com.sun.proxy.$Proxy0 cannot be cast to ...

Bertha 。 2021-08-11 17:35 853阅读 0赞

【错误提示】

Exception in thread "main" java.lang.ClassCastException: com.sun.proxy.$Proxy0 cannot be cast to proxy.test.Bank
    	at proxy.test.ProxyTest2.main(ProxyTest2.java:40)

【报错代码】

package proxy.test;
    
    import java.lang.reflect.InvocationHandler;
    import java.lang.reflect.Method;
    import java.lang.reflect.Proxy;
    
    /*
     * 自测
     */
    interface Bank{
    	public void loan(String name,int money) ;
    }
    
    class Creditor implements Bank{
    
    	@Override
    	public void loan(String name,int money) {
    		// TODO Auto-generated method stub
    		System.out.println("贷款人："+name+",贷款金额（万元）:"+money);
    	}
    }
    
    class MyInvocationHandler2 implements InvocationHandler{
    	private Object obj;
    	
    	public MyInvocationHandler2(Object obj) {
    		this.obj=obj;
    	}
    
    	@Override
    	public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    		// TODO Auto-generated method stub
    		return method.invoke(obj, args);
    	}
    }
    public class ProxyTest2 {
    	public static void main(String[] args) {
    		Bank credictor=new Creditor();
    		InvocationHandler handler=new MyInvocationHandler2(credictor);
    		Bank bank=(Bank)Proxy.newProxyInstance(Bank.class.getClassLoader(), Bank.class.getInterfaces(), handler);
    		bank.loan("王二小", 300);
    	}
    }

【错误改正】

将main方法中
    Bank bank=(Bank)Proxy.newProxyInstance(Bank.class.getClassLoader(), Bank.class.getInterfaces(), handler);
    
    改为：
    
    Bank bank=(Bank)Proxy.newProxyInstance(credictor.getClass().getClassLoader(), credictor.getClass().getInterfaces(), handler);

【错误原因】

loader：代表与目标对象相同的类加载器-------目标对象.getClass().getClassLoader()

上述中的目标对象为credictor(贷款者)

【正确输出】

![20190902130135516.png][]

[20190902130135516.png]: /images/20210811/b4bc6ef2697b4050958faa5da8dc7447.png