apache mina 框架实例

package protocal; import java.nio.charset.Charset; import java.nio.charset.CharsetDecoder; import org.apache.mina.core.buffer.IoBuffer; import org.apache.mina.core.session.AttributeKey; import org.apache.mina.core.session.IoSession; import org.apache.mina.filter.codec.ProtocolDecoder; import org.apache.mina.filter.codec.ProtocolDecoderOutput; /** * 自定义协议-解码器 * @author Administrator * */ public class ProtocalDecoder implements ProtocolDecoder{ private final AttributeKey CONTEXT = new AttributeKey(this.getClass(), "context"); private final Charset charset; private int maxPacklength = 100; public int getMaxPacklength() { return maxPacklength; } public void setMaxPacklength(int maxPacklength) { if(maxPacklength<0){ try { throw new IllegalAccessException("maxPacklength参数："+maxPacklength); } catch (IllegalAccessException e) { e.printStackTrace(); } } this.maxPacklength = maxPacklength; } public ProtocalDecoder() { this(Charset.defaultCharset()); } public ProtocalDecoder(Charset charset) { this.charset = charset; } public Context getContext(IoSession session){ Context ctx=(Context) session.getAttribute(CONTEXT); if(ctx==null){ ctx = new Context(); session.setAttribute(CONTEXT,ctx); } return ctx; } @Override public void decode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception { final int packHeadLength=5; Context ctx = this.getContext(session); ctx.append(in); IoBuffer buf = ctx.getBuf(); buf.flip(); while(buf.remaining()>=packHeadLength){ buf.mark(); int length = buf.getInt(); byte flag = buf.get(); if(length<0||length>maxPacklength){ buf.reset(); break; }else if(length>=packHeadLength&&length-packHeadLength<=buf.remaining()){ int oldLimit = buf.limit(); buf.limit(buf.position()+length-packHeadLength); String content = buf.getString(ctx.getDecoder()); buf.limit(oldLimit); ProtocalPack pakeage = new ProtocalPack(flag, content); out.write(pakeage); }else{//半包 buf.clear(); break; } } if(buf.hasRemaining()){ IoBuffer temp = IoBuffer.allocate(maxPacklength).setAutoExpand(true); temp.put(buf); temp.flip(); buf.reset(); buf.put(temp); }else{ buf.reset(); } } @Override public void dispose(IoSession session) throws Exception { Context ctx = (Context) session.getAttribute(CONTEXT); if(ctx!=null){ session.removeAttribute(CONTEXT); } } @Override public void finishDecode(IoSession session, ProtocolDecoderOutput out) throws Exception { // TODO Auto-generated method stub } private class Context{ private final CharsetDecoder decoder; private IoBuffer buf; private Context() { decoder= charset.newDecoder(); buf=IoBuffer.allocate(80).setAutoExpand(true); } public void append(IoBuffer in){ this.getBuf().put(in); } public void rest(){ decoder.reset(); } public IoBuffer getBuf() { return buf; } public void setBuf(IoBuffer buf) { this.buf = buf; } public CharsetDecoder getDecoder() { return decoder; } } }