Spring中的事宜管理器（Aspectj）

Spring 的AOP确实强大！

但是AOP在实际的工作运用中，无外乎就是权限的验证（当然动态代理模式也可以轻松实现）！日志的处理!

但用的最多的还是事务的管理！

而在Spring中的事务管理又分为：A、编程式事物处理

?????????????????????????????????????????????? 优点：可以精确的控制事物的边界

?????????????????????????????????????????????? 缺点是：实现不是很优雅！因为在每一个需事务管理的业务逻辑中都需要调用

TransactionTemplate? 的execute（）方 法，导致了业务逻辑和系统业务的交叉！

????????????????????????????????????????????? B、声明式事物：采用了AOP优雅的解决了编程式事物的缺点


（在中小型项目中用A比较好，事物处理比较单一；大型项目，事物处理比较多的话，用B比较好）



而我们其实在工作中利用注解的方式还要简单些！所以我利用Aspectj加AOP也解决了编程式事物处理的缺点！

以下是我的测试案例


步骤： 1、配置Spring 的Datasource ,TransactionManager,TransactionTemplate

?????????? 2、定义标注@interface?

?????????? 3、定义Aspect（@Aspect，@around），定义切入点

?????????? 4、在Spring中配置Aspect就是配置一个简单ben





****************************************************************



package com.lovo.annotation;

public class AService {
? public void createBook(){
?? System.out.println("@@@@@@@@@@@");
? }
? public static void main(String[] args) {
AService a = (AService)SpringUtil.getContext().getBean("a");
a.createBook();
}
}




*****************************************************************************


package com.lovo.annotation;

import javax.sql.DataSource;

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.TransactionCallback;
import org.springframework.transaction.support.TransactionTemplate;
/**
* 增加书的业务操作方法
* @author Administrator
*
*/
public class BookService {
//事物模板
private TransactionTemplate trans;
//数据源
private DataSource dataSource;

public TransactionTemplate getTrans() {
? return trans;
}

public void setTrans(TransactionTemplate trans) {
? this.trans = trans;
}

public DataSource getDataSource() {
? return dataSource;
}

public void setDataSource(DataSource dataSource) {
? this.dataSource = dataSource;
}
//添加事物属性值
@Trans(TransactionTemplate.PROPAGATION_REQUIRED)

/**
? * 业务方法
? */
??? public void createBook(){
? //创建jdbc模板
???? JdbcTemplate jdbc = new JdbcTemplate(dataSource);
???? //执行插入数据库操作
???? jdbc.update("insert into T_BOOK values(5522,'Spring3 in Action',3)");
????
??? }
}




*******************************************************************************


package com.lovo.annotation;
/**
* 测试类
* @author Administrator
*
*/
public class Client {
? public static void main(String[] args) {
BookService bookServ = (BookService)SpringUtil.getContext().getBean("bookService");
bookServ.createBook();
? }
}
*************************************************************************

package com.lovo.annotation;


/**
* 定义一个注释类
*/
import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.ElementType;

@Target({ElementType.METHOD})
@Retention(RUNTIME)
public @interface Trans {
int value();
}

**********************************************************************

package com.lovo.annotation;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
* 定义一个加载配置文件的单例工具类。
*
* @author Administrator
*
*/
public class SpringUtil {

private SpringUtil(){
?
}
? private static ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

? public static ApplicationContext getContext(){
?? return context;
? }
}

**************************************************************

package com.lovo.annotation;

import java.lang.reflect.Method;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.TransactionCallback;
import org.springframework.transaction.support.TransactionTemplate;

@Aspect
public class TransactionAspect {
?? // 拦截对目标对象方法调用?
@Around("execution(@com.lovo.annotation.Trans * *.*(..))")

public Object inTransaction(final ProceedingJoinPoint pjp) {
? //获得事物模板
??????? TransactionTemplate trans = (TransactionTemplate)SpringUtil.getContext().getBean("transactionTemplate");
??????? // 获取连接点的方法签名对象
??????? MethodSignature sig = (MethodSignature) pjp.getSignature();
??????? // 连接点对象的方法??
? Method method = sig.getMethod();
??????? // 返回@trans的注释对象?
? Trans antrans = (Trans) method.getAnnotation(Trans.class);
? //设定事物的属性值
? trans.setPropagationBehavior(antrans.value());
?
? //执行事务的方法
??????? return trans.execute(new TransactionCallback(){
?? public Object doInTransaction(TransactionStatus ts) {
??? Object result = null;
??? try {
???? result=pjp.proceed();
??? } catch (Throwable e) {
???? ts.setRollbackOnly();
???? e.printStackTrace();
??? }
??? return result;
?? }
????????
??????? });
?

}
}


***************************************************************************

配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"??????
??????????? xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
??????????? xmlns:aop="http://www.springframework.org/schema/aop"
?????????????? xsi:schemaLocation=???????
?????????????????? "http://www.springframework.org/schema/beans????????
?????????????????? http://www.springframework.org/schema/beans/spring-beans.xsd????????
?????????????????? http://www.springframework.org/schema/aop????????
?????????????????? http://www.springframework.org/schema/aop/spring-aop.xsd">
?<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
?<bean id="transactionTemplate" class="org.springframework.transaction.support.TransactionTemplate">
?? <property name="transactionManager">
??? <ref bean="transactionManager"/>
?? </property>
?</bean>
?<bean id="transactionManager"
?????? class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
?????? <property name="dataSource">
???????? <ref local="dataSource"/>
?????? </property>
?????? </bean>
?<bean id="dataSource"
?????? class="org.springframework.jdbc.datasource.DriverManagerDataSource">
?????? <property name="driverClassName">
???????? <value>oracle.jdbc.driver.OracleDriver</value>
?????? </property>
?????? <property name="url">
???????? <value>jdbc:oracle:thin:@localhost:1521:ORCL</value>
?????? </property>
?????? <property name="username"><value>scott</value></property>
?????? <property name="password"><value>wl</value></property>
?</bean>
?<bean id="bookService" class="com.lovo.annotation.BookService">
?? <property name="dataSource">
???? <ref bean="dataSource"/>
?? </property>
?? <property name="trans">
???? <ref bean="transactionTemplate"/>
?? </property>
?? </bean>
?? <bean id="transAspect" class="com.lovo.annotation.TransactionAspect"></bean>
?</beans>