网络编程java
一.TCP的简单使用（可信但效率低）
①自定义客户端与服务器，进行图片的复制
客户端
public void client() { OutputStream os = null; FileInputStream file1 = null; InputStream is = null; ByteArrayOutputStream bo = null; try { //ip地址 Socket socket = new Socket(InetAddress.getByName("127.0.0.1"),9090); os = socket.getOutputStream(); file1 = new FileInputStream(new File("OIP1-C.jpg")); //读取图片的信息 byte[] buffer = new byte[100]; int lent; while ((lent = file1.read(buffer)) != -1) { os.write(buffer,0,lent); } //告诉服务器传输的数据结束 socket.shutdownInput(); //读入来自服务器的数据 is = socket.getInputStream(); bo = new ByteArrayOutputStream(); byte[] arr = new byte[100]; int len; while ((len = is.read(arr) ) != -1) { bo.write(arr,0,len); } System.out.println(bo.toString()); } catch (IOException e) { e.printStackTrace(); } finally { //流的关闭 if (os != null) { try { os.close(); } catch (IOException e) { e.printStackTrace(); } } if (file1 != null) { try { file1.close(); } catch (IOException e) { e.printStackTrace(); } } if (is != null) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } if (bo != null) { try { bo.close(); } catch (IOException e) { e.printStackTrace(); } } } }服务器
public void server() { ServerSocket ss = null; Socket accept = null; InputStream is = null; FileOutputStream file2 = null; OutputStream outputStream = null; try { //自己的端口值 ss = new ServerSocket(9090); accept = ss.accept(); is = accept.getInputStream(); file2 = new FileOutputStream("`OIP12-C.jpg"); //复制图片的操作 byte[] buffer = new byte[100]; int lent; while ((lent = is.read()) != -1) { file2.write(buffer,0,lent); } //传给客户端的信息 outputStream = accept.getOutputStream(); outputStream.write("已收到".getBytes(StandardCharsets.UTF_8)); } catch (IOException e) { e.printStackTrace(); } finally { while (ss != null) { try { ss.close(); } catch (IOException e) { e.printStackTrace(); } } while (accept != null) { try { accept.close(); } catch (IOException e) { e.printStackTrace(); } } while (is != null) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } while (file2 != null) { try { file2.close(); } catch (IOException e) { e.printStackTrace(); } } while (outputStream != null) { try { outputStream.close(); } catch (IOException e) { e.printStackTrace(); } } } }②使用浏览器与Tomcat服务器的连接
首先需要配置tomcat，在控制台输入catalina run后在浏览器输入 http://localhost:8080
可随意在一个地方创建一个txt，然后在浏览器输入http://localhost:8080/1/hello.txt(举例)
便可在网页看到自己在文本输入的内容了
2.UDP（不可信但效率高）
发送
public void sender() { DatagramSocket socket = null; try { socket = new DatagramSocket(); String arr = "我传输了信息过来"; byte[] data = arr.getBytes(StandardCharsets.UTF_8); InetAddress ient = InetAddress.getLocalHost(); DatagramPacket packet = new DatagramPacket(data,0,data.length,ient,8080); //将信息打包并发送出去 socket.send(packet); } catch (IOException e) { e.printStackTrace(); } finally { if(socket != null) socket.close(); } }接收
public void reader() throws Exception { //服务器的端口 DatagramSocket data = new DatagramSocket(8080); byte[] bytes = new byte[100]; DatagramPacket packet = new DatagramPacket(bytes,0,bytes.length); data.receive(packet); System.out.println(new String(packet.getData(),0,packet.getLength())); }③URL(较为常用)实现tomcat服务端数据下载
public static void main(String[] args) { HttpURLConnection urlConnection = null; InputStream inputStream = null; FileOutputStream fileOutputStream = null; try { URL url = new URL("http://localhost:8080/1/bea.jpg"); urlConnection = (HttpURLConnection) url.openConnection(); urlConnection.connect(); inputStream = urlConnection.getInputStream(); fileOutputStream = new FileOutputStream("bea1,jpg"); byte[] bytes = new byte[1000]; int len; while ((len = inputStream.read()) != -1) { fileOutputStream.write(bytes,0,len); } } catch (IOException e) { e.printStackTrace(); } finally { if (inputStream != null) { try { inputStream.close(); } catch (IOException e) { e.printStackTrace(); } } if (fileOutputStream != null) { try { fileOutputStream.close(); } catch (IOException e) { e.printStackTrace(); } } if (urlConnection != null) urlConnection.disconnect(); }}