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
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。
其他回答
曾经有一段时间，我正在寻找类似的东西——一个轻量级但功能齐全的HTTP服务器，我可以轻松地嵌入和定制。我发现了两种可能的解决方案:
不是那么轻量级或简单的完整服务器(对于轻量级的极端定义)。 真正的轻量级服务器不是HTTP服务器，而是华丽的ServerSocket示例，甚至不远程兼容rfc，不支持通常需要的基本功能。
所以…我开始编写JLHTTP——Java轻量级HTTP服务器。
您可以将它作为单个(如果相当长)源文件嵌入到任何项目中，或者作为一个~50K的jar (~35K剥离)，没有依赖关系。它努力与rfc兼容，包括大量的文档和许多有用的特性，同时将膨胀保持在最低限度。
Features include: virtual hosts, file serving from disk, mime type mappings via standard mime.types file, directory index generation, welcome files, support for all HTTP methods, conditional ETags and If-* header support, chunked transfer encoding, gzip/deflate compression, basic HTTPS (as provided by the JVM), partial content (download continuation), multipart/form-data handling for file uploads, multiple context handlers via API or annotations, parameter parsing (query string or x-www-form-urlencoded body), etc.
我希望其他人会觉得有用:-)
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());
}
}
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/
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();
}
}
}
httpserver解决方案不能跨jre移植。最好使用javax.xml.ws中的官方webservices API来引导一个最小的HTTP服务器…
import java.io._
import javax.xml.ws._
import javax.xml.ws.http._
import javax.xml.transform._
import javax.xml.transform.stream._
@WebServiceProvider
@ServiceMode(value=Service.Mode.PAYLOAD)
class P extends Provider[Source] {
def invoke(source: Source) = new StreamSource( new StringReader("<p>Hello There!</p>"));
}
val address = "http://127.0.0.1:8080/"
Endpoint.create(HTTPBinding.HTTP_BINDING, new P()).publish(address)
println("Service running at "+address)
println("Type [CTRL]+[C] to quit!")
Thread.sleep(Long.MaxValue)
编辑:这实际上是工作!上面的代码看起来像Groovy之类的。以下是我测试的Java翻译:
import java.io.*;
import javax.xml.ws.*;
import javax.xml.ws.http.*;
import javax.xml.transform.*;
import javax.xml.transform.stream.*;
@WebServiceProvider
@ServiceMode(value = Service.Mode.PAYLOAD)
public class Server implements Provider<Source> {
public Source invoke(Source request) {
return new StreamSource(new StringReader("<p>Hello There!</p>"));
}
public static void main(String[] args) throws InterruptedException {
String address = "http://127.0.0.1:8080/";
Endpoint.create(HTTPBinding.HTTP_BINDING, new Server()).publish(address);
System.out.println("Service running at " + address);
System.out.println("Type [CTRL]+[C] to quit!");
Thread.sleep(Long.MAX_VALUE);
}
}
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