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Java 如何實(shí)現(xiàn)一個(gè)http服務(wù)器

更新時(shí)間：2020年11月20日 12:02:16 作者：自律給我自由

這篇文章主要介紹了Java 如何實(shí)現(xiàn)一個(gè)http服務(wù)器，幫助大家更好的理解和學(xué)習(xí)Java，感興趣的朋友可以了解下

在Java中可以使用HttpServer類來實(shí)現(xiàn)Http服務(wù)器，該類位于com.sun.net包下(rt.jar)。實(shí)現(xiàn)代碼如下：

主程序類

package bg.httpserver;

import com.sun.net.httpserver.HttpServer;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.concurrent.Executors;

public class HttpServerStarter {
  public static void main(String[] args) throws IOException {
    //創(chuàng)建一個(gè)HttpServer實(shí)例，并綁定到指定的IP地址和端口號(hào)
    HttpServer httpServer = HttpServer.create(new InetSocketAddress(8080), 0);

    //創(chuàng)建一個(gè)HttpContext，將路徑為/myserver請(qǐng)求映射到MyHttpHandler處理器
    httpServer.createContext("/myserver", new MyHttpHandler());

    //設(shè)置服務(wù)器的線程池對(duì)象
    httpServer.setExecutor(Executors.newFixedThreadPool(10));

    //啟動(dòng)服務(wù)器
    httpServer.start();
  }
}

HttpServer：HttpServer主要是通過帶參的create方法來創(chuàng)建，第一個(gè)參數(shù)InetSocketAddress表示綁定的ip地址和端口號(hào)。第二個(gè)參數(shù)為int類型，表示允許排隊(duì)的最大TCP連接數(shù)，如果該值小于或等于零，則使用系統(tǒng)默認(rèn)值。

createContext：可以調(diào)用多次，表示將指定的url路徑綁定到指定的HttpHandler處理器對(duì)象上，服務(wù)器接收到的所有路徑請(qǐng)求都將通過調(diào)用給定的處理程序?qū)ο髞硖幚怼?/p>

setExecutor：設(shè)置服務(wù)器的線程池對(duì)象，不設(shè)置或者設(shè)為null則表示使用start方法創(chuàng)建的線程。

HttpHandler實(shí)現(xiàn)

package bg.httpserver;

import com.sun.net.httpserver.Headers;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

/**
 * 處理/myserver路徑請(qǐng)求的處理器類
 */
public class MyHttpHandler implements HttpHandler {
  @Override
  public void handle(HttpExchange httpExchange) {
    try {
      StringBuilder responseText = new StringBuilder();
      responseText.append("請(qǐng)求方法：").append(httpExchange.getRequestMethod()).append("<br/>");
      responseText.append("請(qǐng)求參數(shù)：").append(getRequestParam(httpExchange)).append("<br/>");
      responseText.append("請(qǐng)求頭：<br/>").append(getRequestHeader(httpExchange));
      handleResponse(httpExchange, responseText.toString());
    } catch (Exception ex) {
      ex.printStackTrace();
    }
  }

  /**
   * 獲取請(qǐng)求頭
   * @param httpExchange
   * @return
   */
  private String getRequestHeader(HttpExchange httpExchange) {
    Headers headers = httpExchange.getRequestHeaders();
    return headers.entrySet().stream()
                .map((Map.Entry<String, List<String>> entry) -> entry.getKey() + ":" + entry.getValue().toString())
                .collect(Collectors.joining("<br/>"));
  }

  /**
   * 獲取請(qǐng)求參數(shù)
   * @param httpExchange
   * @return
   * @throws Exception
   */
  private String getRequestParam(HttpExchange httpExchange) throws Exception {
    String paramStr = "";

    if (httpExchange.getRequestMethod().equals("GET")) {
      //GET請(qǐng)求讀queryString
      paramStr = httpExchange.getRequestURI().getQuery();
    } else {
      //非GET請(qǐng)求讀請(qǐng)求體
      BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(httpExchange.getRequestBody(), "utf-8"));
      StringBuilder requestBodyContent = new StringBuilder();
      String line = null;
      while ((line = bufferedReader.readLine()) != null) {
        requestBodyContent.append(line);
      }
      paramStr = requestBodyContent.toString();
    }

    return paramStr;
  }

  /**
   * 處理響應(yīng)
   * @param httpExchange
   * @param responsetext
   * @throws Exception
   */
  private void handleResponse(HttpExchange httpExchange, String responsetext) throws Exception {
    //生成html
    StringBuilder responseContent = new StringBuilder();
    responseContent.append("<html>")
        .append("<body>")
        .append(responsetext)
        .append("</body>")
        .append("</html>");
    String responseContentStr = responseContent.toString();
    byte[] responseContentByte = responseContentStr.getBytes("utf-8");

    //設(shè)置響應(yīng)頭，必須在sendResponseHeaders方法之前設(shè)置！
    httpExchange.getResponseHeaders().add("Content-Type:", "text/html;charset=utf-8");

    //設(shè)置響應(yīng)碼和響應(yīng)體長度，必須在getResponseBody方法之前調(diào)用！
    httpExchange.sendResponseHeaders(200, responseContentByte.length);

    OutputStream out = httpExchange.getResponseBody();
    out.write(responseContentByte);
    out.flush();
    out.close();
  }
}

運(yùn)行HttpServerStarter，在瀏覽器中訪問如下：