在Java中可以使用HttpServer類來實現Http服務器，該類位於com.sun.net包下(rt.jar)。實現代碼如下：
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 {
//創建一個HttpServer實例，並綁定到指定的IP地址和端口號
HttpServer httpServer = HttpServer.create(new InetSocketAddress(8080), 0);
//創建一個HttpContext，將路徑為/myserver請求映射到MyHttpHandler處理器
httpServer.createContext("/myserver", new MyHttpHandler());
//設置服務器的線程池對象
httpServer.setExecutor(Executors.newFixedThreadPool(10));
//啟動服務器
httpServer.start();
}
}
HttpServer：HttpServer主要是通過帶參的create方法來創建，第一個參數InetSocketAddress表示綁定的ip地址和端口號。第二個參數為int類型，表示允許排隊的最大TCP連接數，如果該值小於或等於零，則使用系統默認值。
createContext：可以調用多次，表示將指定的url路徑綁定到指定的HttpHandler處理器對象上，服務器接收到的所有路徑請求都將通過調用給定的處理程序對象來處理。
setExecutor：設置服務器的線程池對象，不設置或者設為null則表示使用start方法創建的線程。
HttpHandler實現
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("請求方法：").append(httpExchange.getRequestMethod()).append("<br/>");
responseText.append("請求參數：").append(getRequestParam(httpExchange)).append("<br/>");
responseText.append("請求頭：<br/>").append(getRequestHeader(httpExchange));
handleResponse(httpExchange, responseText.toString());
} catch (Exception ex) {
ex.printStackTrace();
}
}
/**
* 獲取請求頭
* @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/>"));
}
/**
* 獲取請求參數
* @param httpExchange
* @return
* @throws Exception
*/
private String getRequestParam(HttpExchange httpExchange) throws Exception {
String paramStr = "";
if (httpExchange.getRequestMethod().equals("GET")) {
//GET請求讀queryString
paramStr = httpExchange.getRequestURI().getQuery();
} else {
//非GET請求讀請求體
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
* @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");
//設置響應頭，必須在sendResponseHeaders方法之前設置！
httpExchange.getResponseHeaders().add("Content-Type:", "text/html;charset=utf-8");
//設置響應碼和響應體長度，必須在getResponseBody方法之前調用！
httpExchange.sendResponseHeaders(200, responseContentByte.length);
OutputStream out = httpExchange.getResponseBody();
out.write(responseContentByte);
out.flush();
out.close();
}
}
HttpExchange：用於獲取請求內容以及生成和發送響應。
運行HttpServerStarter，在瀏覽器中訪問如下：
