public abstract class Dog implements Eat {
protected String name;
protected int age;
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;
}
}
public interface Eat {
void gotoEat();
void gotoEat(String food);
void gotoEat(String food, int num);
}
public class BorderCollie extends Dog {
@Override
public void gotoEat() {
System.out.println("什么都不喂我,只能吃草...");
}
@Override
public void gotoEat(String food) {
System.out.println(food + "吃饱了,牧羊so easy!");
}
@Override
public void gotoEat(String food, int num) {
System.out.println("足足吃了" + num + "份" + food + ",本边牧需要散步消化");
}
}
public class EatHandler implements InvocationHandler {
private Object target = null;
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
if ("gotoEat".equals(method.getName()) && args != null) {
if(args.length == 2){
System.out.println("这里是调用方法名为:" + method.getName() + ";参数个数为:" + args.length);
Class<?>[] parameterTypes = method.getParameterTypes();
List<String> argsType = Stream.of(parameterTypes).map(Class::getName).collect(Collectors.toList());
argsType.stream().forEach(System.out::println);
}
}
System.out.println("先要洗爪...");
Object result = method.invoke(target, args);
System.out.println("吃饱后要记得散步...");
return result;
}
public EatHandler(Object target) {
this.target = target;
}
public void setTarget(Object target) {
this.target = target;
}
public Object getTarget() {
return target;
}
}
@Test
public void dogEat() {
Dog borderCollie = new BorderCollie();
ClassLoader classLoader = BorderCollie.class.getClassLoader();
Class<?>[] interfaces = BorderCollie.class.getInterfaces();
EatHandler eatHandler = new EatHandler(borderCollie);
Object proxyInstance = Proxy.newProxyInstance(classLoader, interfaces, eatHandler);
BorderCollie obj = (BorderCollie) proxyInstance;
System.out.println(proxyInstance.getClass().getName());
}
错误信息:
java.lang.ClassCastException: com.sun.proxy.$Proxy4 cannot be cast to myproxy.BorderCollie
at myproxy.EatTest.dogEat2(EatTest.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
我估计着是:BorderCollie obj = (BorderCollie) proxyInstance;这句话出错了,但是搞不懂为什么啊?