你也可以看看一些NIO应用框架，比如:

网状的:http://jboss.org/netty Apache Mina: http://mina.apache.org/或其子项目AsyncWeb: http://mina.apache.org/asyncweb/

一个非常基本的HTTP服务器在TCP套接字级别的例子:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

public class NaiveHttpServer {

  public static void main(String[] args) throws IOException {
    String hostname = InetAddress.getLocalHost().getHostName();
    ServerSocket serverSocket = new ServerSocket(8089);
    while (true) {
      Socket clientSocket = serverSocket.accept();
      PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
      BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
      String s = in.readLine();
      System.out.println(s);
      while ("\r\n".equals(in.readLine())); 
      if ("GET /hostname HTTP/1.1".equals(s)) {
        out.println("HTTP/1.1 200 OK");
        out.println("Connection: close");
        out.println("Content-Type: text/plain");
        out.println("Content-Length:" + hostname.length());
        out.println();
        out.println(hostname);
      } else {
        out.println("HTTP/1.1 404 Not Found");
        out.println("Connection: close");
        out.println();    
      }
      out.flush();
    }
  }
}

该示例提供计算机的主机名。

检查拍摄。查看https://github.com/yegor256/takes获取快速信息

只需几行代码就可以创建一个仅使用JDK和servlet api提供J2EE servlet基本支持的httpserver。

我发现这对于单元测试servlet非常有用，因为它启动速度比其他轻量级容器快得多(我们在生产中使用jetty)。

大多数非常轻量级的httpserver都不支持servlet，但是我们需要它们，所以我想分享一下。

下面的示例提供了基本的servlet支持，或者为尚未实现的内容抛出和UnsupportedOperationException异常。它使用com.sun.net.httpserver.HttpServer来提供基本的http支持。

import java.io.*;
import java.lang.reflect.*;
import java.net.InetSocketAddress;
import java.util.*;

import javax.servlet.*;
import javax.servlet.http.*;

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;

@SuppressWarnings("deprecation")
public class VerySimpleServletHttpServer {
    HttpServer server;
    private String contextPath;
    private HttpHandler httpHandler;

    public VerySimpleServletHttpServer(String contextPath, HttpServlet servlet) {
        this.contextPath = contextPath;
        httpHandler = new HttpHandlerWithServletSupport(servlet);
    }

    public void start(int port) throws IOException {
        InetSocketAddress inetSocketAddress = new InetSocketAddress(port);
        server = HttpServer.create(inetSocketAddress, 0);
        server.createContext(contextPath, httpHandler);
        server.setExecutor(null);
        server.start();
    }

    public void stop(int secondsDelay) {
        server.stop(secondsDelay);
    }

    public int getServerPort() {
        return server.getAddress().getPort();
    }

}

final class HttpHandlerWithServletSupport implements HttpHandler {

    private HttpServlet servlet;

    private final class RequestWrapper extends HttpServletRequestWrapper {
        private final HttpExchange ex;
        private final Map<String, String[]> postData;
        private final ServletInputStream is;
        private final Map<String, Object> attributes = new HashMap<>();

        private RequestWrapper(HttpServletRequest request, HttpExchange ex, Map<String, String[]> postData, ServletInputStream is) {
            super(request);
            this.ex = ex;
            this.postData = postData;
            this.is = is;
        }

        @Override
        public String getHeader(String name) {
            return ex.getRequestHeaders().getFirst(name);
        }

        @Override
        public Enumeration<String> getHeaders(String name) {
            return new Vector<String>(ex.getRequestHeaders().get(name)).elements();
        }

        @Override
        public Enumeration<String> getHeaderNames() {
            return new Vector<String>(ex.getRequestHeaders().keySet()).elements();
        }

        @Override
        public Object getAttribute(String name) {
            return attributes.get(name);
        }

        @Override
        public void setAttribute(String name, Object o) {
            this.attributes.put(name, o);
        }

        @Override
        public Enumeration<String> getAttributeNames() {
            return new Vector<String>(attributes.keySet()).elements();
        }

        @Override
        public String getMethod() {
            return ex.getRequestMethod();
        }

        @Override
        public ServletInputStream getInputStream() throws IOException {
            return is;
        }

        @Override
        public BufferedReader getReader() throws IOException {
            return new BufferedReader(new InputStreamReader(getInputStream()));
        }

        @Override
        public String getPathInfo() {
            return ex.getRequestURI().getPath();
        }

        @Override
        public String getParameter(String name) {
            String[] arr = postData.get(name);
            return arr != null ? (arr.length > 1 ? Arrays.toString(arr) : arr[0]) : null;
        }

        @Override
        public Map<String, String[]> getParameterMap() {
            return postData;
        }

        @Override
        public Enumeration<String> getParameterNames() {
            return new Vector<String>(postData.keySet()).elements();
        }
    }

    private final class ResponseWrapper extends HttpServletResponseWrapper {
        final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        final ServletOutputStream servletOutputStream = new ServletOutputStream() {

            @Override
            public void write(int b) throws IOException {
                outputStream.write(b);
            }
        };

        private final HttpExchange ex;
        private final PrintWriter printWriter;
        private int status = HttpServletResponse.SC_OK;

        private ResponseWrapper(HttpServletResponse response, HttpExchange ex) {
            super(response);
            this.ex = ex;
            printWriter = new PrintWriter(servletOutputStream);
        }

        @Override
        public void setContentType(String type) {
            ex.getResponseHeaders().add("Content-Type", type);
        }

        @Override
        public void setHeader(String name, String value) {
            ex.getResponseHeaders().add(name, value);
        }

        @Override
        public javax.servlet.ServletOutputStream getOutputStream() throws IOException {
            return servletOutputStream;
        }

        @Override
        public void setContentLength(int len) {
            ex.getResponseHeaders().add("Content-Length", len + "");
        }

        @Override
        public void setStatus(int status) {
            this.status = status;
        }

        @Override
        public void sendError(int sc, String msg) throws IOException {
            this.status = sc;
            if (msg != null) {
                printWriter.write(msg);
            }
        }

        @Override
        public void sendError(int sc) throws IOException {
            sendError(sc, null);
        }

        @Override
        public PrintWriter getWriter() throws IOException {
            return printWriter;
        }

        public void complete() throws IOException {
            try {
                printWriter.flush();
                ex.sendResponseHeaders(status, outputStream.size());
                if (outputStream.size() > 0) {
                    ex.getResponseBody().write(outputStream.toByteArray());
                }
                ex.getResponseBody().flush();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                ex.close();
            }
        }
    }

    public HttpHandlerWithServletSupport(HttpServlet servlet) {
        this.servlet = servlet;
    }

    @SuppressWarnings("deprecation")
    @Override
    public void handle(final HttpExchange ex) throws IOException {
        byte[] inBytes = getBytes(ex.getRequestBody());
        ex.getRequestBody().close();
        final ByteArrayInputStream newInput = new ByteArrayInputStream(inBytes);
        final ServletInputStream is = new ServletInputStream() {

            @Override
            public int read() throws IOException {
                return newInput.read();
            }
        };

        Map<String, String[]> parsePostData = new HashMap<>();

        try {
            parsePostData.putAll(HttpUtils.parseQueryString(ex.getRequestURI().getQuery()));

            // check if any postdata to parse
            parsePostData.putAll(HttpUtils.parsePostData(inBytes.length, is));
        } catch (IllegalArgumentException e) {
            // no postData - just reset inputstream
            newInput.reset();
        }
        final Map<String, String[]> postData = parsePostData;

        RequestWrapper req = new RequestWrapper(createUnimplementAdapter(HttpServletRequest.class), ex, postData, is);

        ResponseWrapper resp = new ResponseWrapper(createUnimplementAdapter(HttpServletResponse.class), ex);

        try {
            servlet.service(req, resp);
            resp.complete();
        } catch (ServletException e) {
            throw new IOException(e);
        }
    }

    private static byte[] getBytes(InputStream in) throws IOException {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        while (true) {
            int r = in.read(buffer);
            if (r == -1)
                break;
            out.write(buffer, 0, r);
        }
        return out.toByteArray();
    }

    @SuppressWarnings("unchecked")
    private static <T> T createUnimplementAdapter(Class<T> httpServletApi) {
        class UnimplementedHandler implements InvocationHandler {
            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                throw new UnsupportedOperationException("Not implemented: " + method + ", args=" + Arrays.toString(args));
            }
        }

        return (T) Proxy.newProxyInstance(UnimplementedHandler.class.getClassLoader(),
                new Class<?>[] { httpServletApi },
                new UnimplementedHandler());
    }
}

我玩得很开心，我玩转了一下，拼凑出了这个。我希望这对你有所帮助。 你需要安装Gradle或者使用Maven插件。

build.gradle

plugins {
    id 'application'
}

group 'foo.bar'
version '1.0'

repositories {
    mavenCentral()
}

application{
    mainClass.set("foo.FooServer")
}

dependencies {}

FooServer 主入口点，你的主类。

package foo;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class FooServer {

    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(7654);
        serverSocket.setPerformancePreferences(0, 1, 2);

        /* the higher the numbers, the better the concurrent performance, ha!
           we found that a 3:7 ratio to be optimal
           3 partitioned executors to 7 network executors */

        ExecutorService executors = Executors.newFixedThreadPool(3);
        executors.execute(new PartitionedExecutor(serverSocket));
    }


    public static class PartitionedExecutor implements Runnable {
        ServerSocket serverSocket;

        public PartitionedExecutor(ServerSocket serverSocket) {
            this.serverSocket = serverSocket;
        }

        @Override
        public void run() {
            ExecutorService executors = Executors.newFixedThreadPool(30);
            executors.execute(new NetworkRequestExecutor(serverSocket, executors));
        }
    }


    public static class NetworkRequestExecutor implements Runnable{

        String IGNORE_CHROME = "/favicon.ico";
        String BREAK = "\r\n";
        String DOUBLEBREAK = "\r\n\r\n";

        Integer REQUEST_METHOD = 0;
        Integer REQUEST_PATH = 1;
        Integer REQUEST_VERSION = 2;

        String RENDERER;

        Socket socketClient;
        ExecutorService executors;
        ServerSocket serverSocket;

        public NetworkRequestExecutor(ServerSocket serverSocket, ExecutorService executors){
            this.serverSocket = serverSocket;
            this.executors = executors;
        }

        @Override
        public void run() {
            try {

                socketClient = serverSocket.accept();
                Thread.sleep(19);//do this for safari, its a hack but safari requires something like this.
                InputStream requestInputStream = socketClient.getInputStream();

                OutputStream clientOutput = socketClient.getOutputStream();

                if (requestInputStream.available() == 0) {
                    requestInputStream.close();
                    clientOutput.flush();
                    clientOutput.close();
                    executors.execute(new NetworkRequestExecutor(serverSocket, executors));
                    return;
                }

                ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
                ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
                int bytesRead;
                while ((bytesRead = requestInputStream.read(byteBuffer.array())) != -1) {
                    byteArrayOutputStream.write(byteBuffer.array(), 0, bytesRead);
                    if (requestInputStream.available() == 0) break;
                }

                String completeRequestContent = byteArrayOutputStream.toString();
                String[] requestBlocks = completeRequestContent.split(DOUBLEBREAK, 2);

                String headerComponent = requestBlocks[0];
                String[] methodPathComponentsLookup = headerComponent.split(BREAK);
                String methodPathComponent = methodPathComponentsLookup[0];

                String[] methodPathVersionComponents = methodPathComponent.split("\\s");

                String requestVerb = methodPathVersionComponents[REQUEST_METHOD];
                String requestPath = methodPathVersionComponents[REQUEST_PATH];
                String requestVersion = methodPathVersionComponents[REQUEST_VERSION];


                if (requestPath.equals(IGNORE_CHROME)) {
                    requestInputStream.close();
                    clientOutput.flush();
                    clientOutput.close();
                    executors.execute(new NetworkRequestExecutor(serverSocket, executors));
                    return;
                }

                ConcurrentMap<String, String> headers = new ConcurrentHashMap<>();
                String[] headerComponents = headerComponent.split(BREAK);
                for (String headerLine : headerComponents) {
                    String[] headerLineComponents = headerLine.split(":");
                    if (headerLineComponents.length == 2) {
                        String fieldKey = headerLineComponents[0].trim();
                        String content = headerLineComponents[1].trim();
                        headers.put(fieldKey.toLowerCase(), content);
                    }
                }

                clientOutput.write("HTTP/1.1 200 OK".getBytes());
                clientOutput.write(BREAK.getBytes());

                Integer bytesLength = "hi".length();
                String contentLengthBytes = "Content-Length:" + bytesLength;
                clientOutput.write(contentLengthBytes.getBytes());
                clientOutput.write(BREAK.getBytes());

                clientOutput.write("Server: foo server".getBytes());
                clientOutput.write(BREAK.getBytes());

                clientOutput.write("Content-Type: text/html".getBytes());

                clientOutput.write(DOUBLEBREAK.getBytes());
                clientOutput.write("hi".getBytes());

                clientOutput.close();
                socketClient.close();

                executors.execute(new NetworkRequestExecutor(serverSocket, executors));

            } catch (IOException ex) {
                ex.printStackTrace();
            } catch (InterruptedException ioException) {
                ioException.printStackTrace();
            }
        }
    }
}

运行该程序:

gradle run

浏览:

http://localhost:7654/

从Java SE 6开始，在Sun Oracle JRE中有一个内置的HTTP服务器。Java 9模块名称为jdk.httpserver。httpserver包摘要概述了涉及的类并包含示例。

这里有一个从他们的文档复制粘贴的启动示例。你可以复制，粘贴，然后在Java 6+上运行。 (尽管如此，所有试图编辑它的人，因为它是一段丑陋的代码，请不要，这是一个复制粘贴，不是我的，此外，你不应该编辑引文，除非它们在原始来源中发生了变化)

package com.stackoverflow.q3732109; import java.io.IOException; import java.io.OutputStream; import java.net.InetSocketAddress; import com.sun.net.httpserver.HttpExchange; import com.sun.net.httpserver.HttpHandler; import com.sun.net.httpserver.HttpServer; public class Test { public static void main(String[] args) throws Exception { HttpServer server = HttpServer.create(new InetSocketAddress(8000), 0); server.createContext("/test", new MyHandler()); server.setExecutor(null); // creates a default executor server.start(); } static class MyHandler implements HttpHandler { @Override public void handle(HttpExchange t) throws IOException { String response = "This is the response"; t.sendResponseHeaders(200, response.length()); OutputStream os = t.getResponseBody(); os.write(response.getBytes()); os.close(); } } }

应该注意的是，他们示例中的response.length()部分是坏的，它应该是response.getBytes().length。即使这样，getBytes()方法也必须显式地指定在响应头中指定的字符集。唉，尽管对初学者有误导，但毕竟这只是一个基本的启动示例。

执行它并访问http://localhost:8000/test，你将看到以下响应:

这是反应

As to using com.sun.* classes, do note that this is, in contrary to what some developers think, absolutely not forbidden by the well known FAQ Why Developers Should Not Write Programs That Call 'sun' Packages. That FAQ concerns the sun.* package (such as sun.misc.BASE64Encoder) for internal usage by the Oracle JRE (which would thus kill your application when you run it on a different JRE), not the com.sun.* package. Sun/Oracle also just develop software on top of the Java SE API themselves like as every other company such as Apache and so on. Moreover, this specific HttpServer must be present in every JDK so there is absolutely no means of "portability" issue like as would happen with sun.* package. Using com.sun.* classes is only discouraged (but not forbidden) when it concerns an implementation of a certain Java API, such as GlassFish (Java EE impl), Mojarra (JSF impl), Jersey (JAX-RS impl), etc.