基于springboot手写spring事务框架

项目所需依赖：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.transaction</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- SpringBoot整合Web组件 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <!-- springboot 整合mybatis框架 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>
        <!-- alibaba的druid数据库连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.9</version>
        </dependency>
        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!--aop-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

2.自定义注解：

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExtTransaction {
}

//////////////////////////////////////////
//定义切点
import com.transaction.annotation.ExtTransaction;
import com.transaction.utils.TransactionUtils;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.interceptor.TransactionAspectSupport;


// 定义切面可以让事务注解可以生效
@Aspect
@Component
public class AopExtTransaction {
    @Autowired
    private TransactionUtils transactionUtils;

    @Pointcut("execution(public * com.transaction.service.*.*(..))")
    public void rlAop() {
    }

    // 使用异常通知 接受回滚事务
    @AfterThrowing("rlAop()")
    public void afterThrowing(JoinPoint point) {
        // 获取当前事务状态
        TransactionStatus transaction = transactionUtils.gteTransactionStatus();
        if (transaction != null)
          //  transactionUtils.rollback(transaction);
            //获取当前线程的事务进行回滚
        TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();
    }

    // 事务底层原理 采用那些通知？环绕和异常即可 注意单例线程安全问题
    // 可以使用环绕通知对方法进行开启事务和提交事务 异常通知当程序抛出异常的情况下，进行回滚
    @Around("rlAop()")
    public Object around(ProceedingJoinPoint pjp) throws Throwable {
        // 1.判断方法上面是否有加上事务注解
        MethodSignature methodSignature = (MethodSignature) pjp.getSignature();
        ExtTransaction extTransaction = methodSignature.getMethod().getDeclaredAnnotation(ExtTransaction.class);
        if (extTransaction == null) {// 方法上面没有加上注解执行原有方法
            return pjp.proceed();
        }
        // 2.如果方法上加上事务直接的 开启或者是提交事务 proceed();执行原有方法
        TransactionStatus transactionStatus = transactionUtils.begin();
        Object proceed = pjp.proceed();// 执行原有方法
        transactionUtils.commit(transactionStatus);
        return proceed;
    }
}

3.dao层和业务层

@Insert("INSERT INTO `rbac_db`.`user` (`name`, `age`) VALUES (#{name}, #{age}) ")
    Integer addUser(User user);


////////////////////////////////////////////
@Service
public class UserServiceImpl {
    @Autowired
    UserMapper userMapper;
    @Autowired
    TransactionUtils transactionUtils;


    @ExtTransaction
    public Integer addUser(User user) {
        System.out.println("开始事务");
        // transactionUtils.begin();
        System.out.println("开始添加数据到数据库");
        Integer integer  = userMapper.addUser(user);
        int i = integer / 0;
        System.out.println("-----------"+integer+"----------");
        return i;
    }

经测试，在加了@ExtTransaction注解的方法发生异常后会自动回滚。