
        classInfoService.saveClassInfo();
        return 0;
    }
    @Override
    public int B() {
        return 0;
    }
}
@Service
public class ClassInfoServiceImpl implements ClassInfoService {
    @Autowired
    ClassInfoMapper classInfoMapper;
    @Override
    @Transactional
    public int saveClassInfo() {
        ClassInfo classInfo = new ClassInfo("c","c",69D);
        classInfoMapper.saveClassInfo(classInfo);
        int i = 1/0;
        return 0;
    }
}