@Transactional 失效

在项目中，@Transactional(rollbackFor=Exception.class)，如果类加了这个注解，那么这个类里面的方法抛出异常，就会回滚，数据库里面的数据也会回滚。
在@Transactional注解中如果不配置rollbackFor属性,那么事物只会在遇到RuntimeException的时候才会回滚,加上rollbackFor=Exception.class,可以让事物在遇到非运行时异常时也回滚

@Transactional(rollbackFor = Exception.class)
    public void addHazardMater1(HazardMaterQO qo) {
        HazardMater hazardMater = BeanCopyUtil.copyBeanClass(qo, HazardMater.class);
            try{
                hazardMaterMapper.insertSelective(hazardMater);
            }catch (Exception e){
                throw new BusinessException(RequestCodeEnum.MATER_IS_EXIST);
            }
    }

用try-catch 捕捉异之后可以throw一个新的异常，如，throw new RuntimeException(“事务回滚”);
但是这种情况下前端报错，很不友好，所以最好自己定义一个异常类

public class BusinessException extends RuntimeException {

    
    private String code;

    
    private String msg;

    public BusinessException(RequestCodeEnum requestCodeEnum) {
        this.code = requestCodeEnum.getCode();
        this.msg = requestCodeEnum.getMsg();
    }

    public BusinessException(String code,String msg) {
        this.code = code;
        this.msg = msg;
    }

    public BusinessException(String msg) {
        this.msg = msg;
    }

    public String getResponseCode() {
        return code;
    }

    public void setResponseCode(String responseCode) {
        this.code = responseCode;
    }

    @Override
    public String getMessage() {
        return msg;
    }

    public void setMessage(String message) {
        this.msg = message;
    }
}

其中的RequestCodeEnum 是个枚举类，用来存放错误数据的编码

public enum RequestCodeEnum {

    OK("00","成功"),
    ERROR("20","服务器错误"),
    PARAM_ERROR("30","请求参数错误"),

    MATER_IS_EXIST("40", "该数据已重复")
    ;


    private String code;

    private String msg;

    private RequestCodeEnum(String code, String msg) {
        this.code = code;
        this.msg = msg;
    }


    public String getCode() {
        return code;
    }

    public String getMsg() {
        return msg;
    }
}

或者设置手动回滚 TransactionAspectSupport.currentTransactionStatus().setRollbackonly();

@Transactional(rollbackFor = Exception.class)
    public void addHazardMater1(HazardMaterQO qo) {
        HazardMater hazardMater = BeanCopyUtil.copyBeanClass(qo, HazardMater.class);
            try{
                hazardMaterMapper.insertSelective(hazardMater);
            }catch (Exception e){
                TransactionAspectSupport.currentTransactionStatus().setRollbackonly();
            }
    }

这里以 MySQL 为例，其 MyISAM 引擎是不支持事务操作的，InnoDB 才是支持事务的引擎，一般要支持事务都会使用 InnoDB。

以下来自 Spring 官方文档：

When using proxies, you should apply the @Transactional annotation only to methods with public visibility. If you do annotate protected, private or package-visible methods with the @Transactional annotation, no error is raised, but the annotated method does not exhibit the configured transactional settings. Consider the use of AspectJ (see below) if you need to annotate non-public methods.

在类内部没有添加@Transactional的方法，调用了@Transactional方法时，当你调用时，他也不会回滚

@Service

public class Testservice{

    public void add(QO qo) {

        addQo(qo);
    }

    @Transactional

    public void addQo(QO qo) {

        // add  Qo
    }

}

失败的原理：@Transactional是基于动态代理对象来实现的，而在类内部的方法的调用是通过this关键字来实现的，没有经过动态代理对象，所以事务回滚失效。

//@Service
public class Testservice{
    @Transactional
    public void addQo(QO qo) {
        // add  Qo
    }
}