TCP通信
概念
传输控制协议（TCP，Transmission Control Protocol）是一种面向连接的、可靠的、基于字节流的传输层通信协议。
从百科定义中就可以看出，TCP通信的基本条件是连接，传输的是字节流。
- 通信基本流程（类似打招呼的方式）：
1.三次握手
2.四次挥手
客户端
//客户端
public class TCPDemo01 {
public static void main(String[] args) throws Exception {
//1.要知道服务器的ip，端口号
InetAddress ip = InetAddress.getByName("127.0.0.1");//ip
int port = 9999;//端口号
//创建socket
Socket socket = new Socket(ip,port);
//发送消息
OutputStream os = socket.getOutputStream();
os.write("你好".getBytes());
//关闭资源
os.close();
socket.close();
}
}
服务端
//服务端
public class TCPDemo02 {
public static void main(String[] args) throws Exception {
//1.有一个端口号
ServerSocket serverSocket = new ServerSocket(9999);
//2.等待客户端连接
Socket socket = serverSocket.accept();//客户端的socket
//3.读取客户端消息
InputStream is = socket.getInputStream();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
int len;
while ((len=is.read(buf))!=-1){
baos.write(buf,0,len);
}
System.out.println(baos.toString());
//关闭资源
baos.close();
is.close();
socket.close();
serverSocket.close();
}
}
- 用TCP协议实现上传文件到服务端
客户端
public class client01 {
public static void main(String[] args) throws Exception {
//1.获取服务端ip和端口
InetAddress ip = InetAddress.getByName("127.0.0.1");
int port = 9999;
//2.创建socket对象
Socket socket = new Socket(ip,port);
//3.获取输出流
OutputStream os = socket.getOutputStream();
//4.创建文件输入流
FileInputStream fis = new FileInputStream("F:/桌面文件/a.txt");
//5.写文件
byte[] buf = new byte[1024];//缓冲区
int len;
while ((len=fis.read(buf))!=-1){
os.write(buf,0,len);
}
//通知传输结束
socket.shutdownOutput();//输出完了
//等服务端接收完
InputStream is = socket.getInputStream();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buf2 = new byte[1024];
int len2;
while ((len2=is.read(buf2))!=-1){
baos.write(buf2,0,len2);
}
System.out.println(baos.toString());
//6.关闭资源
baos.close();
is.close();
fis.close();
os.close();
socket.close();
}
}
服务端
public class servlet01 {
public static void main(String[] args) throws IOException {
//1.创建服务端接口
ServerSocket serverSocket = new ServerSocket(9999);
//2.等待连接
Socket socket = serverSocket.accept();
//3.输入流
InputStream is = socket.getInputStream();
//4.创建文件输出流
FileOutputStream fos = new FileOutputStream("receive.txt");
//5.输出文件
byte[] buf = new byte[1024];
int len;
while ((len=is.read(buf))!=-1){
fos.write(buf,0,len);
}
//通知客户端，接收完毕
OutputStream os = socket.getOutputStream();
os.write("接受完毕".getBytes());
//6.关闭资源
fos.close();
is.close();
socket.close();
serverSocket.close();
}
}