JAVA的動態(tài)代理分析
引導語:在使用動態(tài)代理類時,我們必須實現(xiàn)InvocationHandler接口,以下是百分網(wǎng)小編分享給大家的JAVA動態(tài)代理,歡迎閱讀了解!
1,被代理類 的接口 Proxied
Java代碼
package Test1;
/pic/p>
public interface Proxied {
void doSomething();
void doSomethingElse(String str);
}
2,一個 Proxied接口 的實現(xiàn)類(被代理類)
Java代碼
package Test1;
public class ConcreteProxied implements Proxied {
@Override
public void doSomething() {
try {
Thread.sleep(100);
} catch (InterruptedException e) {
System.err.println("Error : InterruptedException");
}
System.out.println(this.getClass().getSimpleName()
+ " >> doSomething .");
}
@Override
public void doSomethingElse(String str) {
try {
Thread.sleep(150);
} catch (InterruptedException e) {
System.err.println("Error : InterruptedException");
}
System.out.println(this.getClass().getSimpleName()
+ " >> doSomethingElse , argument = " + str + ".");
}
}
3,TimingInvocationHandler 類,實現(xiàn)了 InvocationHandler 接口
Java代碼
package Test1;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
public class TimeingInvocationHandler implements InvocationHandler{
/pic/p>
private Object proxied;
public TimeingInvocationHandler(Object proxied){
this.proxied = proxied;
}
/pic/p>
/pic/p>
/pic/p>
@Override
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
System.out.println(method.getDeclaringClass().getName());
long currentTimeMillis = System.currentTimeMillis();
Object ret = method.invoke(proxied, args);
System.out.println(this.getClass().getSimpleName()+" >> wastes time : "
+(System.currentTimeMillis() - currentTimeMillis)+"ms");
return ret;
}
}
4,測試類 Test
Java代碼
package Test1;
import java.lang.reflect.Proxy;
public class TestProxy {
public static void main(String[] args) {
Proxied proxied = new ConcreteProxied();
proxied.doSomething();
proxied.doSomethingElse("only a String");
/pic/p>
/pic/p>
Proxied proxy = (Proxied) Proxy.newProxyInstance(Proxied.class
.getClassLoader(), /pic/p>
new Class[] { Proxied.class }, /pic/p>
new TimeingInvocationHandler(proxied) /pic/p>
);
proxy.doSomething();
proxy.doSomethingElse("only a String");
}
}
運行Test類,輸出如下:
ConcreteProxied >> doSomething .
ConcreteProxied >> doSomethingElse , argument = only a String.
Test1.Proxied
ConcreteProxied >> doSomething .
TimeingInvocationHandler >> wastes time : 110ms
Test1.Proxied
ConcreteProxied >> doSomethingElse , argument = only a String.
TimeingInvocationHandler >> wastes time : 156ms
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