spring boot:方法中使用try...catch导致@Transactional事务无效的解决(spring boot 2.3.4)

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一，方法中使用try...catch导致@Transactional事务无效的解决方法

1,问题的描述:

如果一个方法添加了@Transactional注解声明事务，

而方法内又使用了try catch 捕捉异常，

则方法内的异常捕捉会覆盖事务对异常的判断，

从而异致事务失效而不回滚

2, 如何解决？

第一个方法：给@Transactional注解增加:rollbackFor后并手动抛出指定的异常

第二个方法：在捕捉到异常后手动rollback

说明：刘宏缔的架构森林是一个专注架构的博客，地址：https://www.cnblogs.com/architectforest

对应的源码可以访问这里获取： https://github.com/liuhongdi/

说明：作者:刘宏缔邮箱: 371125307@qq.com

二，演示项目的相关信息

1,项目地址:

https://github.com/liuhongdi/transactional

2,功能说明：

演示了事务方法中捕捉异常时如何使事务回滚

3,项目结构：如图:

三，配置文件说明

1,pom.xml

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency> 
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency> 
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>

2,application.properties

#mysql
spring.datasource.url=jdbc:mysql://localhost:3306/store?characterEncoding=utf8&useSSL=false
spring.datasource.username=root
spring.datasource.password=password
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver#mybatis
mybatis.mapper-locations=classpath:/mapper/*Mapper.xml
mybatis.type-aliases-package=com.example.demo.mapper

3,创建数据表goods的sql

CREATE TABLE `goods` (
`goodsId` bigint(11) unsigned NOT NULL AUTO_INCREMENT COMMENT 'id',
`goodsName` varchar(500) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL DEFAULT '' COMMENT 'name',
`subject` varchar(200) NOT NULL DEFAULT '' COMMENT '标题',
`price` decimal(15,2) NOT NULL DEFAULT '0.00' COMMENT '价格',
`stock` int(11) NOT NULL DEFAULT '0' COMMENT 'stock',
PRIMARY KEY (`goodsId`),
UNIQUE KEY `goodsName` (`goodsName`)
) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci COMMENT='商品表'

注意goodsName字段上有一个唯一的索引，
后面我们会利用它来引发一个duplicate entry 异常

插入一条数据:

INSERT INTO `goods` (`goodsId`, `goodsName`, `subject`, `price`, `stock`) VALUES
(3, '100分电动牙刷', '好用到让你爱上刷牙', '59.00', 100);

四，java代码说明

1,LockController.java

@RestController
@RequestMapping("/lock")
public class LockController { @Resource
OrderService orderService; //购买商品,方法内没有捕捉异常
@GetMapping("/lock")
@ResponseBody
public String buyLock() {
try {
int goodsId = 3;
orderService.decrementProductStoreLock(goodsId,1);
return "success";
} catch (Exception e){
System.out.println("捕捉到了异常 in controller");
e.printStackTrace();
String errMsg = e.getMessage();
return errMsg;
}
} //购买商品，方法内捕捉异常
@GetMapping("/lockcatch")
@ResponseBody
public String buyLockCatch() {
try {
int goodsId = 3;
boolean isDecre = orderService.decrementProductStoreLockWithCatch(goodsId,1);
if (isDecre) {
return "success";
} else {
return "false";
}
} catch (Exception e){
System.out.println("捕捉到了异常 in controller");
e.printStackTrace();
String errMsg = e.getMessage();
return errMsg;
}
} //购买商品，方法内捕捉异常
@GetMapping("/lockcatch1")
@ResponseBody
public String buyLockCatch1() {
try {
int goodsId = 3;
boolean isDecre = orderService.decrementProductStoreLockWithCatch1(goodsId,1);
if (isDecre) {
return "success";
} else {
return "false";
}
} catch (Exception e){
System.out.println("捕捉到了异常 in controller");
e.printStackTrace();
String errMsg = e.getMessage();
return errMsg;
}
} //购买商品，方法内捕捉异常
@GetMapping("/lockcatch2")
@ResponseBody
public String buyLockCatch2() {
try {
int goodsId = 3;
boolean isDecre = orderService.decrementProductStoreLockWithCatch2(goodsId,1);
if (isDecre) {
return "success";
} else {
return "false";
}
} catch (Exception e){
System.out.println("捕捉到了异常 in controller");
e.printStackTrace();
String errMsg = e.getMessage();
return errMsg;
}
}}

2，GoodsMapper.java

@Repository
@Mapper
public interface GoodsMapper {
Goods selectOneGoods(int goods_id);
int updateOneGoodsStock(Goods goodsOne);
int insertOneGoods(Goods goodsOne);
}

3,Goods.java

public class Goods {
//商品id
private int goodsId;
public int getGoodsId() {
return this.goodsId;
}
public void setGoodsId(int goodsId) {
this.goodsId = goodsId;
} //商品名字
private String goodsName;
public String getGoodsName() {
return this.goodsName;
}
public void setGoodsName(String goodsName) {
this.goodsName = goodsName;
} //商品库存数
private int stock;
public int getStock() {
return this.stock;
}
public void setStock(int stock) {
this.stock = stock;
}
}

4,OrderService.java

public interface OrderService {
public boolean decrementProductStoreLock(int goodsId, int buyNum);
public boolean decrementProductStoreLockWithCatch(int goodsId, int buyNum);
public boolean decrementProductStoreLockWithCatch1(int goodsId, int buyNum);
public boolean decrementProductStoreLockWithCatch2(int goodsId, int buyNum);
}

5,OrderServiceImpl.java

@Service
public class OrderServiceImpl implements OrderService { @Resource
private GoodsMapper goodsMapper; /*
*
* 减库存，供其他方法调用
* */
private boolean decrestock(int goodsId, int buyNum) {
Goods goodsOne = goodsMapper.selectOneGoods(goodsId);
System.out.println("-------------------------当前库存:"+goodsOne.getStock()+"-------购买数量:"+buyNum);
if (goodsOne.getStock() < buyNum || goodsOne.getStock() <= 0) {
System.out.println("------------------------fail:buy fail,return");
return false;
}
int upStock = goodsOne.getStock()-buyNum;
goodsOne.setStock(upStock);
int upNum = goodsMapper.updateOneGoodsStock(goodsOne);
System.out.println("-------------------------success:成交订单数量:"+upNum); int insNum = goodsMapper.insertOneGoods(goodsOne);
System.out.println("-------------------------success:ins数量:"+insNum); return true;
} //方法内不做try catch捕捉异常，可以正常回滚
@Override
@Transactional(isolation = Isolation.REPEATABLE_READ)
public boolean decrementProductStoreLock(int goodsId, int buyNum) {
return decrestock(goodsId, buyNum);
} //异常时不处理，会导致不回滚
@Override
@Transactional(rollbackFor={Exception.class})
public boolean decrementProductStoreLockWithCatch(int goodsId, int buyNum) {
try {
return decrestock(goodsId, buyNum);
} catch (Exception e) {
System.out.println("捕捉到了异常in service method");
e.printStackTrace();
String errMsg = e.getMessage();
//throw e;
return false;
}
} //异常时手动抛出异常
@Override
@Transactional(rollbackFor={Exception.class})
public boolean decrementProductStoreLockWithCatch1(int goodsId, int buyNum) {
try {
return decrestock(goodsId, buyNum);
} catch (Exception e) {
System.out.println("捕捉到了异常in service method");
e.printStackTrace();
String errMsg = e.getMessage();
throw e;
}
} //异常时手动rollback
@Override
@Transactional(isolation = Isolation.REPEATABLE_READ)
public boolean decrementProductStoreLockWithCatch2(int goodsId, int buyNum) {
try {
return decrestock(goodsId, buyNum);
} catch (Exception e) {
System.out.println("捕捉到了异常in service method");
e.printStackTrace();
String errMsg = e.getMessage();
//手动rollback
TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();
return false;
}
}
}

说明：decrestock这个方法中有两个写操作，分别是：减库存和insert一条商品记录，

后者会引发duplicate entry异常

6,GoodsMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.transactional.demo.mapper.GoodsMapper">
<select id="selectOneGoods" parameterType="int" resultType="com.transactional.demo.pojo.Goods">
select * from goods where goodsId=#{goodsId}
</select> <update id="updateOneGoodsStock" parameterType="com.transactional.demo.pojo.Goods">
UPDATE goods SET
stock = #{stock}
WHERE goodsId = #{goodsId}
</update> <insert id="insertOneGoods" parameterType="com.transactional.demo.pojo.Goods" useGeneratedKeys="true" keyProperty="goodsId">
insert into goods(goodsName) values( #{goodsName})
</insert>
</mapper>

五，测试效果

1,测试正常回滚：访问:

http://127.0.0.1:8080/lock/lock

### Error updating database. Cause: java.sql.SQLIntegrityConstraintViolationException: Duplicate entry '100分电动牙刷' for key 'goodsName'
### The error may involve com.transactional.demo.mapper.GoodsMapper.insertOneGoods-Inline
### The error occurred while setting parameters
### SQL: insert into goods(goodsName) values( ?)
### Cause: java.sql.SQLIntegrityConstraintViolationException: Duplicate entry '100分电动牙刷' for key 'goodsName' ;
Duplicate entry '100分电动牙刷' for key 'goodsName';
nested exception is java.sql.SQLIntegrityConstraintViolationException: Duplicate entry '100分电动牙刷' for key 'goodsName'

查看数据表：

库存未减少，说明正常回滚

查看控制台:

-------------------------当前库存:100-------购买数量:1
-------------------------success:成交订单数量:1
捕捉到了异常 in controller

2,测试事务无效，不能正常回滚:访问:

http://127.0.0.1:8080/lock/lockcatch

false

查看数据表:

回滚失效

查看控制台:

-------------------------当前库存:100-------购买数量:1
-------------------------success:成交订单数量:1
捕捉到了异常in service method

3,测试捕捉到异常后手动抛出异常引发回滚:

访问:

http://127.0.0.1:8080/lock/lockcatch1

查看数据表:

查看控制台:

-------------------------当前库存:99-------购买数量:1
-------------------------success:成交订单数量:1
捕捉到了异常in service method
...
捕捉到了异常 in controller
...

4,测试捕捉到异常后手动回滚

访问:

http://127.0.0.1:8080/lock/lockcatch2

false

查看数据表:

查看控制台:

-------------------------当前库存:99-------购买数量:1
-------------------------success:成交订单数量:1
捕捉到了异常in service method

5,大家注意最后两个返回的区别：为什么会不一样？

手动抛出异常后，会被controller捕捉到，所以没有返回success或false,

而是返回了异常的提示信息

六，查看spring boot的版本:

. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.3.4.RELEASE)