Spring AOP与IOC以及自定义注解

Spring AOP实现日志服务

pom.xml需要的jar

<dependency><groupId>org.apache.commons</groupId><artifactId>commons-lang3</artifactId><version>3.4</version>
</dependency>
<dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>4.2.4.RELEASE</version>
</dependency>
<dependency><groupId>org.springframework</groupId><artifactId>spring-core</artifactId><version>4.2.4.RELEASE</version>
</dependency>
<dependency><groupId>org.springframework</groupId><artifactId>spring-beans</artifactId><version>4.2.4.RELEASE</version>
</dependency>
<dependency><groupId>org.springframework</groupId><artifactId>spring-aop</artifactId><version>4.2.4.RELEASE</version>
</dependency>
<dependency><groupId>org.springframework</groupId><artifactId>spring-web</artifactId><version>4.2.4.RELEASE</version>
</dependency>
<dependency><groupId>cglib</groupId><artifactId>cglib-nodep</artifactId><version>3.2.0</version>
</dependency>
<dependency><groupId>org.aspectj</groupId><artifactId>aspectjweaver</artifactId><version>1.8.8</version>
</dependency>
<dependency><groupId>aopalliance</groupId><artifactId>aopalliance</artifactId><version>1.0</version>
</dependency>
<dependency><groupId>commons-collections</groupId><artifactId>commons-collections</artifactId><version>3.2.2</version>
</dependency>
<dependency><groupId>commons-logging</groupId><artifactId>commons-logging</artifactId><version>1.2</version>
</dependency>

一.AOP用法一配置XML

1.Before Advice

Before Advice会在目标方法执行之前被调用，可以通过实现org.springframework.aop.MethodBeforeAdvice接口实现。

LogBeforeAdvice.java

package com.blog.csdn.net.unix21;import java.lang.reflect.Method;
import java.util.logging.Level;
import org.springframework.aop.MethodBeforeAdvice;
import java.util.logging.Logger;/**** @author http://blog.csdn.net/unix21/*/
public class LogBeforeAdvice implements MethodBeforeAdvice {private Logger logger=Logger.getLogger(this.getClass().getName());public void before(Method method,Object[] args,Object target) throws Throwable{logger.log(Level.INFO,"日志信息>>>method starts..."+method);}
}

beans-config.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"xmlns:context="http://www.springframework.org/schema/context"xmlns:mvc="http://www.springframework.org/schema/mvc"xsi:schemaLocation="   http://www.springframework.org/schema/beans   http://www.springframework.org/schema/beans/spring-beans-4.0.xsd   http://www.springframework.org/schema/context   http://www.springframework.org/schema/context/spring-context-4.0.xsd  http://www.springframework.org/schema/mvc   http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsdhttp://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd"> 
<bean id="LogBeforeAdvice" class="blog.csdn.net.unix21.LogBeforeAdvice"/>
<bean id="HelloSpeaker" class="blog.csdn.net.unix21.HelloSpeake"/>
<bean id="HelloProxy" class="org.springframework.aop.framework.ProxyFactoryBean"><property name="proxyInterfaces" value="blog.csdn.net.unix21.IHello"/><property name="target" ref="HelloSpeaker"/><property name="interceptorNames"><list><value>LogBeforeAdvice</value></list></property>
</bean>
</beans>

接口

IHello.java

package blog.csdn.net.unix21;public interface IHello {
public void hello(String name);
}

HelloSpeaker.java

package blog.csdn.net.unix21;public class HelloSpeaker implements IHello {public void hello(String name){System.out.println("Hello, "+name);}
}

测试Before Advice

SpringAOP 前置增强 后置增强 编程式 需XML配置

  ApplicationContext context=new ClassPathXmlApplicationContext("beans-config.xml");IHello h=(IHello)context.getBean("helloProxy");h.hello("blog.csdn.net.unix21")

运行成功使用AOP的方式打印日志信息：

参考：《Spring 2.0技术手册》

Spring 3.1编写AOP时需要导入的倚赖jar包汇总

菜鸟学SSH（七）——Spring jar包详解

2.After Advice

After Advice会在目标方法执行之后被调用，可以通过实现org.springframework.aop.AfterReturningAdvice接口来实现

import java.lang.reflect.Method;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.springframework.aop.AfterReturningAdvice;public class LogAfterAdvice  implements AfterReturningAdvice  {
private Logger logger=Logger.getLogger(this.getClass().getName());public void afterReturning(Object object, Method method, Object[] args, Object target) throws Throwable {logger.log(Level.INFO,"日志信息<<<method ends..."+method);}  
}

修改beans-config.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"xmlns:context="http://www.springframework.org/schema/context"xmlns:mvc="http://www.springframework.org/schema/mvc"xsi:schemaLocation="   http://www.springframework.org/schema/beans   http://www.springframework.org/schema/beans/spring-beans-4.0.xsd   http://www.springframework.org/schema/context   http://www.springframework.org/schema/context/spring-context-4.0.xsd  http://www.springframework.org/schema/mvc   http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsdhttp://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd"> 
<bean id="LogBeforeAdvice" class="blog.csdn.net.unix21.LogBeforeAdvice"/>
<bean id="HelloSpeaker" class="blog.csdn.net.unix21.HelloSpeake"/>
<bean id="HelloProxy" class="org.springframework.aop.framework.ProxyFactoryBean"><property name="proxyInterfaces" value="blog.csdn.net.unix21.IHello"/><property name="target" ref="HelloSpeaker"/><property name="interceptorNames"><list><value>LogBeforeAdvice</value><value>LogAfterAdvice</value></list></property>
</bean>
</beans>

成功的执行了LogAfterAdvice

二.AOP用法二编程式不配置XML

SpringAOP 前置增强 后置增强 编程式 无需XML配置

ProxyFactory pf=new ProxyFactory();
pf.setTarget(new TestModel());
pf.addAdvice(new LogBeforeAdvice());
pf.addAdvice(new LogAfterAdvice());
TestModel gt=(TestModel)pf.getProxy();
return gt.add(...);

效果是一样的。

三.Java自定义注解和运行时靠反射获取注解

还是日志信息，我们希望运行的时候可以获取自定义注解

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;@Retention(RetentionPolicy.RUNTIME) // 注解会在class字节码文件中存在，在运行时可以通过反射获取到  
@Target({ElementType.FIELD,ElementType.METHOD})//定义注解的作用目标**作用范围字段、枚举的常量/方法  
@Documented//说明该注解将被包含在javadoc中 
public @interface FieldMeta {/** * 是否为序列号 * @return */  boolean id() default false;  /** * 字段名称 * @return */  String name() default "";  /** * 是否可编辑 * @return */  boolean editable() default true;  /** * 是否在列表中显示 * @return */  boolean summary() default true;  /** * 字段描述 * @return */  String description() default "";  /** * 排序字段 * @return */  int order() default 0;  
}

声明注解

需要注意如果一个类是接口的实现，那么这种注解需要写接口方法上，例如AOP的调用方式一，对于AOP的调用方式二可以把注解写类的方法上即可。

调用

if (method.isAnnotationPresent(FieldMeta.class)) {FieldMeta myAnnotation = method.getAnnotation(FieldMeta.class);System.out.println("注解：" + myAnnotation.description() + " 类："+target.getClass().getName()+" 方法：" + method.getName());
}

参考：Java自定义注解和运行时靠反射获取注解