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簡單實現(xiàn)Java web服務(wù)器

更新時間：2016年06月21日 08:37:50 作者：風(fēng)一樣的碼農(nóng)

這篇文章主要為大家詳細介紹了簡單實現(xiàn)Java web服務(wù)器的詳細步驟，感興趣的小伙伴們可以參考一下

一個簡單的Java web服務(wù)器實現(xiàn)，比較簡單，基于java.net.Socket和java.net.ServerSocket實現(xiàn)；
一、程序執(zhí)行步驟
1.創(chuàng)建一個ServerSocket對象；
2.調(diào)用ServerSocket對象的accept方法，等待連接，連接成功會返回一個Socket對象，否則一直阻塞等待；
3.從Socket對象中獲取InputStream和OutputStream字節(jié)流，這兩個流分別對應(yīng)request請求和response響應(yīng)；
4.處理請求：讀取InputStream字節(jié)流信息，轉(zhuǎn)成字符串形式，并解析，這里的解析比較簡單，僅僅獲取uri(統(tǒng)一資源標(biāo)識符)信息;
5.處理響應(yīng)：根據(jù)解析出來的uri信息，從WEB_ROOT目錄中尋找請求的資源資源文件, 讀取資源文件，并將其寫入到OutputStream字節(jié)流中；
6.關(guān)閉Socket對象；
7.轉(zhuǎn)到步驟2，繼續(xù)等待連接請求；

二、代碼實現(xiàn)

服務(wù)器實現(xiàn)：

package ex01.pyrmont;

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

public class HttpServer {

 /**
 * WEB_ROOT是HTML和其它文件存放的目錄. 這里的WEB_ROOT為工作目錄下的webroot目錄
 */
 public static final String WEB_ROOT = System.getProperty("user.dir") + File.separator + "webroot";

 // 關(guān)閉服務(wù)命令
 private static final String SHUTDOWN_COMMAND = "/SHUTDOWN";

 public static void main(String[] args) {
 HttpServer server = new HttpServer();
 //等待連接請求
 server.await();
 }

 public void await() {
 ServerSocket serverSocket = null;
 int port = 8080;
 try {
  //服務(wù)器套接字對象
  serverSocket = new ServerSocket(port, 1, InetAddress.getByName("127.0.0.1"));
 } catch (IOException e) {
  e.printStackTrace();
  System.exit(1);
 }

 // 循環(huán)等待一個請求
 while (true) {
  Socket socket = null;
  InputStream input = null;
  OutputStream output = null;
  try {
  //等待連接，連接成功后，返回一個Socket對象
  socket = serverSocket.accept();
  input = socket.getInputStream();
  output = socket.getOutputStream();

  // 創(chuàng)建Request對象并解析
  Request request = new Request(input);
  request.parse();
  // 檢查是否是關(guān)閉服務(wù)命令
  if (request.getUri().equals(SHUTDOWN_COMMAND)) {
   break;
  }

  // 創(chuàng)建 Response 對象
  Response response = new Response(output);
  response.setRequest(request);
  response.sendStaticResource();

  // 關(guān)閉 socket 對象
  socket.close();
  
  } catch (Exception e) {
  e.printStackTrace();
  continue;
  }
 }
 }
}

Request類：

package ex01.pyrmont;

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

public class Request {

 private InputStream input;
 private String uri;

 public Request(InputStream input) {
 this.input = input;
 }

 //從InputStream中讀取request信息，并從request中獲取uri值
 public void parse() {
 StringBuffer request = new StringBuffer(2048);
 int i;
 byte[] buffer = new byte[2048];
 try {
  i = input.read(buffer);
 } catch (IOException e) {
  e.printStackTrace();
  i = -1;
 }
 for (int j = 0; j < i; j++) {
  request.append((char) buffer[j]);
 }
 System.out.print(request.toString());
 uri = parseUri(request.toString());
 }

 /**
 * 
 * requestString形式如下：
 * GET /index.html HTTP/1.1
 * Host: localhost:8080
 * Connection: keep-alive
 * Cache-Control: max-age=0
 * ...
 * 該函數(shù)目的就是為了獲取/index.html字符串
 */
 private String parseUri(String requestString) {
 int index1, index2;
 index1 = requestString.indexOf(' ');
 if (index1 != -1) {
  index2 = requestString.indexOf(' ', index1 + 1);
  if (index2 > index1)
  return requestString.substring(index1 + 1, index2);
 }
 return null;
 }

 public String getUri() {
 return uri;
 }

}

Response類：

 package ex01.pyrmont;

import java.io.OutputStream;
import java.io.IOException;
import java.io.FileInputStream;
import java.io.File;

/*
 HTTP Response = Status-Line
 *(( general-header | response-header | entity-header ) CRLF)
 CRLF
 [ message-body ]
 Status-Line = HTTP-Version SP Status-Code SP Reason-Phrase CRLF
*/

public class Response {

 private static final int BUFFER_SIZE = 1024;
 Request request;
 OutputStream output;

 public Response(OutputStream output) {
 this.output = output;
 }

 public void setRequest(Request request) {
 this.request = request;
 }

 public void sendStaticResource() throws IOException {
 byte[] bytes = new byte[BUFFER_SIZE];
 FileInputStream fis = null;
 try {
  //將web文件寫入到OutputStream字節(jié)流中
  File file = new File(HttpServer.WEB_ROOT, request.getUri());
  if (file.exists()) {
  fis = new FileInputStream(file);
  int ch = fis.read(bytes, 0, BUFFER_SIZE);
  while (ch != -1) {
   output.write(bytes, 0, ch);
   ch = fis.read(bytes, 0, BUFFER_SIZE);
  }
  } else {
  // file not found
  String errorMessage = "HTTP/1.1 404 File Not Found\r\n" + "Content-Type: text/html\r\n"
   + "Content-Length: 23\r\n" + "\r\n" + "<h1>File Not Found</h1>";
  output.write(errorMessage.getBytes());
  }
 } catch (Exception e) {
  // thrown if cannot instantiate a File object
  System.out.println(e.toString());
 } finally {
  if (fis != null)
  fis.close();
 }
 }
}

三、結(jié)果測試

訪問存在的資源文件(注意存放在工程目錄的webroot文件夾里)：