Embedding Jetty 创建简单的内嵌服务器

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一. 创建内嵌的Jetty服务器主要有以下几个步骤：

（1）创建一个Server实例

（2）添加或者配置一个Connectors

（3）添加或者配置 Handler and/or Contexts and/or Servlet

（4）启动Server

（5）等待服务，或者使用线程做一些其他的事情

二. 创建一个最简单的服务器

由于该服务器没有处理程序handler，所以它将会对所有的请求返回404

packageorg.eclipse.jetty.embedded; importorg.eclipse.jetty.server.Server; /** The simplest possible Jetty server. */publicclass SimplestServer {     publicstatic void main(String[] args) throwsException {        Server server = newServer(8080);        server.start();        server.join();    }}

三. 使用Handler

为了对一个request产生response ,Jetty需要为server添加一个Handler处理程序。一个Handler处理程序可以有以下几中行为：

1. 检查或者修改HTTP request
2. 产生完整的HTTP response
3. 调用其它的Handler处理程序
4. 选择一个或多个Handlers去调用

下面实例是一个简单的Handler处理程序

packageorg.eclipse.jetty.embedded; importjava.io.IOException;importjavax.servlet.ServletException;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;importorg.eclipse.jetty.server.Request;importorg.eclipse.jetty.server.handler.AbstractHandler; publicclass HelloHandler extendsAbstractHandler {     finalString _greeting;     finalString _body;     publicHelloHandler() {        _greeting = "Hello World";        _body = null;    }     publicHelloHandler(String greeting) {        _greeting = greeting;        _body = null;    }     publicHelloHandler(String greeting, String body) {        _greeting = greeting;        _body = body;    }     publicvoid handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response)throwsIOException, ServletException {        response.setContentType("text/html;charset=utf-8");        response.setStatus(HttpServletResponse.SC_OK);        baseRequest.setHandled(true);        response.getWriter().println("<h1>"+ _greeting + "</h1>");        if(_body != null) response.getWriter().println(_body);    }}

传递给handle方法的参数有以下几个：

target–the target of the request, which is either a URI or a name from a named dispatcher.
baseRequest–the Jetty mutable request object, which is always unwrapped.
request–the immutable request object, which may have been wrapped by a filter or servlet.
response–the response, which may have been wrapped by a filter or servlet.

四. 运行HelloWordHandler

publicstatic void main(String[] args) throwsException {    Server server = newServer(8080);    server.setHandler(newHelloHandler());    server.start();    server.join();}

五. 资源处理程序 Resource Handler

FileServer类展示如何使用ResourceHandler来提供对静态资源的服务。

packageorg.eclipse.jetty.embedded; importorg.eclipse.jetty.server.Handler;importorg.eclipse.jetty.server.Server;importorg.eclipse.jetty.server.handler.DefaultHandler;importorg.eclipse.jetty.server.handler.HandlerList;importorg.eclipse.jetty.server.handler.ResourceHandler; /** Simple Jetty FileServer. * This is a simple example of Jetty configured as a FileServer. */publicclass FileServer {     publicstatic void main(String[] args) throwsException {        Server server = newServer(8080);        ResourceHandler resource_handler = newResourceHandler();        resource_handler.setDirectoriesListed(true);        resource_handler.setWelcomeFiles(newString[] { "index.html"});        resource_handler.setResourceBase(".");        HandlerList handlers = newHandlerList();        handlers.setHandlers(newHandler[] { resource_handler, newDefaultHandler() });        server.setHandler(handlers);        server.start();        server.join();    }}

对于不匹配该静态资源的请求将会返回一个404，对于不匹配静态资源的请求，有DefaultHandler实例处理，返回404

六. 内嵌的连接器 Embedding Connectors

在上面的例子中，一个Server实例被传入了一个端口号，在Server内部默认的创建了一个连接器Connector用来坚挺该端口的请求。然而，许多时候默认的连接器并不能够满足一些需要，所以需要自定义自己的Connectors.

OneConnector.java 实例化，配置，并且添加了一个简单的HTTP连接器实例的Server

packageorg.eclipse.jetty.embedded; importorg.eclipse.jetty.server.Server;importorg.eclipse.jetty.server.ServerConnector; /** * A Jetty server with one connectors. */publicclass OneConnector {     publicstatic void main(String[] args) throwsException {        Server server = newServer();        ServerConnector http = newServerConnector(server);        http.setHost("localhost");        http.setPort(8080);        http.setIdleTimeout(30000);        server.addConnector(http);        server.setHandler(newHelloHandler());        server.start();        server.join();    }}

七. 多个连接器

当配置多个Connector，比如HTTP，HTTPS，可能更希望共享一些HTTP配置参数，为了实现这个目标，需要指定为ServerConnector配置一个ConnectionFactory,并且提供一些可以共享的常用参数。

ManyConnectors.java配置了两个连接器，分别是http connector 和 https connector,该实例在本文最下方。

八，内嵌Servlet (Embedding Servlet）

Servlet提供了处理http请求的标准方式，Servlet和Jetty的Handler是相似的，除了它的request对象是不能够修改的。Servlet在jetty中是通过ServletHandler处理类来处理的。它使用标准的路径映射(path mapping)来匹配Servlet请求。MinimalServlet.java 创建了一个ServletHandler实例，并且配置了一个简单的HelloServlet。

packageorg.eclipse.jetty.embedded; importjava.io.IOException;importjavax.servlet.ServletException;importjavax.servlet.http.HttpServlet;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;importorg.eclipse.jetty.server.Server;importorg.eclipse.jetty.servlet.ServletHandler; publicclass MinimalServlets {     publicstatic void main(String[] args) throwsException {        Server server = newServer(8080);        ServletHandler handler = newServletHandler();        server.setHandler(handler);        handler.addServletWithMapping(HelloServlet.class,"/*");        server.start();        server.join();    }     @SuppressWarnings("serial")    publicstatic class HelloServlet extendsHttpServlet {         @Override        protectedvoid doGet(HttpServletRequest request, HttpServletResponse response) throwsServletException, IOException {            response.setContentType("text/html");            response.setStatus(HttpServletResponse.SC_OK);            response.getWriter().println("<h1>Hello SimpleServlet</h1>");        }    }}

八. 内嵌的上下文 Embedding Contexts

ContextHandler是只对匹配所属context的URI前缀请求响应的ScopedHandler，每一个匹配上下文url的请求，都有一个对应的handler，有效的上下文（context)主要有以下几种：

A Classloader that is set as the Thread context classloader while request handling is in scope.
A set of attributes that is available via the ServletContext API.
A set of init parameters that is available via the ServletContext API.
A base Resource which is used as the document root for static resource requests via the ServletContext API.
A set of virtual host names.

下面的例子 OneContext.java 展示了建立一个包裹一个简单handler的context

packageorg.eclipse.jetty.embedded; importorg.eclipse.jetty.server.Server;importorg.eclipse.jetty.server.handler.ContextHandler; publicclass OneContext {     publicstatic void main(String[] args) throwsException {        Server server = newServer(8080);        ContextHandler context = newContextHandler();        context.setContextPath("/");        context.setResourceBase(".");        context.setClassLoader(Thread.currentThread().getContextClassLoader());        context.setHandler(newHelloHandler());        server.setHandler(context);        server.start();        server.join();    }}

当有许多上下文时，可以使用 ContextHandlerCollection 来有效的管理 ContextHandler,下面的实例展示了这一点：

packageorg.eclipse.jetty.embedded; importorg.eclipse.jetty.server.Handler;importorg.eclipse.jetty.server.Server;importorg.eclipse.jetty.server.handler.ContextHandler;importorg.eclipse.jetty.server.handler.ContextHandlerCollection; publicclass ManyContexts {     publicstatic void main(String[] args) throwsException {        Server server = newServer(8080);        ContextHandler context = newContextHandler("/");        context.setContextPath("/");        context.setHandler(newHelloHandler("Root Hello"));        ContextHandler contextFR = newContextHandler("/fr");        contextFR.setHandler(newHelloHandler("Bonjoir"));        ContextHandler contextIT = newContextHandler("/it");        contextIT.setHandler(newHelloHandler("Bongiorno"));        ContextHandler contextV = newContextHandler("/");        contextV.setVirtualHosts(newString[] { "127.0.0.2"});        contextV.setHandler(newHelloHandler("Virtual Hello"));        ContextHandlerCollection contexts = newContextHandlerCollection();        contexts.setHandlers(newHandler[] { context, contextFR, contextIT, contextV });        server.setHandler(contexts);        server.start();        server.join();    }}

九. 内嵌多个Servlet上下文 Embedding ServletContexts

ServletContextHandler是一个专门支持Session和Servlets的上下文处理程序ContextHandler，下面的实例展示了这一点，其中DefaultServlet是一个继承HttpServlet的简单Servlet.

packageorg.eclipse.jetty.embedded; importorg.eclipse.jetty.server.Server;importorg.eclipse.jetty.servlet.ServletContextHandler;importorg.eclipse.jetty.servlet.ServletHolder; publicclass OneServletContext {     publicstatic void main(String[] args) throwsException {        Server server = newServer(8080);        ServletContextHandler context = newServletContextHandler(ServletContextHandler.SESSIONS);        context.setContextPath("/");        server.setHandler(context);        context.addServlet(org.eclipse.jetty.servlet.DefaultServlet.class,"/");        context.addServlet(newServletHolder(newDumpServlet()), "/dump/*");        server.start();        server.join();    }}

附录：

import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;/*** Created by superman on 14-1-11.*/public class DumpServlet extends HttpServlet{    @Override    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        response.setContentType("text/html");        response.setStatus(HttpServletResponse.SC_OK);        response.getWriter().println("<h1>DumpServlet</h1><pre>");        response.getWriter().println("requestURI=" + request.getRequestURI());        response.getWriter().println("contextPath=" + request.getContextPath());        response.getWriter().println("servletPath=" + request.getServletPath());        response.getWriter().println("pathInfo=" + request.getPathInfo());        response.getWriter().println("session=" + request.getSession(true).getId());        String r=request.getParameter("resource");        if (r!=null)            response.getWriter().println("resource("+r+")=" + getServletContext().getResource(r));        response.getWriter().println("</pre>");    }}

package jetty;import org.eclipse.jetty.server.*;import org.eclipse.jetty.util.ssl.SslContextFactory;/*** Created by superman on 14-1-11.*/public class ManyConnectors {public static void main(String[] args) throws Exception {        String jetty_home = System.getProperty("jetty.home", "D:\\jetty-distribution-9.1.0.v20131115");        System.setProperty("jetty.home", jetty_home);        Server server = new Server();//configure some common parameters        HttpConfiguration httpConfig = new HttpConfiguration();        httpConfig.setSecureScheme("https");        httpConfig.setSecurePort(8443);        httpConfig.setOutputBufferSize(32768);// HTTP connector// The first server connector we create is the one for http, passing in the http configuration we configured// above so it can get things like the output buffer size, etc. We also set the port (8080) and configure an// idle timeout.        ServerConnector httpConnector = new ServerConnector(server, new HttpConnectionFactory(httpConfig));        httpConnector.setPort(8080);        httpConnector.setIdleTimeout(30000);// SSL Context Factory for HTTPS and SPDY// SSL requires a certificate so we configure a factory for ssl contents with information pointing to what// keystore the ssl connection needs to know about. Much more configuration is available the ssl context,// including things like choosing the particular certificate out of a keystore to be used.69        SslContextFactory sslContextFactory = new SslContextFactory();        sslContextFactory.setKeyStorePath(jetty_home + "/etc/keystore");        sslContextFactory.setKeyStorePassword("OBF:1vny1zlo1x8e1vnw1vn61x8g1zlu1vn4");        sslContextFactory.setKeyManagerPassword("OBF:1u2u1wml1z7s1z7a1wnl1u2g");// HTTPS Configuration// A new HttpConfiguration object is needed for the next connector and you can pass the old one as an// argument to effectively clone the contents. On this HttpConfiguration object we add a// SecureRequestCustomizer which is how a new connector is able to resolve the https connection before// handing control over to the Jetty Server.        HttpConfiguration https_config = new HttpConfiguration(httpConfig);        https_config.addCustomizer(new SecureRequestCustomizer());// HTTPS connector// We create a second ServerConnector, passing in the http configuration we just made along with the// previously created ssl context factory. Next we set the port and a longer idle timeout.        ServerConnector https = new ServerConnector(server,new SslConnectionFactory(sslContextFactory, "http/1.1"),new HttpConnectionFactory(https_config));        https.setPort(8443);        https.setIdleTimeout(500000);        server.setConnectors(new Connector[]{httpConnector, https});        server.setHandler(new HelloWorldHandler("hello", "welcome"));        server.start();        server.join();    }}

翻译来源:http://www.eclipse.org/jetty/documentation/current/index.html

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