Embedding Jetty 创建简单的内嵌服务器

时间：2022-09-25 15:36:05

 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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