是否有一种方法可以使用Java SE API在Java中创建一个非常基本的HTTP服务器(只支持GET/POST),而不需要编写代码手动解析HTTP请求和手动格式化HTTP响应?Java SE API在HttpURLConnection中很好地封装了HTTP客户机功能,但是是否有类似的HTTP服务器功能呢?

需要明确的是,我在网上看到的许多ServerSocket示例的问题是,它们自己进行请求解析/响应格式化和错误处理,这很乏味,容易出错,而且不太全面,出于这些原因,我试图避免使用它。


当前回答

以上所有的回答关于单主线程请求处理器的细节。

设置:

 server.setExecutor(java.util.concurrent.Executors.newCachedThreadPool());

允许多个请求服务通过多个线程使用执行器服务。

因此,结束代码将如下所示:

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 App {
    public static void main(String[] args) throws Exception {
        HttpServer server = HttpServer.create(new InetSocketAddress(8000), 0);
        server.createContext("/test", new MyHandler());
        //Thread control is given to executor service.
        server.setExecutor(java.util.concurrent.Executors.newCachedThreadPool());
        server.start();
    }
    static class MyHandler implements HttpHandler {
        @Override
        public void handle(HttpExchange t) throws IOException {
            String response = "This is the response";
            long threadId = Thread.currentThread().getId();
            System.out.println("I am thread " + threadId );
            response = response + "Thread Id = "+threadId;
            t.sendResponseHeaders(200, response.length());
            OutputStream os = t.getResponseBody();
            os.write(response.getBytes());
            os.close();
        }
    }
}

其他回答

您可以编写一个非常简单的嵌入式Jetty Java服务器。

嵌入式Jetty意味着服务器(Jetty)与应用程序一起发布,而不是将应用程序部署在外部Jetty服务器上。

因此,如果在非嵌入式方法中,你的webapp内置到WAR文件中,并部署到一些外部服务器(Tomcat / Jetty / etc),在嵌入式Jetty中,你在相同的代码库中编写webapp并实例化Jetty服务器。

一个嵌入式Jetty Java服务器的例子,你可以git克隆和使用:https://github.com/stas-slu/embedded-jetty-java-server-example

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());
    }
}

这个代码比我们的代码更好,你只需要添加2个库:javax. servlet .jar和org.mortbay.jetty.jar。

类码头:

package jetty;

import java.util.logging.Level;
import java.util.logging.Logger;
import org.mortbay.http.SocketListener;
import org.mortbay.jetty.Server;
import org.mortbay.jetty.servlet.ServletHttpContext;

public class Jetty {

    public static void main(String[] args) {
        try {
            Server server = new Server();
            SocketListener listener = new SocketListener();      

            System.out.println("Max Thread :" + listener.getMaxThreads() + " Min Thread :" + listener.getMinThreads());

            listener.setHost("localhost");
            listener.setPort(8070);
            listener.setMinThreads(5);
            listener.setMaxThreads(250);
            server.addListener(listener);            

            ServletHttpContext context = (ServletHttpContext) server.getContext("/");
            context.addServlet("/MO", "jetty.HelloWorldServlet");

            server.start();
            server.join();

        /*//We will create our server running at http://localhost:8070
        Server server = new Server();
        server.addListener(":8070");

        //We will deploy our servlet to the server at the path '/'
        //it will be available at http://localhost:8070
        ServletHttpContext context = (ServletHttpContext) server.getContext("/");
        context.addServlet("/MO", "jetty.HelloWorldServlet");

        server.start();
        */

        } catch (Exception ex) {
            Logger.getLogger(Jetty.class.getName()).log(Level.SEVERE, null, ex);
        }

    }
} 

Servlet类:

package jetty;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class HelloWorldServlet extends HttpServlet
{
    @Override
    protected void doGet(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws ServletException, IOException
    {
        String appid = httpServletRequest.getParameter("appid");
        String conta = httpServletRequest.getParameter("conta");

        System.out.println("Appid : "+appid);
        System.out.println("Conta : "+conta);

        httpServletResponse.setContentType("text/plain");
        PrintWriter out = httpServletResponse.getWriter();
        out.println("Hello World!");
        out.close();
    }
}

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/

Apache Commons HttpCore项目怎么样?

来自网站:…… HttpCore目标

实现最基本的HTTP传输方面 良好的表现和清晰的表达之间的平衡 API 小(可预测的)内存占用 自包含库(没有JRE以外的外部依赖)