java如何定义发送数据包

[tiandiqing]

如何定义包头、包体，如何发送和接收？？对这块不是很清楚，请知情人给讲解下。

[9441]

自定义数据包需根据双方约定的协议进行，在协议里会定义包头，包体的长度，类型，数据校验等

发送和接收用Socket编程

[tiandiqing]

谢谢楼上，请问哪里能有这方面的资料？？

如何约定双方协议呢？

[sjyjia105]

兄弟这个是http 协议的 我原来写的 给你部分代码参考

package com.sjy.ying;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import javax.microedition.io.Connector;
import javax.microedition.io.HttpConnection;

public class MassageSend {
	
	String receiveuserid =null;
		
	String senduserid =null;
	
	String massage = null;
	
	
	public void getmassagelogin(String receiveuserid, String senduserid, String massage){
		this.receiveuserid = receiveuserid;
		this.senduserid = senduserid;
		this.massage = massage;
	}

	public void send() {

		HttpConnection hc = null;
		InputStream dis = null;
		OutputStream dos = null;
//		int temp = -1;
		String url = "http://localhost:8080/http/http";

		try {
			hc = (HttpConnection) Connector.open(url, Connector.READ_WRITE);
			hc.setRequestMethod(HttpConnection.POST);

			hc.setRequestProperty("User-Agent",
					"Profile/MIDP-1.0Configuration/CLDC-1.0");
			hc.setRequestProperty("Content-Language", "en-US");
			hc.setRequestProperty("Accept", "application/octet-stream");
			hc.setRequestProperty("Connection", "close");
			hc.setRequestProperty("Content-Length", "222");

			dos = hc.openOutputStream();
		} catch (IOException e) {
			System.out.println("网络连接失败，请查看网络连接");
		}

		try {
			dos.write('~');
			dos.write(receiveuserid.getBytes());
			dos.write(':');
			dos.write(senduserid.getBytes());
			dos.write('!');
			dos.write(massage.getBytes());
			
			System.out.println("wwwwwwwwwwwwwwww");

//			dis = hc.openInputStream();
//			StringBuffer sb = new StringBuffer();
//			while ((temp = dis.read()) != -1) {
//				// dos.write((char) temp);
//				// System.out.print((char)temp);
//				sb.append((char) temp);
//			}
//			temp = (char)dis.read();
//			System.out.println((char)temp);

			// System.out.print(temp);
			// } catch (IOException e) {
			// e.printStackTrace();

		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {

				if (dis != null)
					dis.close();
				if (dos != null)
					dos.close();
				if (hc != null)
					hc.close();
			} catch (IOException e) {
				e.printStackTrace();
			}

		}

	}

}

qq群 希望共同进步30226591

[tiandiqing]

有通过socket的吗，比如说用开源

mina或者netty等。

[kk_eclipse]

实现Mina的 MessageDecoder 接口的 decodable 方法. 这个方法就是判断是不是该去解码了, 看我的代码吧: request 对象自己定义吧, 用定长的int描述不定长的数据即可.
public class GroupUMessageDecoder implements MessageDecoder {
private static final Logger logger = org.slf4j.LoggerFactory.getLogger(MessageDecoder.class);
private Charset charset;

public GroupUMessageDecoder(Charset charset) {
this.charset = charset;
}

/**
* 检查给定的IoBuffer是否适合解码
*/
public MessageDecoderResult decodable(IoSession session, IoBuffer in) {
// 报头长度==6
if (in.remaining() < 6) {
return MessageDecoderResult.NEED_DATA;
}

// tag正常
short tag = in.getShort();
if (tag == 1 || tag == 2) {
logger.info("请求标识符：" + tag);
} else {
logger.error("未知的解码类型....");
return MessageDecoderResult.NOT_OK;
}

// 真实数据长度
int len = in.getInt();
int remainLen = in.remaining();
logger.info("dataLength:{}, remainLength:{}", len, remainLen);
if (remainLen < len) {
return MessageDecoderResult.NEED_DATA;
}
return MessageDecoderResult.OK;
}

public MessageDecoderResult decode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
logger.info("解码：" + in.toString());

CharsetDecoder decoder = charset.newDecoder();
BaseMessage message = null;
short tag = in.getShort(); // tag
int len = in.getInt(); // length
logger.info("解码数据长度:" + len);

byte[] temp = new byte[len];
in.get(temp); // 数据区

// ===============解析数据做准备======================
IoBuffer buf = IoBuffer.allocate(400).setAutoExpand(true);
buf.put(temp);
buf.flip(); // 为获取基本数据区长度做准备

if (tag == 1) { // 简单类型Message
SimpleMessageResponse resp = new SimpleMessageResponse();
String txtMessage = "";
if (len > 0) {
txtMessage = buf.getString(len, decoder);
}
resp.setTxtMessage(txtMessage);
message = resp;
}

else if (tag == 2) {
TxtImageMessageRequest resp = new TxtImageMessageRequest();
//数据部分
// 1， 文字长度描述(32bit) + 文字内容
int txtLen = buf.getInt();//文字的长度
String txtMessage = "";
if (len > 0) {
txtMessage = buf.getString(txtLen, decoder);
}
resp.setTxtMessage(txtMessage);
// 2, 图片数量
int imageNum = buf.getInt();
logger.info("received TxtMessage length:{}, message:{}, imageNum:" + imageNum, txtLen, txtMessage);
// 2， 图片部分:　图片名称长度描述 图片长度. 图片在文字内容的位置（32bit) + 图片长度描述(32bit) + 图片数据
while (imageNum-- > 0) {
int imageNameLength = buf.getInt();//图片的名称的长度
if (imageNameLength <= 0 )
break;
String imageName = buf.getString(imageNameLength, decoder);
if (imageName == null || "".equals(imageName))
break;
logger.info("imageName:{}" , imageName);
int imagePosition = buf.getInt();//图片的位置
int imageLength = buf.getInt();//图片的长度
if (imageLength <= 0)
break;
byte[] imageData = new byte[imageLength];
buf.get(imageData);

MessageImageInfo ii = new MessageImageInfo();
ii.setImageName(imageName);
ii.setImagePositionInTxt(imagePosition);
ii.setImageData(imageData);
resp.addImageInfo(ii);
message = resp;
break;
}

}


out.write(message);
// ================解码成功=========================
return MessageDecoderResult.OK;
}

public void finishDecode(IoSession session, ProtocolDecoderOutput out)
throws Exception {
}
}



public class GroupUMessageEncoder implements MessageEncoder<BaseMessage> {

private static final Logger log = org.slf4j.LoggerFactory.getLogger(GroupUMessageEncoder.class);
private Charset charset;

public GroupUMessageEncoder(Charset charset) {
this.charset = charset;
}

public void encode(IoSession session, BaseMessage message,
ProtocolEncoderOutput out) throws Exception {

IoBuffer buf = IoBuffer.allocate(400).setAutoExpand(true);

// ===========SimpleMessageRequest 编码数据区===============
if (message instanceof SimpleMessageRequest) {
SimpleMessageRequest req = (SimpleMessageRequest) message;
buf.putShort((short) req.getTag());
int dataLength = req.getLen(charset);
buf.putInt(dataLength);
log.info("SimpleMessageRequest dataLength:" + dataLength);
buf.putString(req.getTxtMessage(), charset.newEncoder());
log.info("SimpleMessageRequest　编码完毕:" + buf.toString());
}

// ===========TxtImageMessageRequest 编码数据区===============
if (message instanceof TxtImageMessageRequest) {
TxtImageMessageRequest req = (TxtImageMessageRequest) message;
buf.putShort((short) req.getTag());
int dataLength = req.getLen(charset);
buf.putInt(dataLength);
System.out.println("dataLength:" + dataLength);

//数据部分
// 1， 文字长度描述(32bit) + 文字内容
int txtLength = req.getTxtMessage().getBytes(charset).length;
buf.putInt(txtLength);
buf.putString(req.getTxtMessage(), charset.newEncoder());
// 2, 图片数量
buf.putInt(req.getImageNum());
// 3， 图片部分:　图片名称长度描述 图片长度. 图片在文字内容的位置（32bit) + 图片长度描述(32bit) + 图片数据
if (req.getImageList() != null && req.getImageList().size() > 0) {
for (MessageImageInfo mii : req.getImageList()) {
if (mii.getImageData() == null || mii.getImageData().length == 0){
log.warn("TxtImageMessageRequest Encode:　ｉｍａｇｅ　ｎｏ　ｄａｔａ");
continue;
}
int imageNameLength = mii.getImageName().getBytes(charset).length;
buf.putInt(imageNameLength); //图片名称长度
buf.putString(mii.getImageName(), charset.newEncoder()); //图片名称

buf.putInt(mii.getImagePositionInTxt()); //图片位置
buf.putInt(mii.getImageData().length); //图片数据长度
buf.put(mii.getImageData()); //图片数据
}
}
log.info("TxtImageMessageRequest编码完毕:" + buf.toString());
}

buf.flip();
out.write(buf);
}
}