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使用 Java 類實(shí)現(xiàn)Http協(xié)議

更新時(shí)間：2021年09月06日 16:45:25 作者：冰河

這篇文章主要介紹了用幾個(gè)Java類簡(jiǎn)單的實(shí)現(xiàn)了Http協(xié)議相關(guān)資料,感興趣的的朋友可以參考下面具體的文章內(nèi)容

Java 實(shí)現(xiàn)Http協(xié)議

HTTP協(xié)議屬于應(yīng)用層協(xié)議，它構(gòu)建于TCP和IP協(xié)議之上，處于TCP/IP協(xié)議架構(gòu)層的頂端，所以，它不用處理下層協(xié)議間諸如丟包補(bǔ)發(fā)、握手及數(shù)據(jù)的分段及重新組裝等繁瑣的細(xì)節(jié)，使開(kāi)發(fā)人員可以專注于應(yīng)用業(yè)務(wù)。

協(xié)議是通信的規(guī)范，為了更好的理解HTTP協(xié)議，我們可以基于Java的Socket API接口，通過(guò)設(shè)計(jì)一個(gè)簡(jiǎn)單的應(yīng)用層通信協(xié)議，來(lái)簡(jiǎn)單分析下協(xié)議實(shí)現(xiàn)的過(guò)程和細(xì)節(jié)。

在我們今天的示例程序中，客戶端會(huì)向服務(wù)端發(fā)送一條命令，服務(wù)端在接收到命令后，會(huì)判斷命令是否是“HELLO”，如果是“HELLO”，則服務(wù)端返回給客戶端的響應(yīng)為“hello”，否則，服務(wù)端返回給客戶端的響應(yīng)為“bye bye”。

我們接下來(lái)用Java實(shí)現(xiàn)這個(gè)簡(jiǎn)單的應(yīng)用層通信協(xié)議，

一、協(xié)議請(qǐng)求的定義

協(xié)議的請(qǐng)求主要包括：編碼、命令和命令長(zhǎng)度三個(gè)字段。

package com.binghe.params;
/**
 * 協(xié)議請(qǐng)求的定義
 * @author binghe
 *
 */
public class Request {
 /**
  * 協(xié)議編碼
  */
 private byte encode;
 
 /**
  * 命令
  */
 private String command;
 
 /**
  * 命令長(zhǎng)度
  */
 private int commandLength;

 public Request() {
  super();
 }

 public Request(byte encode, String command, int commandLength) {
  super();
  this.encode = encode;
  this.command = command;
  this.commandLength = commandLength;
 }

 public byte getEncode() {
  return encode;
 }

 public void setEncode(byte encode) {
  this.encode = encode;
 }

 public String getCommand() {
  return command;
 }

 public void setCommand(String command) {
  this.command = command;
 }

 public int getCommandLength() {
  return commandLength;
 }

 public void setCommandLength(int commandLength) {
  this.commandLength = commandLength;
 }

 @Override
 public String toString() {
  return "Request [encode=" + encode + ", command=" + command
    + ", commandLength=" + commandLength + "]";
 }
 
}

二、響應(yīng)協(xié)議的定義

協(xié)議的響應(yīng)主要包括：編碼、響應(yīng)內(nèi)容和響應(yīng)長(zhǎng)度三個(gè)字段。

package com.binghe.params;

/**
 * 協(xié)議響應(yīng)的定義
 * @author binghe
 *
 */
public class Response {
 /**
  * 編碼
  */
 private byte encode;
 
 /**
  * 響應(yīng)內(nèi)容
  */
 private String response;
 
 /**
  * 響應(yīng)長(zhǎng)度
  */
 private int responseLength;

 public Response() {
  super();
 }

 public Response(byte encode, String response, int responseLength) {
  super();
  this.encode = encode;
  this.response = response;
  this.responseLength = responseLength;
 }

 public byte getEncode() {
  return encode;
 }

 public void setEncode(byte encode) {
  this.encode = encode;
 }

 public String getResponse() {
  return response;
 }

 public void setResponse(String response) {
  this.response = response;
 }

 public int getResponseLength() {
  return responseLength;
 }

 public void setResponseLength(int responseLength) {
  this.responseLength = responseLength;
 }

 @Override
 public String toString() {
  return "Response [encode=" + encode + ", response=" + response
    + ", responseLength=" + responseLength + "]";
 }
 
}

三、編碼常量定義

編碼常量的定義主要包括UTF-8和GBK兩種編碼。

package com.binghe.constant;

/**
 * 常量類
 * @author binghe
 *
 */
public final class Encode {
 //UTF-8編碼
 public static final byte UTF8 = 1;
 //GBK編碼
 public static final byte GBK = 2;
}

四、客戶端的實(shí)現(xiàn)

客戶端先構(gòu)造一個(gè)request請(qǐng)求，通過(guò)Socket接口將其發(fā)送到遠(yuǎn)端，并接收遠(yuǎn)端的響應(yīng)信息，并構(gòu)造成一個(gè)Response對(duì)象。

package com.binghe.protocol.client;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

import com.binghe.constant.Encode;
import com.binghe.params.Request;
import com.binghe.params.Response;
import com.binghe.utils.ProtocolUtils;

/**
 * 客戶端代碼
 * @author binghe
 *
 */
public final class Client {
 public static void main(String[] args) throws IOException{
  //請(qǐng)求
  Request request = new Request();
  request.setCommand("HELLO");
  request.setCommandLength(request.getCommand().length());
  request.setEncode(Encode.UTF8);
  
  Socket client = new Socket("127.0.0.1", 4567);
  OutputStream out = client.getOutputStream();
  
  //發(fā)送請(qǐng)求
  ProtocolUtils.writeRequest(out, request);
  
  //讀取響應(yīng)數(shù)據(jù)
  InputStream in = client.getInputStream();
  Response response = ProtocolUtils.readResponse(in);
  System.out.println("獲取的響應(yīng)結(jié)果信息為: " + response.toString());
 }
}

五、服務(wù)端的實(shí)現(xiàn)

服務(wù)端接收客戶端的請(qǐng)求，根據(jù)接收命令的不同，響應(yīng)不同的消息信息，如果是“HELLO”命令，則響應(yīng)“hello”信息，否則響應(yīng)“bye bye”信息。

package com.binghe.protocol.server;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

import com.binghe.constant.Encode;
import com.binghe.params.Request;
import com.binghe.params.Response;
import com.binghe.utils.ProtocolUtils;

/**
 * Server端代碼
 * @author binghe
 *
 */
public final class Server {
 public static void main(String[] args) throws IOException{
  ServerSocket server = new ServerSocket(4567);
  while (true) {
   Socket client = server.accept();
   //讀取請(qǐng)求數(shù)據(jù)
   InputStream input = client.getInputStream();
   Request request = ProtocolUtils.readRequest(input);
   System.out.println("收到的請(qǐng)求參數(shù)為: " + request.toString());
   OutputStream out = client.getOutputStream();
   //組裝響應(yīng)數(shù)據(jù)
   Response response = new Response();
   response.setEncode(Encode.UTF8);
   if("HELLO".equals(request.getCommand())){
    response.setResponse("hello");
   }else{
    response.setResponse("bye bye");
   }
   response.setResponseLength(response.getResponse().length());
   ProtocolUtils.writeResponse(out, response);
  }
 }
}

六、ProtocolUtils工具類的實(shí)現(xiàn)

ProtocolUtils的readRequest方法將從傳遞進(jìn)來(lái)的輸入流中讀取請(qǐng)求的encode、command和commandLength三個(gè)參數(shù)，進(jìn)行相應(yīng)的編碼轉(zhuǎn)化，構(gòu)造成Request對(duì)象返回。而writeResponse方法則是將response對(duì)象的字段根據(jù)對(duì)應(yīng)的編碼寫(xiě)入到響應(yīng)的輸出流中。

有一個(gè)細(xì)節(jié)需要重點(diǎn)注意：OutputStream中直接寫(xiě)入一個(gè)int類型，會(huì)截取其低8位，丟棄其高24位，所以，在傳遞和接收數(shù)據(jù)時(shí)，需要進(jìn)行相應(yīng)的轉(zhuǎn)化操作。

package com.binghe.utils;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import com.binghe.constant.Encode;
import com.binghe.params.Request;
import com.binghe.params.Response;

/**
 * 協(xié)議工具類
 * @author binghe
 *
 */
public final class ProtocolUtils {
 /**
  * 從輸入流中反序列化Request對(duì)象
  * @param input
  * @return
  * @throws IOException
  */
 public static Request readRequest(InputStream input) throws IOException{
  //讀取編碼
  byte[] encodeByte = new byte[1];
  input.read(encodeByte);
  byte encode = encodeByte[0];
  
  //讀取命令長(zhǎng)度
  byte[] commandLengthBytes = new byte[4];
  input.read(commandLengthBytes);
  int commandLength = ByteUtils.byte2Int(commandLengthBytes);
  
  //讀取命令
  byte[] commandBytes = new byte[commandLength];
  input.read(commandBytes);
  String command = "";
  if(Encode.UTF8 == encode){
   command = new String(commandBytes, "UTF-8");
  }else if(Encode.GBK == encode){
   command = new String(commandBytes, "GBK");
  }
  //組裝請(qǐng)求返回
  Request request = new Request(encode, command, commandLength);
  return request;
 }
 /**
  * 從輸入流中反序列化Response對(duì)象
  * @param input
  * @return
  * @throws IOException
  */
 public static Response readResponse(InputStream input) throws IOException{
  //讀取編碼
  byte[] encodeByte = new byte[1];
  input.read(encodeByte);
  byte encode = encodeByte[0];
  
  //讀取響應(yīng)長(zhǎng)度
  byte[] responseLengthBytes = new byte[4];
  input.read(responseLengthBytes);
  int responseLength = ByteUtils.byte2Int(responseLengthBytes);
  
  //讀取命令
  byte[] responseBytes = new byte[responseLength];
  input.read(responseBytes);
  String response = "";
  if(Encode.UTF8 == encode){
   response = new String(responseBytes, "UTF-8");
  }else if(Encode.GBK == encode){
   response = new String(responseBytes, "GBK");
  }
  //組裝請(qǐng)求返回
  Response resp = new Response(encode, response, responseLength);
  return resp;
 }
 
 /**
  * 序列化請(qǐng)求信息
  * @param output
  * @param response
  */
 public static void writeRequest(OutputStream output, Request request) throws IOException{
  //將response響應(yīng)返回給客戶端
  output.write(request.getEncode());
  //output.write(response.getResponseLength());直接write一個(gè)int類型會(huì)截取低8位傳輸丟棄高24位
  output.write(ByteUtils.int2ByteArray(request.getCommandLength()));
  if(Encode.UTF8 == request.getEncode()){
   output.write(request.getCommand().getBytes("UTF-8"));
  }else if(Encode.GBK == request.getEncode()){
   output.write(request.getCommand().getBytes("GBK"));
  }
  output.flush();
 }
 /**
  * 序列化響應(yīng)信息
  * @param output
  * @param response
  */
 public static void writeResponse(OutputStream output, Response response) throws IOException{
  //將response響應(yīng)返回給客戶端
  output.write(response.getEncode());
  //output.write(response.getResponseLength());直接write一個(gè)int類型會(huì)截取低8位傳輸丟棄高24位
  output.write(ByteUtils.int2ByteArray(response.getResponseLength()));
  if(Encode.UTF8 == response.getEncode()){
   output.write(response.getResponse().getBytes("UTF-8"));
  }else if(Encode.GBK == response.getEncode()){
   output.write(response.getResponse().getBytes("GBK"));
  }
  output.flush();
 }
}

七、ByteUtils類的實(shí)現(xiàn)

package com.binghe.utils;

/**
 * 字節(jié)轉(zhuǎn)化工具類
 * @author binghe
 *
 */
public final class ByteUtils {
 /**
  * 將byte數(shù)組轉(zhuǎn)化為int數(shù)字
  * @param bytes
  * @return
  */
 public static int byte2Int(byte[] bytes){
  int num = bytes[3] & 0xFF;
  num |= ((bytes[2] << 8) & 0xFF00);
  num |= ((bytes[1] << 16) & 0xFF0000);
  num |= ((bytes[0] << 24) & 0xFF000000);
  return num;
 }
 
 /**
  * 將int類型數(shù)字轉(zhuǎn)化為byte數(shù)組
  * @param num
  * @return
  */
 public static byte[] int2ByteArray(int i){
  byte[] result = new byte[4];
  result[0]  = (byte)(( i >> 24 ) & 0xFF);
  result[1]  = (byte)(( i >> 16 ) & 0xFF);
  result[2]  = (byte)(( i >> 8 ) & 0xFF);
  result[3]  = (byte)(i & 0xFF);
  return result;
 }
}

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