TCP/IP参考模型
TCP/IP参考模型是首先由ARPANET所使用的网络体系结构。这个体系结构在它的两个主要协议出现以后被称为TCP/IP参考模型(TCP/IP Reference Model)。这一网络协议共分为四层:网络访问层、互联网层、传输层和应用层。如下图:
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TCP简介
TCP(Transmission Control Protocol 传输控制协议)是一种面向连接的、可靠的、基于字节流的传输层通信协议,由IETF的RFC 793定义。在简化的计算机网络OSI模型中,它完成第四层传输层所指定的功能,用户数据报协议(UDP)是同一层内 另一个重要的传输协议。在因特网协议族(Internet protocol suite)中,TCP层是位于IP层之上,应用层之下的中间层。不同主机的应用层之间经常需要可靠的、像管道一样的连接,但是IP层不提供这样的流机制,而是提供不可靠的包交换。
基于Socket的TCP编程
TCP通信中包含服务端和客户端,下面分别讲述。
服务端
第一步 创建ServerSocket实例;
第二步 调用ServerSocket的accept()方法,等待客户端连接;
第三步 客户端连接上服务端之后,数据读写。
下面贴上示例代码:
public class Server extends Base {
private ServerSocket mServerSocket;
private Socket mSocket;
public Server(BaseListener listener) {
super(listener);
}
public void start() {
new Thread(new Runnable() {
@Override
public void run() {
try {
mServerSocket = new ServerSocket(8090);
mSocket = mServerSocket.accept();
mHandler.sendMsgConnected();
recv();
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
}
public void stop() {
if (mServerSocket != null) {
try {
mServerSocket.close();
mServerSocket = null;
mHandler.sendMsgDisconnected();
} catch (IOException e) {
e.printStackTrace();
}
}
}
private void recv() {
if (mSocket == null) {
return;
}
try {
InputStream is = mSocket.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
int i = 0;
String content;
while ((content = reader.readLine()) != null) {
mHandler.sendMsgRecv(content);
send("hello world:" + (i++));
}
} catch (IOException e) {
e.printStackTrace();
}
}
public boolean send(@NonNull String content) {
if (mSocket == null || !mSocket.isConnected()) {
return false;
}
try {
OutputStream os = mSocket.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os));
writer.write(content + "\n");
writer.flush();
} catch (IOException e) {
e.printStackTrace();
return false;
}
return true;
}
}
客户端
第一步 创建Socket实例;
第二步 连接上服务端之后,读写数据。
下面贴上示例代码:
public class Client extends Base {
private Socket mSocket;
public Client(BaseListener listener) {
super(listener);
}
public void start() {
new Thread(new Runnable() {
@Override
public void run() {
if (mSocket != null) {
try {
mSocket.close();
mHandler.sendMsgDisconnected();
} catch (IOException e) {
e.printStackTrace();
return;
}
}
try {
mSocket = new Socket("127.0.0.1", 8090);
mHandler.sendMsgConnected();
read();
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
}
public void stop() {
if (mSocket != null) {
try {
mSocket.close();
mSocket = null;
} catch (IOException e) {
e.printStackTrace();
}
}
}
private void read() {
if (mSocket == null || !mSocket.isConnected()) {
return;
}
try {
InputStream is = mSocket.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
String content;
while ((content = reader.readLine()) != null) {
mHandler.sendMsgRecv(content);
}
} catch (IOException e) {
e.printStackTrace();
}
}
public boolean send(@NonNull String content) {
if (mSocket == null || !mSocket.isConnected()) {
return false;
}
try {
OutputStream os = mSocket.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os));
writer.write(content + "\n");
writer.flush();
} catch (IOException e) {
e.printStackTrace();
return false;
}
return true;
}
}
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