查看本类的 API文档回源码主页

   /*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   https://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package io.netty.example.factorial;
  
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.SimpleChannelInboundHandler;
  
  import java.math.BigInteger;
  
  /**
   * Handler for a server-side channel.  This handler maintains stateful
   * information which is specific to a certain channel using member variables.
   * Therefore, an instance of this handler can cover only one channel.  You have
   * to create a new handler instance whenever you create a new channel and insert
   * this handler  to avoid a race condition.
   */
  public class FactorialServerHandler extends SimpleChannelInboundHandler<BigInteger> {
  
      private BigInteger lastMultiplier = new BigInteger("1");
      private BigInteger factorial = new BigInteger("1");
  
      @Override
      public void channelRead0(ChannelHandlerContext ctx, BigInteger msg) throws Exception {
          // Calculate the cumulative factorial and send it to the client.
          lastMultiplier = msg;
          factorial = factorial.multiply(msg);
          ctx.writeAndFlush(factorial);
      }
  
      @Override
      public void channelInactive(ChannelHandlerContext ctx) throws Exception {
          System.err.printf("Factorial of %,d is: %,d%n", lastMultiplier, factorial);
      }
  
      @Override
      public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
          cause.printStackTrace();
          ctx.close();
      }
  }