网络编程与通信原理(网络编程技术与应用)

  本篇文章为你整理了网络编程与通信原理(网络编程技术与应用)的详细内容,包含有网络编程与应用 网络编程技术与应用 网络编程与计算技术 网络通信程序设计课程 网络编程与通信原理,希望能帮助你了解 网络编程与通信原理。

   应用层:HTTP超文本传输协议,基于TCP/IP通信协议来传递数据;传输层:TCP传输控制协议,采用三次握手的方式建立连接,形成数据传输通道;网络层:IP协议,作用是把各种传输的数据包发送给请求的接收方;

  
 

  目录一、基础概念二、JDK源码1、InetAddress2、URL3、HttpURLConnection三、通信编程1、Socket2、SocketServer3、SocketClient4、字符流使用5、文件传输6、TCP协议四、Http组件1、基础接口2、ApacheHttp3、OkHttp4、RestTemplate五、参考源码

  总感觉这个概念,和研发有点脱节;

  一、基础概念

  不同设备之间通过网络进行数据传输,并且基于通用的网络协议作为多种设备的兼容标准,称为网络通信;

  以C/S架构来看,在一次请求当中,客户端和服务端进行数据传输的交互时,在不同阶段和层次中需要遵守的网络通信协议也不一样;

  应用层:HTTP超文本传输协议,基于TCP/IP通信协议来传递数据;

  传输层:TCP传输控制协议,采用三次握手的方式建立连接,形成数据传输通道;

  网络层:IP协议,作用是把各种传输的数据包发送给请求的接收方;

  通信双方进行交互时,发送方数据在各层传输时,每通过一层就会添加该层的首部信息;接收方与之相反,每通过一次就会删除该层的首部信息;

  二、JDK源码

  在java.net源码包中,提供了与网络编程相关的基础API;

  1、InetAddress

  封装了对IP地址的相关操作,在使用该API之前可以先查看本机的hosts的映射,Linux系统中在/etc/hosts路径下;

  

import java.net.InetAddress;

 

  public class TestInet {

   public static void main(String[] args) throws Exception {

   // 获取本机 InetAddress 对象

   InetAddress localHost = InetAddress.getLocalHost();

   printInetAddress(localHost);

   // 获取指定域名 InetAddress 对象

   InetAddress inetAddress = InetAddress.getByName("www.baidu.com");

   printInetAddress(inetAddress);

   // 获取本机配置 InetAddress 对象

   InetAddress confAddress = InetAddress.getByName("nacos-service");

   printInetAddress(confAddress);

   public static void printInetAddress (InetAddress inetAddress){

   System.out.println("InetAddress:"+inetAddress);

   System.out.println("主机名:"+inetAddress.getHostName());

   System.out.println("IP地址:"+inetAddress.getHostAddress());

  

 

  2、URL

  统一资源定位符,URL一般包括:协议、主机名、端口、路径、查询参数、锚点等,路径+查询参数,也被称为文件;

  

import java.net.URL;

 

  public class TestURL {

   public static void main(String[] args) throws Exception {

   URL url = new URL("https://www.baidu.com:80/s?wd=Java#bd") ;

   printURL(url);

   private static void printURL (URL url){

   System.out.println("协议:" + url.getProtocol());

   System.out.println("域名:" + url.getHost());

   System.out.println("端口:" + url.getPort());

   System.out.println("路径:" + url.getPath());

   System.out.println("参数:" + url.getQuery());

   System.out.println("文件:" + url.getFile());

   System.out.println("锚点:" + url.getRef());

  

 

  3、HttpURLConnection

  作为URLConnection的抽象子类,用来处理针对Http协议的请求,可以设置连接超时、读取超时、以及请求的其他属性,是服务间通信的常用方式;

  

public class TestHttp {

 

   public static void main(String[] args) throws Exception {

   // 访问 网址 内容

   URL url = new URL("https://www.jd.com");

   HttpURLConnection httpUrlConnection = (HttpURLConnection) url.openConnection();

   printHttp(httpUrlConnection);

   // 请求 服务 接口

   URL api = new URL("http://localhost:8082/info/99");

   HttpURLConnection apiConnection = (HttpURLConnection) api.openConnection();

   apiConnection.setRequestMethod("GET");

   apiConnection.setConnectTimeout(3000);

   printHttp(apiConnection);

   private static void printHttp (HttpURLConnection httpUrlConnection) throws Exception{

   try (InputStream inputStream = httpUrlConnection.getInputStream()) {

   BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));

   String line ;

   while ((line = bufferedReader.readLine()) != null) {

   System.out.println(line);

  

 

  三、通信编程

  1、Socket

  Socket也被称为套接字,是两台设备之间通信的端点,会把网络连接当成流处理,则数据以IO形式传输,这种方式在当前被普遍采用;

  从网络编程直接跳到Socket套接字,概念上确实有较大跨度,概念过度抽象时,可以看看源码的核心结构,在理解时会轻松很多,在JDK中重点看SocketImpl抽象类;

  

public abstract class SocketImpl implements SocketOptions {

 

   // Socket对象,客户端和服务端

   Socket socket = null;

   ServerSocket serverSocket = null;

   // 套接字的文件描述对象

   protected FileDescriptor fd;

   // 套接字的路由IP地址

   protected InetAddress address;

   // 套接字连接到的远程主机上的端口号

   protected int port;

   // 套接字连接到的本地端口号

   protected int localport;

  

 

  套接字的抽象实现类,是实现套接字的所有类的公共超类,可以用于创建客户端和服务器套接字;

  所以到底如何理解Socket概念?从抽象类中来看,套接字就是指代网络通讯中系统资源的核心标识,比如通讯方IP地址、端口、状态等;

  2、SocketServer

  创建Socket服务端,并且在8989端口监听,接收客户端的连接请求和相关信息,并且响应客户端,发送指定的数据;

  

public class SocketServer {

 

   public static void main(String[] args) throws Exception {

   // 1、创建Socket服务端

   ServerSocket serverSocket = new ServerSocket(8989);

   System.out.println("socket-server:8989,waiting connect...");

   // 2、方法阻塞等待,直到有客户端连接

   Socket socket = serverSocket.accept();

   System.out.println("socket-server:8989,get connect:"+socket.getPort());

   // 3、输入流,输出流

   InputStream inStream = socket.getInputStream();

   OutputStream outStream = socket.getOutputStream();

   // 4、数据接收和响应

   byte[] buf = new byte[1024];

   int readLen = 0;

   while ((readLen=inStream.read(buf)) != -1){

   // 接收数据

   String readVar = new String(buf, 0, readLen) ;

   if ("exit".equals(readVar)){

   break ;

   System.out.println("recv:"+readVar+";time:"+DateTime.now().toString(DatePattern.NORM_DATETIME_PATTERN));

   // 响应数据

   outStream.write(("resp-time:"+DateTime.now().toString(DatePattern.NORM_DATETIME_PATTERN)).getBytes());

   // 5、资源关闭

   outStream.close();

   inStream.close();

   socket.close();

   serverSocket.close();

   System.out.println("socket-server:8989,exit...");

  

 

  需要注意的是步骤2输出的端口号是随机不确定的,结合jps和lsof -i tcp:port命令查看进程和端口号的占用情况;

  3、SocketClient

  创建Socket客户端,并且连接到服务端,读取命令行输入的内容并发送到服务端,并且输出服务端的响应数据;

  

public class SocketClient {

 

   public static void main(String[] args) throws Exception {

   // 1、创建Socket客户端

   Socket socket = new Socket(InetAddress.getLocalHost(), 8989);

   System.out.println("server-client,connect to:8989");

   // 2、输入流,输出流

   OutputStream outStream = socket.getOutputStream();

   InputStream inStream = socket.getInputStream();

   // 3、数据发送和响应接收

   int readLen = 0;

   byte[] buf = new byte[1024];

   while (true){

   // 读取命令行输入

   BufferedReader bufReader = new BufferedReader(new InputStreamReader(System.in));

   String iptLine = bufReader.readLine();

   if ("exit".equals(iptLine)){

   break;

   // 发送数据

   outStream.write(iptLine.getBytes());

   // 接收数据

   if ((readLen = inStream.read(buf)) != -1) {

   System.out.println(new String(buf, 0, readLen));

   // 4、资源关闭

   inStream.close();

   outStream.close();

   socket.close();

   System.out.println("socket-client,get exit command");

  

 

  测试结果:整个流程在没有收到客户端的exit退出指令前,会保持连接的状态,并且可以基于字节流模式,进行持续的数据传输;

  4、字符流使用

  基于上述的基础案例,采用字符流的方式进行数据传输,客户端和服务端只进行一次简单的交互;

  

-- 1、客户端

 

  BufferedReader bufReader = new BufferedReader(new InputStreamReader(inStream));

  BufferedWriter bufWriter = new BufferedWriter(new OutputStreamWriter(outStream));

  // 客户端发送数据

  bufWriter.write("hello,server");

  bufWriter.newLine();

  bufWriter.flush();

  // 客户端接收数据

  System.out.println("client-read:"+bufReader.readLine());

  -- 2、服务端

  BufferedReader bufReader = new BufferedReader(new InputStreamReader(inStream));

  BufferedWriter bufWriter = new BufferedWriter(new OutputStreamWriter(outStream));

  // 服务端接收数据

  System.out.println("server-read:"+bufReader.readLine());

  // 服务端响应数据

  bufWriter.write("hello,client");

  bufWriter.newLine();

  bufWriter.flush();

  

 

  5、文件传输

  基于上述的基础案例,客户端向服务端发送图片文件,服务端完成文件的读取和保存,在处理完成后给客户端发送结果描述;

  

-- 1、客户端

 

  // 客户端发送图片

  FileInputStream fileStream = new FileInputStream("Local_File_Path/jvm.png");

  byte[] bytes = new byte[1024];

  int i = 0;

  while ((i = fileStream.read(bytes)) != -1) {

   outStream.write(bytes);

  // 写入结束标记,禁用此套接字的输出流,之后再使用输出流会抛异常

  socket.shutdownOutput();

  // 接收服务端响应结果

  System.out.println("server-resp:"+new String(bytes,0,readLen));

  -- 2、服务端

  // 接收客户端图片

  FileOutputStream fileOutputStream = new FileOutputStream("Local_File_Path/new_jvm.png");

  byte[] bytes = new byte[1024];

  int i = 0;

  while ((i = inStream.read(bytes)) != -1) {

   fileOutputStream.write(bytes, 0, i);

  // 响应客户端文件处理结果

  outStream.write("file-save-success".getBytes());

  

 

  6、TCP协议

  Socket网络编程是基于TCP协议的,TCP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,在上述案例中侧重基于流的数据传输,其中关于连接还涉及两个核心概念:

  三次握手:建立连接的过程,在这个过程中进行了三次网络通信,当连接处于建立的状态,就可以进行正常的通信,即数据传输;四次挥手:关闭连接的过程,调用close方法,即连接使用结束,在这个过程中进行了四次网络通信;

  四、Http组件

  在服务通信时依赖网络,而对于编程来说,更常见的是的Http的组件,在微服务架构中,涉及到Http组件工具有很多,例如Spring框架中的RestTemplate,Feign框架支持ApacheHttp和OkHttp;下面围绕几个常用的组件编写测试案例;

  1、基础接口

  

@RestController

 

  public class BizWeb {

   @GetMapping("/getApi/{id}")

   public Rep Integer getApi(@PathVariable Integer id){

   log.info("id={}",id);

   return Rep.ok(id) ;

   @GetMapping("/getApi_v2/{id}")

   public Rep Integer getApiV2(HttpServletRequest request,

   @PathVariable Integer id,

   @RequestParam("name") String name){

   String token = request.getHeader("Token");

   log.info("token={},id={},name={}",token,id,name);

   return Rep.ok(id) ;

   @PostMapping("/postApi")

   public Rep IdKey postApi(HttpServletRequest request,@RequestBody IdKey idKey){

   String token = request.getHeader("Token");

   log.info("token={},idKey={}", token,JSONUtil.toJsonStr(idKey));

   return Rep.ok(idKey) ;

   @PutMapping("/putApi")

   public Rep IdKey putApi(@RequestBody IdKey idKey){

   log.info("idKey={}", JSONUtil.toJsonStr(idKey));

   return Rep.ok(idKey) ;

   @DeleteMapping("/delApi/{id}")

   public Rep Integer delApi(@PathVariable Integer id){

   log.info("id={}",id);

   return Rep.ok(id) ;

  

 

  2、ApacheHttp

  

public class TestApacheHttp {

 

   private static final String BASE_URL = "http://localhost:8083" ;

   public static void main(String[] args) {

   BasicHeader header = new BasicHeader("Token","ApacheSup") ;

   // 1、发送Get请求

   Map String,String param = new HashMap () ;

   param.put("name","cicada") ;

   Rep getRep = doGet(BASE_URL+"/getApi_v2/3",header,param, Rep.class);

   System.out.println("get:"+getRep);

   // 2、发送Post请求

   IdKey postBody = new IdKey(1,"id-key-我") ;

   Rep postRep = doPost (BASE_URL+"/postApi", header, postBody, Rep.class);

   System.out.println("post:"+postRep);

   * 构建HttpClient对象

   private static CloseableHttpClient buildHttpClient (){

   // 请求配置

   RequestConfig reqConfig = RequestConfig.custom().setConnectTimeout(6000).build();

   return HttpClients.custom()

   .setDefaultRequestConfig(reqConfig).build();

   * 执行Get请求

   public static T T doGet (String url, Header header, Map String,String param,

   Class T repClass) {

   // 创建Get请求

   CloseableHttpClient httpClient = buildHttpClient();

   HttpGet httpGet = new HttpGet();

   httpGet.addHeader(header);

   try {

   URIBuilder builder = new URIBuilder(url);

   if (param != null) {

   for (String key : param.keySet()) {

   builder.addParameter(key, param.get(key));

   httpGet.setURI(builder.build());

   // 请求执行

   HttpResponse httpResponse = httpClient.execute(httpGet);

   if (httpResponse.getStatusLine().getStatusCode() == 200) {

   // 结果转换

   String resp = EntityUtils.toString(httpResponse.getEntity());

   return JSONUtil.toBean(resp, repClass);

   } catch (Exception e) {

   e.printStackTrace();

   } finally {

   IoUtil.close(httpClient);

   return null;

   * 执行Post请求

   public static T T doPost (String url, Header header, Object body,Class T repClass) {

   // 创建Post请求

   CloseableHttpClient httpClient = buildHttpClient();

   HttpPost httpPost = new HttpPost(url);

   httpPost.addHeader(header);

   StringEntity conBody = new StringEntity(JSONUtil.toJsonStr(body),ContentType.APPLICATION_JSON);

   httpPost.setEntity(conBody);

   try {

   // 请求执行

   HttpResponse httpResponse = httpClient.execute(httpPost);

   if (httpResponse.getStatusLine().getStatusCode() == 200) {

   // 结果转换

   String resp = EntityUtils.toString(httpResponse.getEntity());

   return JSONUtil.toBean(resp, repClass);

   } catch (Exception e) {

   e.printStackTrace();

   }finally {

   IoUtil.close(httpClient);

   return null;

  

 

  3、OkHttp

  

public class TestOkHttp {

 

   private static final String BASE_URL = "http://localhost:8083" ;

   public static void main(String[] args) {

   Headers headers = new Headers.Builder().add("Token","OkHttpSup").build() ;

   // 1、发送Get请求

   Rep getRep = execute(BASE_URL+"/getApi/1", Method.GET.name(), headers, null, Rep.class);

   System.out.println("get:"+getRep);

   // 2、发送Post请求

   IdKey postBody = new IdKey(1,"id-key") ;

   Rep postRep = execute(BASE_URL+"/postApi", Method.POST.name(), headers, buildBody(postBody), Rep.class);

   System.out.println("post:"+postRep);

   // 3、发送Put请求

   IdKey putBody = new IdKey(2,"key-id") ;

   Rep putRep = execute(BASE_URL+"/putApi", Method.PUT.name(), headers, buildBody(putBody), Rep.class);

   System.out.println("put:"+putRep);

   // 4、发送Delete请求

   Rep delRep = execute(BASE_URL+"/delApi/2", Method.DELETE.name(), headers, null, Rep.class);

   System.out.println("del:"+delRep);

   * 构建JSON请求体

   public static RequestBody buildBody (Object body){

   MediaType mediaType = MediaType.parse("application/json; charset=utf-8");

   return RequestBody.create(mediaType, JSONUtil.toJsonStr(body)) ;

   * 构建OkHttpClient对象

   public static OkHttpClient buildOkHttp () {

   return new OkHttpClient.Builder()

   .readTimeout(10, TimeUnit.SECONDS).connectTimeout(6, TimeUnit.SECONDS)

   .connectionPool(new ConnectionPool(15, 5, TimeUnit.SECONDS))

   .build();

   * 执行请求

   public static T T execute (String url, String method,

   Headers headers, RequestBody body,

   Class T repClass) {

   // 请求创建

   OkHttpClient httpClient = buildOkHttp() ;

   Request.Builder requestBuild = new Request.Builder()

   .url(url).method(method, body);

   if (headers != null) {

   requestBuild.headers(headers);

   try {

   // 请求执行

   Response response = httpClient.newCall(requestBuild.build()).execute();

   // 结果转换

   InputStream inStream = null;

   if (response.isSuccessful()) {

   ResponseBody responseBody = response.body();

   if (responseBody != null) {

   inStream = responseBody.byteStream();

   if (inStream != null) {

   try {

   byte[] respByte = IoUtil.readBytes(inStream);

   if (respByte != null) {

   return JSONUtil.toBean(new String(respByte, Charset.defaultCharset()), repClass);

   } catch (Exception e) {

   e.printStackTrace();

   } finally {

   IoUtil.close(inStream);

   } catch (Exception e) {

   e.printStackTrace();

   return null;

  

 

  4、RestTemplate

  

public class TestRestTemplate {

 

   private static final String BASE_URL = "http://localhost:8083" ;

   public static void main(String[] args) {

   RestTemplate restTemplate = buildRestTemplate() ;

   // 1、发送Get请求

   Map String,String paramMap = new HashMap () ;

   Rep getRep = restTemplate.getForObject(BASE_URL+"/getApi/1",Rep.class,paramMap);

   System.out.println("get:"+getRep);

   // 2、发送Post请求

   IdKey idKey = new IdKey(1,"id-key") ;

   Rep postRep = restTemplate.postForObject(BASE_URL+"/postApi",idKey,Rep.class);

   System.out.println("post:"+postRep);

   // 3、发送Put请求

   IdKey idKey2 = new IdKey(2,"key-id") ;

   restTemplate.put(BASE_URL+"/putApi",idKey2,paramMap);

   // 4、发送Delete请求

   restTemplate.delete(BASE_URL+"/delApi/2",paramMap);

   // 5、自定义Header请求

   HttpHeaders headers = new HttpHeaders();

   headers.add("Token","AdminSup");

   HttpEntity IdKey requestEntity = new HttpEntity (idKey, headers);

   ResponseEntity Rep respEntity = restTemplate.exchange(BASE_URL+"/postApi",

   HttpMethod.POST, requestEntity, Rep.class);

   System.out.println("post-header:"+respEntity.getBody());

   private static RestTemplate buildRestTemplate (){

   // 1、参数配置

   SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();

   factory.setReadTimeout(3000);

   factory.setConnectTimeout(6000);

   // 2、创建对象

   return new RestTemplate(factory) ;

  

 

  五、参考源码

  

编程文档:

 

  https://gitee.com/cicadasmile/butte-java-note

  应用仓库:

  https://gitee.com/cicadasmile/butte-flyer-parent

  

 

  以上就是网络编程与通信原理(网络编程技术与应用)的详细内容,想要了解更多 网络编程与通信原理的内容,请持续关注盛行IT软件开发工作室。

郑重声明:本文由网友发布,不代表盛行IT的观点,版权归原作者所有,仅为传播更多信息之目的,如有侵权请联系,我们将第一时间修改或删除,多谢。

留言与评论(共有 条评论)
   
验证码: