项目目录结构
项目下载
https://github.com/cbeann/Demoo/tree/master/async-demo
实践
pom
<!-- https://mvnrepository.com/artifact/cglib/cglib --> <!--cglib依赖--> <dependency> <groupId>cglib</groupId> <artifactId>cglib</artifactId> <version>2.2.2</version> </dependency>
自定义标注注解
没有方法参数的注解成为标注注解
//Async注解 @Target(ElementType.METHOD)//方法注解 @Retention(RetentionPolicy.RUNTIME)//运行时注解 public @interface MyAsyncInterface { }
自定义执行器
package com.imooc.demo.executor; import net.sf.cglib.proxy.MethodProxy; import java.lang.reflect.Method; import java.util.concurrent.FutureTask; public class MyExecutor { /* 动态代理的异步执行方法，参数就是 invoke(Object proxy, Method method, Object[] args) */ public static void submit(Object object, Method method, Object[] args) throws Exception { //封装成callable接口 MyDyCallable myCallable = new MyDyCallable(object, method, args); FutureTask futureTask = new FutureTask(myCallable); //运行线程 new Thread(futureTask).start(); } /* cglib的异步执行方法intercept(Object object, Method method, Object[] args, MethodProxy proxy) */ public static void submit(Object object, Method method, Object[] args, MethodProxy proxy) throws Exception { //封装成callable接口 MyCglibCallable myCglibCallable = new MyCglibCallable(object, method, args, proxy); FutureTask futureTask = new FutureTask(myCglibCallable); //运行线程 new Thread(futureTask).start(); } }
实现动态代理的异步执行
IEmailService接口
public interface IEmailService { public void sendEmail(); public void speak(); }
IEmailService接口实现类
其中带有MyAsyncInterface我们要使其成为异步方法
package com.imooc.demo.dyproxy; import com.imooc.demo.myinterface.MyAsyncInterface; public class EmailService implements IEmailService { @MyAsyncInterface @Override public void sendEmail() { System.out.println("开始发送email---------->睡10秒"); try { //处理业务10毫秒 Thread.sleep(1000 * 2); } catch (Exception e) { } System.out.println("结束发发送email<----------"); } public void speak() { System.out.println("-----EmailService------"); } }
MyAsyncHandler （动态代理知识）
package com.imooc.demo.dyproxy; import com.imooc.demo.myinterface.MyAsyncInterface; import com.imooc.demo.executor.MyExecutor; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; public class MyAsyncHandler implements InvocationHandler { //目标对象 private Object target; //传入代码目标对象 public MyAsyncHandler(Object object) { this.target = object; } @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable, Exception { //method参数是接口的方法，上面是不带@MyAsyncInterface的，我们一般是定义在接口实现类上，所以我们通过接口的method获取target(实现类)的方法，从而获取自定义注解信息 MyAsyncInterface annotation = target.getClass().getMethod(method.getName(), method.getParameterTypes()).getAnnotation(MyAsyncInterface.class); if (null != annotation) { //如果该方法有自定义异步注解，启动线程跑 MyExecutor.submit(target, method, args); } else { //如果该方法没有自定义异步注解，同步执行 Object invoke = method.invoke(target, args); } //如果有结果返回，如果没有就不返回 return null; } }
MyDyCallable：实现Callable接口（多线程知识）
目的：如果方法时异步，将参数传入callable,并且启动线程执行
package com.imooc.demo.executor; import java.lang.reflect.Method; import java.util.concurrent.Callable; public class MyDyCallable implements Callable<Object> { private Object target; private Method method; private Object[] args; public MyDyCallable(Object object, Method method, Object[] args) { this.target = object; this.method = method; this.args = args; } @Override public Object call() throws Exception { Object result = method.invoke(target, args); return result; } }
ProxyStart：测试类
package com.imooc.app; import com.imooc.demo.dyproxy.EmailService; import com.imooc.demo.dyproxy.IEmailService; import com.imooc.demo.dyproxy.MyAsyncHandler; import java.lang.reflect.Proxy; public class ProxyStart { public static void main(String[] args) { IEmailService emailService = new EmailService(); MyAsyncHandler asyncHandler = new MyAsyncHandler(emailService); Class cls = emailService.getClass(); //创建动态代理对象 IEmailService newProxyInstance = (IEmailService) Proxy.newProxyInstance( cls.getClassLoader(), cls.getInterfaces(), asyncHandler); //此方法时异步 newProxyInstance.sendEmail(); //此方法时同步 newProxyInstance.speak(); // 执行结果如下： // -----EmailService------ newProxyInstance.speak()方法 // 开始发送email---------->睡10秒 newProxyInstance.sendEmail();方法 // 结束发发送email<---------- } }
实现cglib的异步执行
MQService
方法setMessage方法，我们使其成为异步方法
package com.imooc.demo.cglibproxy; import com.imooc.demo.myinterface.MyAsyncInterface; public class MQService { @MyAsyncInterface public void setMessage(String messgae) { System.out.println("开始发送MQmessage--------->睡3秒"); try { Thread.sleep(1000 * 3); } catch (Exception e) { } System.out.println("结束发送MQmessage<-------------"); } }
CGlibProxy （动态代理cglib知识）
package com.imooc.demo.cglibproxy; import com.imooc.demo.executor.MyExecutor; import com.imooc.demo.myinterface.MyAsyncInterface; import net.sf.cglib.proxy.Enhancer; import net.sf.cglib.proxy.MethodInterceptor; import net.sf.cglib.proxy.MethodProxy; import java.lang.reflect.Method; public class CGlibProxy implements MethodInterceptor { private Enhancer enhancer = new Enhancer(); public Object getProxy(Class clz) { enhancer.setSuperclass(clz); enhancer.setCallback(this); return enhancer.create(); } /** * @param object 目标类的实例 * @param method 目标方法的反射对象 * @param args 目标方法的参数 * @param proxy 代理类的实例 * @return * @throws Throwable */ @Override public Object intercept(Object object, Method method, Object[] args, MethodProxy proxy) throws Throwable { if (method.getAnnotation(MyAsyncInterface.class) != null) { MyExecutor.submit(object, method, args, proxy); } else { proxy.invokeSuper(object, args); } return null; } }
MyCglibCallable (多线程知识)
package com.imooc.demo.executor; import net.sf.cglib.proxy.MethodProxy; import java.lang.reflect.Method; import java.util.concurrent.Callable; public class MyCglibCallable implements Callable { private Object object; private Method method; private Object[] args; private MethodProxy proxy; //参数是intercept(Object object, Method method, Object[] args, MethodProxy proxy) public MyCglibCallable(Object object, Method method, Object[] args, MethodProxy proxy) { this.object = object; this.args = args; this.method = method; this.proxy = proxy; } @Override public Object call() { try { proxy.invokeSuper(object, args); } catch (Throwable throwable) { throwable.printStackTrace(); } return null; } }
CGlibStart 测试类
package com.imooc.app; import com.imooc.demo.cglibproxy.CGlibProxy; import com.imooc.demo.cglibproxy.MQService; public class CGlibStart { public static void main(String[] args) { // MQService mqService = new MQService(); // mqService.setMessage("123123"); CGlibProxy cGlibProxy = new CGlibProxy(); MQService proxy = (MQService) cGlibProxy.getProxy(MQService.class); proxy.setMessage("123"); System.out.println("-----------------------"); // 执行结果 // ----------------------- System.out.println("-----------------------"); // 开始发送MQmessage--------->睡3秒 proxy.setMessage("123"); // 结束发送MQmessage<------------- } }
总结
1）需要了解动态代理、多线程知识
2）上面都是按照方法没有返回结果算的，实际情况下是很多是有结果的
3）多线程中Callable是有返回结果的
