前面一篇博客里面已经介绍过SSDP协议原理，本篇博客将实现实现Android上的SSDP协议。

关键技术分析：1、发送广播；须要发送送广播，所以须要使用MulticastSocket、SocketAddress、InetAddress，须要掌握。

2、SSDP数据报格式；标准的SSDP Server解析的时候对于分段的字段选用的特征码是"\r\n"，须要特别注意。

3、訪问权限；须要互联网，要在Mainfest中加入�联网的相关权限。

下面是我的源代码：

1、SSDPConstants.java

public class SSDPConstants {

/* New line definition */

public static final String NEWLINE = "\r\n";

public static final String ADDRESS = "239.255.255.250";

public static final int PORT = 1900;

public static final String SL_MSEARCH = "M-SEARCH * HTTP/1.1";

public static final String SL_OK = "HTTP/1.1 200 OK";

public static final String ST_Product = "ST:urn:schemas-upnp-org:device:Server:1";

public static final String Found = "ST=urn:schemas-upnp-org:device:";

public static final String Root = "ST:urn:schemas-upnp-org:device:DZBA_HomeDP:1";

}

2、SSDPSearchMsg .java

public class SSDPSearchMsg {

static final String HOST = "Host:" + SSDP.ADDRESS + ":" + SSDP.PORT;

static final String MAN = "Man:\"ssdp:discover\"";

static final String NEWLINE = "\r\n";

int mMX = 5; /* seconds to delay response */

String mST; /* Search target */

public SSDPSearchMsg(String ST) {

mST = ST;

}

public int getmMX() {

return mMX;

}

public void setmMX(int mMX) {

this.mMX = mMX;

}

public String getmST() {

return mST;

}

public void setmST(String mST) {

this.mST = mST;

}

@Override

public String toString() {

StringBuilder content = new StringBuilder();

content.append(SSDP.SL_MSEARCH).append(NEWLINE);

content.append(HOST).append(NEWLINE);

content.append(MAN).append(NEWLINE);

content.append("MX:" + mMX).append(NEWLINE);

content.append(mST).append(NEWLINE);

content.append(NEWLINE);

return content.toString();

}

}

3、SSDPSocket .java

public class SSDPSocket {

SocketAddress mSSDPMulticastGroup;

MulticastSocket mSSDPSocket;

InetAddress broadcastAddress;

public SSDPSocket() throws IOException {

mSSDPSocket = new MulticastSocket(58000); // Bind some random port for receiving datagram

broadcastAddress = InetAddress.getByName(SSDPConstants.ADDRESS);

mSSDPSocket.joinGroup(broadcastAddress);

}

/* Used to send SSDP packet */

public void send(String data) throws IOException {

DatagramPacket dp = new DatagramPacket(data.getBytes(), data.length(), broadcastAddress, SSDPConstants.PORT);

mSSDPSocket.send(dp);

}

/* Used to receive SSDP packet */

public DatagramPacket receive() throws IOException {

byte[] buf = new byte[1024];

DatagramPacket dp = new DatagramPacket(buf, buf.length);

mSSDPSocket.receive(dp);

return dp;

}

public void close() {

if (mSSDPSocket != null) {

mSSDPSocket.close();

}

}

}

4、SSDP .java

public class SSDP {

/* New line definition */

public static final String NEWLINE = "\r\n";

public static final String ADDRESS = "239.255.255.250";

public static final int PORT = 1900;

public static final String ST = "ST";

public static final String LOCATION = "LOCATION";

public static final String NT = "NT";

public static final String NTS = "NTS";

/* Definitions of start line */

public static final String SL_NOTIFY = "NOTIFY * HTTP/1.1";

public static final String SL_MSEARCH = "M-SEARCH * HTTP/1.1";

public static final String SL_OK = "HTTP/1.1 200 OK";

@SuppressWarnings("resource")

public static String parseHeaderValue(String content, String headerName) {

Scanner s = new Scanner(content);

s.nextLine(); // Skip the start line

while (s.hasNextLine()) {

String line = s.nextLine();

int index = line.indexOf(':');

String header = line.substring(0, index);

if (headerName.equalsIgnoreCase(header.trim())) {

return line.substring(index + 1).trim();

}

}

return null;

}

public static String parseHeaderValue(DatagramPacket dp, String headerName) {

return parseHeaderValue(new String(dp.getData()), headerName);

}

@SuppressWarnings("resource")

public static String parseStartLine(String content) {

Scanner s = new Scanner(content);

return s.nextLine();

}

public static String parseStartLine(DatagramPacket dp) {

return parseStartLine(new String(dp.getData()));

}

}

5、MainActivity .java

public class MainActivity extends Activity implements OnClickListener {

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

WifiManager wm = (WifiManager) getSystemService(Context.WIFI_SERVICE);

WifiManager.MulticastLock multicastLock = wm.createMulticastLock("multicastLock");

multicastLock.setReferenceCounted(true);

multicastLock.acquire();

setContentView(R.layout.activity_main);

((Button) this.findViewById(R.id.btnSendSSDPSearch)).setOnClickListener(this);

}

@Override

public void onClick(View v) {

switch (v.getId()) {

case R.id.btnSendSSDPSearch:

new Thread(new Runnable() {

@Override

public void run() {

SendMSearchMessage();

}

}).start();

default:

break;

}

}

private void SendMSearchMessage() {

// SSDPSearchMsg searchContentDirectory = new SSDPSearchMsg(SSDPConstants.ST_ContentDirectory);

// SSDPSearchMsg searchAVTransport = new SSDPSearchMsg(SSDPConstants.ST_AVTransport);

SSDPSearchMsg searchProduct = new SSDPSearchMsg(SSDPConstants.Root);

SSDPSocket sock = null;

try {

sock = new SSDPSocket();

for (int i = 0; i < 2; i++) {

// sock.send(searchContentDirectory.toString());

// sock.send(searchAVTransport.toString());

sock.send(searchProduct.toString());

//String s = "M-SEARCH * HTTP/1.1 \n HOST= 239.255.255.250:1900 \n MAN= \"ssdp:discover\" \n MX: 3 \n ST= upnp:rootdevice";

//sock.send(s);

Log.i("-------------", "发送的数据为：\n" + searchProduct.toString());

}

while (true) {

DatagramPacket dp = sock.receive(); // Here, I only receive the same packets I initially sent above

String c = new String(dp.getData()).trim();

String ip = new String(dp.getAddress().toString()).trim();

Log.i("------------", "接收到的数据为：\n" + c + "數據來源IP：" + ip);

}

} catch (IOException e) {

Log.e("M-SEARCH", e.getMessage());

}

}

}

界面xml非常easy，仅仅有一个button

Mainfest.xml:

package="com.example.ssdp"

android:versionCode="1"

android:versionName="1.0" >

android:minSdkVersion="8"

android:targetSdkVersion="18" />

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" >

android:name="com.example.ssdp.MainActivity"

android:label="@string/app_name" >

使用须知：须要有Server端执行，http://download.csdn.net/detail/zhu530548851/7451201下载源代码，该源代码是js的。

将Server放于Linux系统文件夹下，进入test文件夹，运行node server.js就可以。

须要Linux安装有nodejs:sudo apt-get install nodejs

这样在执行Androidclient就能够从Log中看到来自于Server的信息了。

Android源代码在此：http://download.csdn.net/detail/zhu530548851/7451179

个人辛勤劳动成果，如有转载，请注明出处，谢谢！