java网络
网络
TCP
TCP 快速入门(字节流)
快速实现本机 client 发送一句话给server server回一句（字节流）
注意 ： socket.shutdownOutput();//设置结束标记
Server
public class Server {public static void main(String[] args) throws IOException {ServerSocket serverSocket = new ServerSocket(9997);Socket socket = serverSocket.accept();//有客户端连接 返回socket对象 程序继续byte[] read = new byte[1024];int readLen;InputStream inputStream = socket.getInputStream();while((readLen = inputStream.read(read)) != -1){System.out.println(new String(read,0,readLen));}OutputStream outputStream = socket.getOutputStream();outputStream.write("你也好".getBytes());socket.shutdownOutput();//设置结束标记outputStream.close();inputStream.close();socket.close();serverSocket.close();}
}
Client
public class Client {public static void main(String[] args) throws IOException {Socket socket = new Socket(InetAddress.getLocalHost(),9997);OutputStream outputStream = socket.getOutputStream();outputStream.write("哈哈，你好！".getBytes());socket.shutdownOutput();byte[] read = new byte[1024];int readLen;InputStream inputStream = socket.getInputStream();while((readLen = inputStream.read(read)) != -1){System.out.println(new String(read,0,readLen));System.out.println("拜拜");}outputStream.close();inputStream.close();socket.close();}
}
TCP 快速入门(字符流)
注意：bufferedWriter.newLine(); //结束标记
bufferedWriter.flush(); //要写啊
后打开的流尽量先关闭
Server
public class Server {public static void main(String[] args) throws IOException {ServerSocket serverSocket = new ServerSocket(9997);Socket socket = serverSocket.accept();//有客户端连接 返回socket对象 程序继续String readLine;InputStream inputStream = socket.getInputStream();InputStreamReader inputStreamReader = new InputStreamReader(inputStream); //转换流BufferedReader bufferedReader = new BufferedReader(inputStreamReader);System.out.println(bufferedReader.readLine()); //别用while ,client就相当于写了一行OutputStream outputStream = socket.getOutputStream();OutputStreamWriter outputStreamWriter = new OutputStreamWriter(outputStream);BufferedWriter bufferedWriter = new BufferedWriter(outputStreamWriter);bufferedWriter.write("你也好啊！");bufferedWriter.newLine(); //结束标记bufferedWriter.flush(); //要写啊bufferedWriter.close();bufferedReader.close();socket.close();serverSocket.close();}
}
Client
public class Client {public static void main(String[] args) throws IOException {Socket socket = new Socket(InetAddress.getLocalHost(),9997);OutputStream outputStream = socket.getOutputStream();OutputStreamWriter outputStreamWriter = new OutputStreamWriter(outputStream);BufferedWriter bufferedWriter = new BufferedWriter(outputStreamWriter);bufferedWriter.write("哈哈，你好！");bufferedWriter.newLine(); //结束标记bufferedWriter.flush(); //String readLine;InputStream inputStream = socket.getInputStream();InputStreamReader inputStreamReader = new InputStreamReader(inputStream); //转换流BufferedReader bufferedReader = new BufferedReader(inputStreamReader);System.out.println(bufferedReader.readLine());System.out.println("拜拜");bufferedReader.close();bufferedWriter.close();socket.close();}
}
TCP快速入门（client上传个图片01）
client发送图片给server ，server收到后回复一句话.
这里采用边读边发的模式
server用的是包装字节流 ，想着像下面这么用
OutputStream outputStream = socket.getOutputStream();
outputStream.write(“你也好”.getBytes());
socket.shutdownOutput();//设置结束标记
outputStream.close(); 用 bufferedOutputStream.write(“收到了”.getBytes()); 直接关闭，加上shutdown会报错 具体后续研究
Server
public class Server {public static void main(String[] args) throws IOException {ServerSocket serverSocket = new ServerSocket(9997);Socket socket = serverSocket.accept();//有客户端连接 返回socket对象 程序继续int readLine;byte[] read = new byte[102400];InputStream inputStream = socket.getInputStream();BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream);BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(new FileOutputStream("src\\胡歌.jpeg"));while((readLine =bufferedInputStream.read(read))!=-1){bufferedOutputStream.write(read,0,readLine);}bufferedOutputStream = new BufferedOutputStream(socket.getOutputStream());bufferedOutputStream.write("收到了".getBytes());// socket.shutdownOutput();//Cannot send after socket shutdown: socket write errorbufferedOutputStream.close();
// socket.shutdownOutput();//Socket is closedbufferedInputStream.close();socket.close();serverSocket.close();}
}
Client
public class Client {public static void main(String[] args) throws IOException {Socket socket = new Socket(InetAddress.getLocalHost(),9997);String path = "d:\\胡歌.jpeg";OutputStream outputStream = socket.getOutputStream();//client 发送BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(outputStream);int redLine ;byte[] read = new byte[120400];BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(path)); //读取磁盘文件的输入包装流while((redLine = bufferedInputStream.read(read)) != -1){bufferedOutputStream.write(read,0,redLine);System.out.println("bufferedOutputStream.write :" + redLine);}socket.shutdownOutput();//bufferedInputStream = new BufferedInputStream(socket.getInputStream());while((redLine = bufferedInputStream.read(read)) != -1){System.out.println(new String(read,0,redLine));}bufferedOutputStream.close();bufferedInputStream.close();socket.close();}
}TCP快速入门（client上传个图片02）
Server
public class Server {public static void main(String[] args) throws Exception {ServerSocket serverSocket = new ServerSocket(9996);Socket socket = serverSocket.accept();//有客户端连接 返回socket对象 程序继续BufferedInputStream bufferedInputStream = new BufferedInputStream(socket.getInputStream());byte[] bytes = StreamUtils.streamToByteArray(bufferedInputStream);BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(new FileOutputStream("src\\1.jpeg"));bufferedOutputStream.write(bytes);bufferedOutputStream.close();BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));bufferedWriter.write("收到了");bufferedWriter.flush();socket.shutdownOutput();bufferedWriter.close();bufferedInputStream.close();socket.close();serverSocket.close();}
}Client
public class Client {public static void main(String[] args) throws Exception {Socket socket = new Socket(InetAddress.getLocalHost(),9996);String path = "d:\\1.jpg";BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(path)); //读取磁盘文件的输入包装流byte[] bytes = StreamUtils.streamToByteArray(bufferedInputStream);BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(socket.getOutputStream());bufferedOutputStream.write(bytes);InputStream inputStream = socket.getInputStream();System.out.println(StreamUtils.streamToString(inputStream));inputStream.close();bufferedInputStream.close();socket.shutdownOutput();bufferedOutputStream.close();socket.close();}
}
StreamUtils
public class StreamUtils {/*** 功能：将输入流转换成byte[]， 即可以把文件的内容读入到byte[]* @param is* @return* @throws Exception*/public static byte[] streamToByteArray(InputStream is) throws Exception{ByteArrayOutputStream bos = new ByteArrayOutputStream();//创建输出流对象byte[] b = new byte[1024];//字节数组int len;while((len=is.read(b))!=-1){//循环读取bos.write(b, 0, len);//把读取到的数据，写入bos }byte[] array = bos.toByteArray();//然后将bos 转成字节数组bos.close();return array;}/*** 功能：将InputStream转换成String* @param is* @return* @throws Exception*/public static String streamToString(InputStream is) throws Exception{BufferedReader reader = new BufferedReader(new InputStreamReader(is));StringBuilder builder= new StringBuilder();String line;while((line=reader.readLine())!=null){builder.append(line+"\r\n");}return builder.toString();}
}
TCP下载文件
client 从server下载个图片
public class Server03 {public static void main(String[] args) throws Exception {ServerSocket serverSocket = new ServerSocket(9995);Socket socket = serverSocket.accept();String path = "d:\\";String filename = StreamUtils.streamToString(socket.getInputStream());File file = new File(path + filename);System.out.println("收到 ：" +filename);String sendFileName = "胡歌.jpeg";if(file.exists()){sendFileName = filename;}//读取服务器文件BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(path + sendFileName));byte[] bytes = StreamUtils.streamToByteArray(bufferedInputStream); //图片System.out.println(bytes.length);BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(socket.getOutputStream());bufferedOutputStream.write(bytes);bufferedOutputStream.flush();socket.shutdownOutput();bufferedInputStream.close();socket.close();serverSocket.close();}}public class Client03 {public static void main(String[] args) throws Exception {Socket socket = new Socket(InetAddress.getLocalHost(), 9995);System.out.println("请输入你想要的图片:");Scanner scanner = new Scanner(System.in);String filename = scanner.next();BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));bufferedWriter.write(filename);bufferedWriter.newLine();bufferedWriter.close();
// OutputStream outputStream = socket.getOutputStream();
// outputStream.write(filename.getBytes());
// socket.shutdownOutput();
// outputStream.close();BufferedInputStream bufferedInputStream = new BufferedInputStream(socket.getInputStream());byte[] bytes = StreamUtils.streamToByteArray(bufferedInputStream);BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(new FileOutputStream("src\\" + filename));bufferedOutputStream.write(bytes);bufferedOutputStream.close();bufferedInputStream.close();socket.close();}
}TCP细节
当客户端来连接到服务端后，实际上客户端也是通过一个端口和服务端进行通讯的，这个端口是TCP/IP来分配的，是不确定的随机的。
UDP
基本流程
1.核心类 DatagramSocket 与DatagramPacket
2.建立发送 接收端
3.发送数据前，建立数据报/DatagramPacket
4.用DatagramSocket发送接收方法
5.关闭DatagramSocket
UDP使用
收发消息一次
UDPReceiver
public class UDPReceiver {public static void main(String[] args) throws Exception{//创建DatagramSocket准备接受数据DatagramSocket datagramSocket = new DatagramSocket(9990);//创建DatagramPacket对象准备接受数据 UDP最大数据64Kbyte[] bytes = new byte[64*1024];//调用接受方法 DatagramPacket对象填充到datagramPacketDatagramPacket datagramPacket = new DatagramPacket(bytes, bytes.length);datagramSocket.receive(datagramPacket);//有数据包发送到本机端口 会接收到数据，没有数据过来会阻塞// datagramPacket拆包int length = datagramPacket.getLength();byte[] data = datagramPacket.getData();System.out.println(new String(data,0,length));byte[] bytes1 = "来者犹可追！".getBytes();datagramPacket = new DatagramPacket(bytes1, bytes1.length, InetAddress.getLocalHost(), 9991);datagramSocket.send(datagramPacket);//关闭socketdatagramSocket.close();}
}
UDPSender
public class UDPSender {public static void main(String[] args) throws Exception{DatagramSocket datagramSocket = new DatagramSocket(9991);byte[] bytes = "往者不可谏".getBytes();//更多时候用 InetAddress.getAllByName("ip")DatagramPacket datagramPacket = new DatagramPacket(bytes, bytes.length, InetAddress.getLocalHost(), 9990);datagramSocket.send(datagramPacket);byte[] bytes1 = new byte[64*1024];//调用接受方法 DatagramPacket对象填充到datagramPacketdatagramPacket = new DatagramPacket(bytes1, bytes1.length);datagramSocket.receive(datagramPacket);//有数据包发送到本机端口 会接收到数据，没有数据过来会阻塞// datagramPacket拆包int length = datagramPacket.getLength();byte[] data = datagramPacket.getData();System.out.println(new String(data,0,length));datagramSocket.close();}
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