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1 从http://www.springframework.org下载spring 2 用eclipse新建java项目 3 建立我们的业务方法接口 public interface businessobject { public void dosomething(); public void doanotherthing(); } import org.apache.commons.logging.log; import org.apache.commons.logging.logfactory;public interface businessobject { public void dosomething(); public void doanotherthing(); } import org.apache.commons.logging.log; import org.apache.commons.logging.logfactory;
4 实现业务方法,注意这是的setwords使用了依赖注入,所谓依赖注入就是把配置文件中的字符串什么的在程序运行时“自动”放到我们的程序中来。如果不是这样,我们就只能在代码中固化这些东西,从而违背了面向对象的依赖倒置原则,还有一种满足依赖倒置的方法,即依赖查询,这就是所谓的factory模式,即在代码中请求某种抽象的东西,然后根据配置得到它,但这种办法向对于依赖注入多了对环境的依赖,且代码冗余,ejb的jndi查询就属于这种。另外我们的spring配置文件是以bean为核心的,就是我们写的一个类,在xml中描述它的名称、位置和涵盖的内容、关系。 public class businessobjectimpl implements businessobject { private string words; public void setwords(string words){ this.words = words; } public void dosomething() { log log = logfactory.getlog(this.getclass()); log.info(words); } public void doanotherthing() { log log = logfactory.getlog(this.getclass()); log.info("another thing"); }
}public class businessobjectimpl implements businessobject { private string words; public void setwords(string words){ this.words = words; } public void dosomething() { log log = logfactory.getlog(this.getclass()); log.info(words); } public void doanotherthing() { log log = logfactory.getlog(this.getclass()); log.info("another thing"); }
}
5 建立一个运行方法类,从配置文件spring-beans.xml中读入bo这个类的定义,然后实例化一个对象 import org.springframework.beans.factory.xml.xmlbeanfactory; import org.springframework.core.io.classpathresource;
public class main { public static void main(string[] args){ xmlbeanfactory xbf = new xmlbeanfactory(new classpathresource("spring-beans.xml")); businessobject bo = (businessobject)xbf.getbean("bo"); bo.dosomething(); bo.doanotherthing(); } }import org.springframework.beans.factory.xml.xmlbeanfactory; import org.springframework.core.io.classpathresource;
public class main { public static void main(string[] args){ xmlbeanfactory xbf = new xmlbeanfactory(new classpathresource("spring-beans.xml")); businessobject bo = (businessobject)xbf.getbean("bo"); bo.dosomething(); bo.doanotherthing(); } }
6 建立一个拦截器类invoke是methodinterceptor必须实现的方法,表示拦截时的动作,大家仔细体会代码中的含义 import org.aopalliance.intercept.methodinterceptor; import org.aopalliance.intercept.methodinvocation; import org.apache.commons.logging.log; import org.apache.commons.logging.logfactory;
public class myinterceptor implements methodinterceptor { private string before, after; public void setafter(string after) { this.after = after; } public void setbefore(string before) { this.before = before; } public object invoke(methodinvocation invocation) throws throwable { log log = logfactory.getlog(this.getclass()); log.info(before); object rval = invocation.proceed(); log.info(after); return rval; } }import org.aopalliance.intercept.methodinterceptor; import org.aopalliance.intercept.methodinvocation; import org.apache.commons.logging.log; import org.apache.commons.logging.logfactory;
public class myinterceptor implements methodinterceptor { private string before, after; public void setafter(string after) { this.after = after; } public void setbefore(string before) { this.before = before; } public object invoke(methodinvocation invocation) throws throwable { log log = logfactory.getlog(this.getclass()); log.info(before); object rval = invocation.proceed(); log.info(after); return rval; } }
7 建立配置文件组织上面的类之间的关系,aop有切入点和增强这两个重要的概念,把两个概念结合到一起,就是一个在某个方法执行的时候附加执行,切入点表示在哪里附加,增强表示附加什么,配置文件中的mypointcut表示切入点,myinterceptor表示增强的内容,myadvisor表示增强器,即两者的结合,在bo这个bean中,我们把这个增强器附加到了bo这个bean上。
<?xml version="1.0" encoding="utf-8"?> <!doctype beans public "-//spring//dtd bean//en" "http://www.springframework.org/dtd/spring-beans.dtd"> <beans> <bean id="businessobjectimpl" class="businessobjectimpl"> <property name="words"> <value>正在执行业务方法</value> </property> </bean> <bean id="myinterceptor" class="myinterceptor"> <property name="before"> <value>执行业务方法前</value> </property> <property name="after"> <value>执行业务方法后</value> </property> </bean> <bean id="mypointcut" class="org.springframework.aop.support.jdkregexpmethodpointcut"> <property name="patterns"> <list> <value>businessobject.dosomething</value> </list> </property> </bean> <bean id="myadvisor" class="org.springframework.aop.support.defaultpointcutadvisor"> <property name="pointcut" ref="mypointcut"/> <property name="advice" ref="myinterceptor"/> </bean> <bean id="bo" class="org.springframework.aop.framework.proxyfactorybean"> <property name="target"> <ref local="businessobjectimpl"/> </property> <property name="proxyinterfaces"> <value>businessobject</value> </property> <property name="interceptornames"> <list> <value>myinterceptor</value> <value>myadvisor</value> </list> </property> </bean> </beans><?xml version="1.0" encoding="utf-8"?> <!doctype beans public "-//spring//dtd bean//en" "http://www.springframework.org/dtd/spring-beans.dtd"> <beans> <bean id="businessobjectimpl" class="businessobjectimpl"> <property name="words"> <value>正在执行业务方法</value> </property> </bean> <bean id="myinterceptor" class="myinterceptor"> <property name="before"> <value>执行业务方法前</value> </property> <property name="after"> <value>执行业务方法后</value> </property> </bean> <bean id="mypointcut" class="org.springframework.aop.support.jdkregexpmethodpointcut"> <property name="patterns"> <list> <value>businessobject.dosomething</value> </list> </property> </bean> <bean id="myadvisor" class="org.springframework.aop.support.defaultpointcutadvisor"> <property name="pointcut" ref="mypointcut"/> <property name="advice" ref="myinterceptor"/> </bean> <bean id="bo" class="org.springframework.aop.framework.proxyfactorybean"> <property name="target"> <ref local="businessobjectimpl"/> </property> <property name="proxyinterfaces"> <value>businessobject</value> </property> <property name="interceptornames"> <list> <value>myinterceptor</value> <value>myadvisor</value> </list> </property> </bean> </beans>
8 运行main类,观察控制台输出结果,重新审查代码,反思为什么会出现这种结果。
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