spring(3)：spring的AOP
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下面看具体的例子：
定义Person接口，声明两个方法
package lee;public interface Person {void info();void run();}?
具体的实现类
package lee;public class PersonImpl implements Person {private String name;private int age;public void info() {System.out.println("我的名字是："+name+"，今年年龄为:"+age);}public void run() {if(age > 45){System.out.println("我年老体弱，只能慢跑");}else{System.out.println("我年轻体壮，可以快跑");}}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}}?
下面定义三个拦截器
package lee;import java.lang.reflect.Method;import org.springframework.aop.MethodBeforeAdvice;public class MyBeforeAdvisor implements MethodBeforeAdvice {public void before(Method m, Object[] arg, Object target)throws Throwable {System.out.println("方法调用前...");System.out.println("下面是方法调用的信息...");System.out.println("所执行的方法是..."+m);System.out.println("调用方法的参数是..."+arg);System.out.println("目标对象是..."+target);}}?
package lee;import org.aopalliance.intercept.MethodInterceptor;import org.aopalliance.intercept.MethodInvocation;public class MyAroundInterceptor implements MethodInterceptor {public Object invoke(MethodInvocation invocation) throws Throwable {System.out.println("调用方法之前：invocation对象：["+invocation+"]");Object rval = invocation.proceed();System.out.println("调用结束...");return rval;}}?
package lee;import java.lang.reflect.Method;import org.springframework.aop.AfterReturningAdvice;public class MyAfterAdvisor implements AfterReturningAdvice {public void afterReturning(Object returnValue, Method m, Object[] args,Object target) throws Throwable {System.out.println("方法调用结束...");System.out.println("目标方法的返回值是:..."+returnValue);System.out.println("目标方法是..."+m);System.out.println("目标方法的参数是..."+args);System.out.println("目标对象是..."+target);}}?
spring配置文件
<bean id="personTarget" name="code">package lee;import org.springframework.beans.factory.xml.XmlBeanFactory;import org.springframework.core.io.ClassPathResource;public class BeanTest {public static void main(String[] args) {XmlBeanFactory factory = new XmlBeanFactory(new ClassPathResource("applicationContext.xml"));Person p = (Person)factory.getBean("person");p.run();}}?最后打印出
方法调用前...下面是方法调用的信息...所执行的方法是...public abstract void lee.Person.run()调用方法的参数是...[Ljava.lang.Object;@184ec44目标对象是...lee.PersonImpl@1b383e9调用方法之前：invocation对象：[ReflectiveMethodInvocation: public abstract void lee.Person.run(); target is of class [lee.PersonImpl]]我年老体弱，只能慢跑调用结束...方法调用结束...目标方法的返回值是:...null目标方法是...public abstract void lee.Person.run()目标方法的参数是...[Ljava.lang.Object;@99681b目标对象是...lee.PersonImpl@1b383e9
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下面再看一个权限校验的例子：
package permission;public interface TestService {void view();void modify();}?
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package permission;public class TestServiceImpl implements TestService {public void modify() {System.out.println("用户修改数据");}public void view() {System.out.println("用户查看数据");}}?
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package permission;public interface TestAction {public void view();public void modify();}?
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package permission;public class TestActionImpl implements TestAction {private TestService ts;public void modify() {ts.modify();}public void view() {ts.view();}public void setTs(TestService ts) {this.ts = ts;}}?
拦截类，这个类中会进行验权
package permission;import org.aopalliance.intercept.MethodInterceptor;import org.aopalliance.intercept.MethodInvocation;public class AuthorityInterceptor implements MethodInterceptor {private String user;public void setUser(String user) {this.user = user;}public Object invoke(MethodInvocation invocation) throws Throwable {System.out.println("-------------------------");String methodName = invocation.getMethod().getName();if(!user.equals("admin") && !user.equals("registedUser")){System.out.println("你无权执行该方法");return null;}else if(user.equals("registedUser") && methodName.equals("modify")){System.out.println("你不是管理员，无法修改数据");return null;}else {return invocation.proceed();}}}?
spring中的配置文件
<bean id="serviceTarget" name="code">package permission;import org.springframework.beans.factory.xml.XmlBeanFactory;import org.springframework.core.io.ClassPathResource;public class BeanTest {public static void main(String[] args) {XmlBeanFactory factory = new XmlBeanFactory(new ClassPathResource("applicationContext.xml"));TestAction ta = (TestAction)factory.getBean("testAction");ta.modify();ta.view();}}?结果打印：
-------------------------你不是管理员，无法修改数据-------------------------用户查看数据
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这个例子属于功能增强的概念，将验权功能植入action类中。
如果没有接口，只有具体类应该怎么做？如只有TestServiceImpl类，没有TestService接口，那么应该如何拦截，
可在spring配置文件中将设置一个属性proxyTargetClass，将其值设为true，表示目标类是个具体类，如下粗体所示。
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<bean id="service" class="org.springframework.aop.framework.ProxyFactoryBean"> <property name="proxyTargetClass"> <value>true</value> </property><property name="target"><ref local="serviceTarget"/></property><property name="interceptorNames"><list><value>authorityInterceptor</value></list></property></bean>
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