java NIO help me!!!

Question

if((count = selector.select()) > 0) {
             iterator = selector.selectedKeys().iterator();
             while(iterator.hasNext()){
               SelectionKey key = (SelectionKey)iterator.next();
 else if(key.isWritable()){
               //if((key.readyOps() & SelectionKey.OP_WRITE)==SelectionKey.OP_WRITE){
                 System.out.println(key.toString()+":即将写的操作,是否合法.................."+key.isValid());
                 WriterHandler.addWriter((ClientRequest)key.attachment());
                 key.cancel();
--------------------------------------------------------
写了之后 key.cancel();

Answer 1

楼上的这句话：
SelectionKey key = (SelectionKey)iterator.next();
后边加上一句：
iterator.remove();