Spring AOP的底层实现技术(1)

package com.baobaotao.proxy;
public class ForumServiceImpl implements ForumService ...{
public void removeTopic(int topicId) ...{
//开始性能监视
PerformanceMonitor.begin("com.baobaotao.proxy.ForumServiceImpl.removeTopic");
System.out.println("模拟删除Topic记录:"+topicId);
try ...{
Thread.currentThread().sleep(20);
} catch (Exception e) ...{
throw new RuntimeException(e);
}
//结束监视、并给出性能报告信息
PerformanceMonitor.end();
}
public void removeForum(int forumId) ...{
//开始性能监视
PerformanceMonitor.begin("com.baobaotao.proxy.ForumServiceImpl.removeForum");
System.out.println("模拟删除Forum记录:"+forumId);
try ...{
Thread.currentThread().sleep(40);
} catch (Exception e) ...{
throw new RuntimeException(e);
}
//结束监视、并给出性能报告信息
PerformanceMonitor.end();
}
}

package com.baobaotao.proxy;
public class PerformanceMonitor {
//通过一个ThreadLocal保存线程相关的性能监视信息
private static ThreadLocal<MethodPerformace> performaceRecord =
new ThreadLocal<MethodPerformace>();
public static void begin(String method) {
System.out.println("begin monitor...");
MethodPerformace mp = new MethodPerformace(method);
performaceRecord.set(mp);
}
public static void end() {
System.out.println("end monitor...");
MethodPerformace mp = performaceRecord.get();
mp.printPerformace(); //打印出业务方法性能监视的信息
}
}

package com.baobaotao.proxy;
public class MethodPerformace {
private long begin;
private long end;
private String serviceMethod;
public MethodPerformace(String serviceMethod){
this.serviceMethod = serviceMethod;
this.begin = System.currentTimeMillis();//记录方法调用开始时的系统时间
}
public void printPerformace(){
//以下两行程序得到方法调用后的系统时间，并计算出方法执行花费时间
end = System.currentTimeMillis();
long elapse = end - begin;
//报告业务方法执行时间
System.out.println(serviceMethod+"花费"+elapse+"毫秒。");
}
}