Android SocketChannel使用

Socket 安卓開發 · 發表 2019-04-22 10:25:58

摘要：一概述：是一種面向流連線只sockets套接字的可選擇通道。是基於TCP連線傳輸，主要用來處理網路I/O的通道，實現了可選擇通道，可以被多路複用。二特徵： 1 對於已經存在的socket不能建立SocketChannel 2 SocketChanne...

一概述：

是一種面向流連線只sockets套接字的可選擇通道。是基於TCP連線傳輸，主要用來處理網路I/O的通道，實現了可選擇通道，可以被多路複用。

二特徵：

1 對於已經存在的socket不能建立SocketChannel

2 SocketChannel中提供的open介面建立的Channel並沒有進行網路級聯，需要使用connect介面連線到指定地址

3 未進行連線的SocketChannle執行I/O操作時，會丟擲NotYetConnectedException

4 SocketChannel支援兩種I/O模式：阻塞式和非阻塞式

5 SocketChannel支援非同步關閉。如果SocketChannel在一個執行緒上read阻塞，另一個執行緒對該SocketChannel呼叫shutdownInput，則讀阻塞的執行緒將返回-1表示沒有讀取任何資料；如果SocketChannel在一個執行緒上write阻塞，另一個執行緒對該SocketChannel呼叫shutdownWrite，則寫阻塞的執行緒將丟擲AsynchronousCloseException

三 SocketChannel的使用：

（1）建立

Selector mSelector = Selector.open();

InetSocketAddress inetSocketAddress =new InetSocketAddress(mRemoteIp, Constants.TCP_PORT);

SocketChannel socketChannel= SocketChannel.open(inetSocketAddress);

 socketChannel.configureBlocking(false);

 socketChannel.register(mSelector, SelectionKey.OP_READ);

(2) 連線校驗

socketChannel.isOpen();// 測試SocketChannel是否為open狀態socketChannel.isConnected();//測試SocketChannel是否已經被連線socketChannel.isConnectionPending();//測試SocketChannel是否正在進行連線socketChannel.finishConnect();//校驗正在進行套接字連線的SocketChannel是否已經完成連線

(3) 讀寫模式

前面提到SocketChannel支援阻塞和非阻塞兩種模式：

socketChannel.configureBlocking(false);

主要是通過以上方法設定SocketChannel的讀寫模式。false表示非阻塞，true表示阻塞。

(4) 讀寫

SocketChannel socketChannel = SocketChannel.open(newInetSocketAddress("www.baidu.com",8080));
ByteBuffer byteBuffer = ByteBuffer.allocate(16);
socketChannel.read(byteBuffer);
socketChannel.close();
System.out.println("test end!");

以上為阻塞式讀，當執行到read出，執行緒將阻塞，控制檯將無法列印test end！。

SocketChannel socketChannel =SocketChannel.open(newInetSocketAddress("www.baidu.com",8080));socketChannel.configureBlocking(false);
ByteBuffer byteBuffer = ByteBuffer.allocate(16);
socketChannel.read(byteBuffer);
socketChannel.close();
System.out.println("test end!");

以上為非阻塞讀，控制檯將列印test end!。

讀寫都是面向緩衝區，這個讀寫方式與前文中的FileChannel一樣，這裡不再贅述。

(5) 設定和獲取引數

socketChannel.setOption(StandardSocketOptions.SO_KEEPALIVE,Boolean.TRUE).setOption(StandardSocketOptions.TCP_NODELAY,Boolean.TRUE);

通過setOptions方法可以設定socket套接字的相關引數。

socketChannel.getOption(StandardSocketOptions.SO_KEEPALIVE)socketChannel.getOption(StandardSocketOptions.SO_RCVBUF)

可以通過getOption獲取相關引數的值。如預設的接收緩衝區大小是8192byte。

四一個完整的例子

package com.zongmu.rpa.probes;

import android.text.TextUtils;

import com.google.protobuf.InvalidProtocolBufferException;
import com.google.protobuf.Message;
import com.google.protobuf.RpcCallback;
import com.zongmu.rpa.constant.Constants;
import com.zongmu.rpa.model.ProtoPackage;
import com.zongmu.rpa.probes.callback.TcpConnCallback;
import com.zongmu.rpa.utils.ByteUtils;
import com.zongmu.rpa.utils.LogUtil;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;

public class TcpProbes implements ZmProbes {
private static String TAG = "TcpProbes";
private Selector mSelector;
private SocketChannel mSocketChannel;
private String mRemoteIp;
private int mRecvLength = -1;
private TcpConnCallback mCallback;
private ProtoPackage mProtoPackage;

public void setTcpConnCallback(TcpConnCallback callback){
mCallback = callback;
}

public Selector getSelector() {
return mSelector;
}

public String getRemoteIp() {
return mRemoteIp;
}

public void setRemoteIp(String ip) {
this.mRemoteIp = ip;
}

@Override
public void sendData(final byte[] pkg) {
if (mSocketChannel.isOpen() && mSocketChannel.isConnected()) {
new Thread(new Runnable() {
@Override
public void run() {
try {
mSocketChannel.write(ByteBuffer.wrap(pkg));
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
}
}

@Override
public int receData(Message responsePrototype,RpcCallback<Message>done) {
if (mSocketChannel == null || !mSocketChannel.isOpen()|| !mSocketChannel.isConnected()){
return Constants.SOCKET_NOT_CONNECT;
}
int ret = -1;
try {
ret = mSelector.select(3000);
} catch (IOException e) {
e.printStackTrace();
}
if(ret < 0){
return Constants.RECEIVE_DATA_TIMEOUT;
}
byte[] recvData = new byte[512];
Iterator<SelectionKey> iterator = mSelector.selectedKeys().iterator();
while(iterator.hasNext()) {
SelectionKey key = iterator.next();
if(key.isValid()) {
if(key.isReadable()) {
LogUtil.e(TAG, "receive data");
try {
mRecvLength = mSocketChannel.read(ByteBuffer.wrap(recvData));
} catch (IOException e) {
e.printStackTrace();
}
LogUtil.e(TAG, "Received data size: " + mRecvLength);
}
}else {
LogUtil.e(TAG, "wait server response timeout");
mRecvLength = -1;
recvData = null;
}
if (!iterator.hasNext()) {
break;
}
}

if(mProtoPackage == null){
mProtoPackage = new ProtoPackage();
}
String raw_data = new String(recvData, 0, mRecvLength);
LogUtil.e(TAG, "RawPackage:" + raw_data);
LogUtil.e(TAG, "RawPackage:" + ByteUtils.bytes2HexString(ByteUtils.getSubArrays(recvData,0,mRecvLength)));
String data = new String(recvData, 0, 13);
LogUtil.e(TAG, "data:"+data);
if (TextUtils.equals("ZongMuService", data)) {
LogUtil.e(TAG, "receive server response");
mProtoPackage.setPackageBuffer(recvData);
mProtoPackage.parsePackage();

if(mRecvLength != mProtoPackage.getPackageSize()){
LogUtil.e(TAG,"data length parse Error");
recvData = null;
mRecvLength = -1;
return -3;
}

byte[] serviceParamPackage = mProtoPackage.getParamPackage();
try {
responsePrototype = responsePrototype.getParserForType().parseFrom(serviceParamPackage);
done.run(responsePrototype);
} catch (InvalidProtocolBufferException e) {
e.printStackTrace();
}
recvData = null;
mRecvLength = -1;
LogUtil.d(TAG,"callback finish");
}else {
LogUtil.d(TAG,"receive error");
recvData = null;
mRecvLength = -1;
return Constants.RECEIVE_DATA_ERROR;
}
return Constants.RECEIVE_DATA_SUCCESS;
}

@Override
public void start() {
if(TextUtils.isEmpty(mRemoteIp)){
LogUtil.i( TAG,"remote ip is null");
return;
}
new Thread(new Runnable() {
@Override
public void run() {
try {
mSelector = Selector.open();
InetSocketAddress inetSocketAddress = new InetSocketAddress(mRemoteIp, Constants.TCP_PORT);
mSocketChannel = SocketChannel.open(inetSocketAddress);
mSocketChannel.configureBlocking(false);
mSocketChannel.register(mSelector, SelectionKey.OP_READ);
LogUtil.e(TAG, "tcp socket connect success");
mCallback.onTcpConnect(Constants.SOCKET_CONN_SUCCESS);
} catch (IOException e) {
e.printStackTrace();
LogUtil.e(TAG, "tcp socket connect failed");
mCallback.onTcpConnect(Constants.SOCKET_CONN_FAILED);
}
}
}).start();
}

@Override
public void stop() {
try {
if (mSocketChannel != null && mSocketChannel.isConnected()) {
mSocketChannel.finishConnect();
mSelector.close();
mSocketChannel.close();
LogUtil.e( TAG,"tcp socket closed");
}
} catch (IOException e) {
e.printStackTrace();
LogUtil.e( TAG,"tcp socket closed:"+e.toString());
}
}

}

Android SocketChannel使用

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