Java - 将类型化列表转换为数组

Question

这是我的方法

public AuctionItem[] getOpenAuctions() throws RemoteException {

    return itemList.toArray((AuctionItem[]) java.lang.reflect.Array
            .newInstance(itemList.getClass(), itemList.size()));

}

这是我的错误

Exception in thread "main" java.lang.ClassCastException: [Ljava.util.LinkedList; cannot be cast to [LAuction.AuctionItem;
at Auction.AuctionImpl.getOpenAuctions(AuctionImpl.java:44)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
at sun.rmi.transport.Transport$1.run(Unknown Source)
at sun.rmi.transport.Transport$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Unknown Source)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Source)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Unknown Source)
at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
at sun.rmi.server.UnicastRef.invoke(Unknown Source)
at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Unknown Source)
at java.rmi.server.RemoteObjectInvocationHandler.invoke(Unknown Source)
at $Proxy0.getOpenAuctions(Unknown Source)
at Seller.SellerMain.main(SellerMain.java:38)

它出什么问题了？

Answer 1

尝试:

return itemList.toArray(new AuctionItem[itemList.size()]);

您编写的代码的问题是itemList.getClass()返回类LinkedList.所以这个Array.newInstance()方法正在创建一个LinkedList[],然后你试图将其类型化为一个AuctionItem[].由于这两种类型与赋值不兼容,因此抛出一个ClassCastException.