[SpringBoot] Nine, use AOP aspect to open global transaction management in SpringBoot

In the development process of JavaEE, the service method is used to process the main business logic, and the processing of the business logic is often accompanied by multiple operations on the database. We cannot guarantee that the business logic can be executed completely correctly. Join transaction management, once the program goes wrong, the database can be rolled back to ensure the accuracy of the data

1. Create TransactionConfig.java file

import org.aspectj.lang.annotation.Aspect;
import org.springframework.aop.Advisor;
import org.springframework.aop.aspectj.AspectJExpressionPointcut;
import org.springframework.aop.support.DefaultPointcutAdvisor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.interceptor.DefaultTransactionAttribute;
import org.springframework.transaction.interceptor.NameMatchTransactionAttributeSource;
import org.springframework.transaction.interceptor.TransactionInterceptor;

/**
 * @ClassName TransactionConfig
 * 事务管理配置，拦截service包下所有方法
 * @Author Lizhou
 * @Date 2019-09-05 17:39:39
 * @Version 1.0
 **/
@Aspect
@Configuration
public class TransactionConfig {

    /**
     * 切面地址
     */
    private static final String AOP_POINTCUT_EXPRESSION = "execution(* com.lzzy.meet.service.*.*(..))";
    /**
     * 事务失效时间
     */
    private static final int TX_METHOD_TIMEOUT = 5;

    @Autowired
    private PlatformTransactionManager transactionManager;

    /**
     * 事务配置
     *
     * @return
     */
    @Bean
    public TransactionInterceptor txAdvice() {

        DefaultTransactionAttribute txAttr_REQUIRED = new DefaultTransactionAttribute();
        /**
         * PROPAGATION_REQUIRED:事务隔离性为 1
         * 若当前存在事务，则加入该事务
         * 如果当前没有事务，则创建一个新的事务，这是默认值
         */
        txAttr_REQUIRED.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
        /**
         * 设置事务失效时间，如果超过5秒，则回滚事务
         */
        txAttr_REQUIRED.setTimeout(TX_METHOD_TIMEOUT);

        DefaultTransactionAttribute txAttr_REQUIRED_READONLY = new DefaultTransactionAttribute();
        /**
         * transactiondefinition 定义事务的隔离级别；
         * PROPAGATION_NOT_SUPPORTED 事务传播级别5，以非事务运行，如果当前存在事务，则把当前事务挂起
         */
        txAttr_REQUIRED_READONLY.setPropagationBehavior(TransactionDefinition.PROPAGATION_NOT_SUPPORTED);
        /**
         * 设置当前事务是否为只读事务
         * true为只读
         */
        txAttr_REQUIRED_READONLY.setReadOnly(true);

        /**
         * 事务管理规则，声明具备事务管理的方法名
         */
        NameMatchTransactionAttributeSource source = new NameMatchTransactionAttributeSource();

        source.addTransactionalMethod("save*", txAttr_REQUIRED);
        source.addTransactionalMethod("add*", txAttr_REQUIRED);
        source.addTransactionalMethod("delete*", txAttr_REQUIRED);
        source.addTransactionalMethod("update*", txAttr_REQUIRED);

        source.addTransactionalMethod("get*", txAttr_REQUIRED_READONLY);
        source.addTransactionalMethod("query*", txAttr_REQUIRED_READONLY);
        source.addTransactionalMethod("find*", txAttr_REQUIRED_READONLY);
        source.addTransactionalMethod("list*", txAttr_REQUIRED_READONLY);
        source.addTransactionalMethod("count*", txAttr_REQUIRED_READONLY);

        return new TransactionInterceptor(transactionManager, source);
    }

    /**
     * 利用AspectJExpressionPointcut设置切面=切点+通知（写成内部bean的方式）
     *
     * @return
     */
    @Bean
    public Advisor txAdviceAdvisor() {
        /**
         * 声明切点的面
         * 切面（Aspect）：切面就是通知和切入点的结合。
         * 通知和切入点共同定义了关于切面的全部内容——它的功能、在何时和何地完成其功能
         */
        AspectJExpressionPointcut pointcut = new AspectJExpressionPointcut();
        /**
         * 声明和设置需要拦截的方法,用切点语言描写
         */
        pointcut.setExpression(AOP_POINTCUT_EXPRESSION);
        /**
         * 设置切面=切点pointcut+通知TxAdvice
         */
        return new DefaultPointcutAdvisor(pointcut, txAdvice());
    }
}

2. Analysis

Define a aspect through @Aspect , use @Configuration to declare that the current class is a configuration class

Our business logic is generally placed in the service layer for processing, so our entry point is defined as: com.lzzy.meet.service .. (…) , That is, all methods under service

We set the transaction failure time to: 5 seconds, more than five seconds, then roll back the transaction, and define the isolation and isolation level of the transaction, and declare the transaction as read-only

Finally, we use AspectJExpressionPointcut to set the aspect = the point of cut + notification (written as an internal bean)

SpringBoot uses AOP aspect to open global transaction management

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