详解Java的TCP/IP编程学习--基于定界符的成帧

package framer;import java.io.IOException;import java.io.OutputStream;public interface Framer {  /**   * 添加成帧信息并将指定消息输出到指定流   * @param message   * @param out   * @throws IOException   */  void frameMsg(byte[] message, OutputStream out) throws IOException;  /**   * 扫描指定的流，从中抽取下一条信息   * @return   * @throws IOException   */  byte[] nextMsg() throws IOException;}

package framer;import java.io.*;/** * @ClassName DelimFramer * @Description TODO * @Author Cays * @Date 2019/3/16 22:04 * @Version 1.0 **/public class DelimFramer implements Framer {  //输入流  private InputStream in;  //定界符为换行符  private static final byte DELIMITER='/n';  public DelimFramer(InputStream in) {    this.in = in;  }  @Override  public void frameMsg(byte[] message, OutputStream out) throws IOException {    //检测信息中是否包含换行符    for (byte b:message){      if (b==DELIMITER){        throw new IOException("Message contaions delimiter");      }    }    //将成帧的信息输出到流中    out.write(message);    //添加定界符    out.write(DELIMITER);    out.flush();  }  @Override  public byte[] nextMsg() throws IOException {    ByteArrayOutputStream messageBuffer=new ByteArrayOutputStream();    int nextByte;    //读取流中的每一个字节，直到遇到定界符    while ((nextByte=in.read())!=DELIMITER){      if (nextByte==-1){        //如果遇到定界符之前就到了流的终点        if (messageBuffer.size()==0){          return null;        }else {          //如果存入缓存区之前有数据，抛出异常          throw new EOFException("Non-empty message without delimiter");        }      }      //将无定界符的字节写入消息缓存区      messageBuffer.write(nextByte);    }    //将消息缓存区的内容以字节数组的形式返回    return messageBuffer.toByteArray();  }}