jetty9内嵌到应用，并在启动后加载WebApplicationInitializer，可运行jsp

声明：本文所介绍的两功能都已经测试通过。

第一步先确保你用的是java 8,并依赖需要的相关jar包，以下是用gradle进行依赖的信息：

ext {
taglibsStandardVersion = "1.2.5"
ecjVersion = "4.4.2"
apacheJspVersion = "6.9.10"
asmVersion = "5.0.1"
tomcatVersion = "8.0.30"
annotationApiVersion = "1.2"
jettySchemasVersion = "3.1"
jettyVersion = "9.3.7.v20160115"
servletApiVersion = "3.1.0"
hamcrestCoreVersion = "5.0.1"
commonsLoggingVersion = "1.2"
springVersion = "4.2.3.RELEASE"

}

dependencies {

  compile("spring-web:spring-web:${springVersion}")
    compile("spring-aop:spring-aop:${springVersion}")
    compile("spring-beans:spring-beans:${springVersion}")
    compile("spring-context:spring-context:${springVersion}")
    compile("spring-expression:spring-expression:${springVersion}")
    compile("spring-core:spring-core:${springVersion}")
    compile("commons-logging:commons-logging:${commonsLoggingVersion}")
    compile("javax.servlet-api:javax.servlet-api:${servletApiVersion}")
    compile("hamcrest-core:hamcrest-core:${hamcrestCoreVersion}")
    compile("jetty-annotations:jetty-annotations:${jettyVersion}")
    compile("jetty-plus:jetty-plus:${jettyVersion}")
    compile("jetty-jndi:jetty-jndi:${jettyVersion}")
    compile("jetty-webapp:jetty-webapp:${jettyVersion}")
    compile("jetty-xml:jetty-xml:${jettyVersion}")
    compile("jetty-servlet:jetty-servlet:${jettyVersion}")
    compile("jetty-servlet:jetty-security:${jettyVersion}")
    compile("jetty-servlet:jetty-util:${jettyVersion}")
    compile("jetty-servlet:jetty-server:${jettyVersion}")
    compile("jetty-servlet:jetty-http:${jettyVersion}")
    compile("jetty-servlet:jetty-io:${jettyVersion}")
    compile("jetty-servlet:jetty-schemas:${jettySchemasVersion}")
    compile("apache-jsp:apache-jsp:${jettyVersion}")
    compile("aopalliance:aopalliance:1.0")
    compile("javax.annotation-api:javax.annotation-api:${annotationApiVersion}")
    compile("asm:asm:${asmVersion}")
    compile("asm-tree:asm-tree:${asmVersion}")
    compile("asm-commons:asm-commons:${asmVersion}")    
    compile("jasper-apache-jsp:apache-jsp:${apacheJspVersion}")
    compile("apache-el:apache-el:${apacheJspVersion}")
    compile("ecj:ecj:${ecjVersion}")
    compile("taglibs-standard-spec:taglibs-standard-spec:${taglibsStandardVersion}")
    compile("taglibs-standard-impl:taglibs-standard-impl:${taglibsStandardVersion}")
}

1、jetty9内嵌到应用

 核心类代码如下：

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.List;

import org.apache.tomcat.InstanceManager;
import org.apache.tomcat.SimpleInstanceManager;
import org.eclipse.jetty.annotations.AnnotationConfiguration;
import org.eclipse.jetty.annotations.ClassInheritanceHandler;
import org.eclipse.jetty.annotations.ServletContainerInitializersStarter;
import org.eclipse.jetty.apache.jsp.JettyJasperInitializer;
import org.eclipse.jetty.jsp.JettyJspServlet;
import org.eclipse.jetty.plus.annotation.ContainerInitializer;
import org.eclipse.jetty.server.ConnectionFactory;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.NCSARequestLog;
import org.eclipse.jetty.server.NetworkConnector;
import org.eclipse.jetty.server.RequestLog;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.ServerConnector;
import org.eclipse.jetty.server.handler.HandlerCollection;
import org.eclipse.jetty.server.handler.RequestLogHandler;
import org.eclipse.jetty.server.handler.gzip.GzipHandler;
import org.eclipse.jetty.servlet.DefaultServlet;
import org.eclipse.jetty.servlet.ServletHolder;
import org.eclipse.jetty.util.ConcurrentHashSet;
import org.eclipse.jetty.util.log.JavaUtilLog;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.resource.Resource;
import org.eclipse.jetty.util.thread.QueuedThreadPool;
import org.eclipse.jetty.util.thread.ThreadPool;
import org.eclipse.jetty.webapp.Configuration;
import org.eclipse.jetty.webapp.MetaData;
import org.eclipse.jetty.webapp.WebAppContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.WebApplicationInitializer;

import com.wangzhe.autojoin.wangfw.init.WebAppStrarUpInitializer;
import com.wangzhe.autojoin.wangfw.server.Common;
import com.wangzhe.autojoin.wangfw.server.ServerParam;
import com.wangzhe.autojoin.wangfw.server.jetty9.test.DateServlet;
import com.wangzhe.autojoin.wangfw.util.DateUtil;
import com.wangzhe.autojoin.wangfw.util.ObjectUtil;
import com.wangzhe.autojoin.wangfw.util.Pic2Char;

/**
 * Example of using JSP's with embedded jetty and not requiring all of the
 * overhead of a WebAppContext
 */
public class JettyRunner {
    private static final Logger LOG = LoggerFactory.getLogger(JettyRunner.class);

    // web容器相关参数
    private static final ServerParam param = new ServerParam();

    public static void main(String[] args) throws Exception {
        printFrameWorkLog();
        Common.initServerParam(args, param);
        LoggingUtil.config();
        Log.setLog(new JavaUtilLog());
        JettyRunner main = new JettyRunner();
        main.start();
        printStartSuccess();
        main.waitForInterrupt();
        
    }

    private static void printFrameWorkLog() throws IOException {
        String fileStr = new File("").getAbsolutePath()+"\src\main\webapp\pc\aj.wangfw\img\wang_font.png";
        Pic2Char.startPic2Char(fileStr);
    }
    private static void printStartSuccess() throws IOException {
        String fileStr = new File("").getAbsolutePath()+"\src\main\webapp\pc\aj.wangfw\img\startSuccess.png";
        System.out.println();
        Pic2Char.startPic2Char(fileStr);
    }

    private Server server;
    private URI serverURI;

    public JettyRunner() {
    }

    public URI getServerURI() {
        return serverURI;
    }

    public void start() throws Exception {
        server = new Server(createThreadPool());
        NetworkConnector connector = createConnector();
        server.addConnector(connector);

        URI baseUri = getWebRootResourceUri();
        // Set JSP to use Standard JavaC always
        System.setProperty("org.apache.jasper.compiler.disablejsr199", "false");

        server.setHandler(getWebAppContext(baseUri, getScratchDir()));
        server.addConnector(connector);
        server.setStopAtShutdown(true);
        // Start Server
        server.start();

        // Show server state
        // if (LOG.isDebugEnabled())
        String dump = server.dump();// 输出jetty部分dump信息
        LOG.info(dump.substring(dump.indexOf("> sun.misc.Launcher$AppClassLoader")));
        // }

        this.serverURI = getServerUri(connector);
    }

    private NetworkConnector createConnector() {
        ServerConnector connector = new ServerConnector(server);
        connector.setPort(param.getPort());
        connector.setHost(param.getHost());
        return connector;
    }

    private URI getWebRootResourceUri() throws FileNotFoundException, URISyntaxException {
        URL indexUri = this.getClass().getResource("" + param.getWebDir());
        if (indexUri == null) {
            return null;
        }
        // Points to wherever /webroot/ (the resource) is
        return indexUri.toURI();
    }

    /**
     * Establish Scratch directory for the servlet context (used by JSP
     * compilation)
     */
    private File getScratchDir() throws IOException {
        File tempDir = new File(System.getProperty("java.io.tmpdir"));
        File scratchDir = new File(tempDir.toString(), "embedded-jetty-jsp");

        if (!scratchDir.exists()) {
            if (!scratchDir.mkdirs()) {
                throw new IOException("Unable to create scratch directory: " + scratchDir);
            }
        }
        return scratchDir;
    }

    /**
     * Setup the basic application "context" for this application at "/" This is
     * also known as the handler tree (in jetty speak)
     */
    private HandlerCollection getWebAppContext(URI baseUri, File scratchDir) {
        WebAppContext webappCtx = new WebAppContext();
        webappCtx.setContextPath("/");
        // webappCtx.setDescriptor(param.getWebDir()+"\WEB-INF\web.xml");
        // webappCtx.setWar(param.getWebDir());//for war
        webappCtx.setDisplayName("auto join");
        webappCtx.setTempDirectory(new File(param.getTempDir()));
        webappCtx.setWelcomeFiles(new String[] { param.getWebDir() + "\index.html" });// 欢迎页面
        webappCtx.setConfigurationDiscovered(true);
        webappCtx.setParentLoaderPriority(true);
        RequestLogHandler logHandler = new RequestLogHandler();
        logHandler.setRequestLog(createRequestLog());

        webappCtx.setAttribute("javax.servlet.context.tempdir", scratchDir);
        webappCtx.setAttribute("org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern",
                ".*/[^/]*servlet-api-[^/]*\.jar$|.*/javax.servlet.jsp.jstl-.*\.jar$|.*/.*taglibs.*\.jar$");
        if (ObjectUtil.isNotEmpty(baseUri)) {
            webappCtx.setResourceBase(baseUri.toASCIIString());// for dir
        } else {
            webappCtx.setResourceBase(param.getWebDir());
        }

        webappCtx.setAttribute("org.eclipse.jetty.containerInitializers", jspInitializers());
        webappCtx.setAttribute(InstanceManager.class.getName(), new SimpleInstanceManager());
        webappCtx.addBean(new ServletContainerInitializersStarter(webappCtx), true);
        webappCtx.setClassLoader(getUrlClassLoader());

        webappCtx.addServlet(jspServletHolder(), "*.jsp");
        // Add Application Servlets
        webappCtx.addServlet(DateServlet.class, "/date/");
        webappCtx.addServlet(exampleJspFileMappedServletHolder(), "/test/foo/");
        webappCtx.addServlet(defaultServletHolder(baseUri), "/");
        
        setConfigurations(webappCtx);
        
        MetaData metaData = webappCtx.getMetaData();
        Resource webappInitializer = Resource.newResource(WebAppStrarUpInitializer.class.getProtectionDomain().getCodeSource().getLocation());
        metaData.addContainerResource(webappInitializer);

        HandlerCollection handlerCollection = new HandlerCollection();
        GzipHandler gzipHandler = new GzipHandler();
        handlerCollection.setHandlers(new Handler[] { webappCtx, logHandler, gzipHandler });
        return handlerCollection;
    }

    private void setConfigurations(WebAppContext webappCtx) {
        webappCtx.setConfigurations(new Configuration[] { 
                 new AnnotationConfiguration() {
                        @Override
                        public void preConfigure(WebAppContext context) throws Exception {
                            ClassInheritanceMap map = new ClassInheritanceMap();
                            ConcurrentHashSet<String> hashSet = new  ConcurrentHashSet<String>();
                            hashSet.add(WebAppStrarUpInitializer.class.getName());
                            map.put(WebApplicationInitializer.class.getName(), hashSet);
                            context.setAttribute(CLASS_INHERITANCE_MAP, map);
                            _classInheritanceHandler = new ClassInheritanceHandler(map);
                        }
                    } 
         });
    }

    /**
     * Ensure the jsp engine is initialized correctly
     */
    private List<ContainerInitializer> jspInitializers() {
        JettyJasperInitializer sci = new JettyJasperInitializer();
        ContainerInitializer initializer = new ContainerInitializer(sci, null);
        List<ContainerInitializer> initializers = new ArrayList<ContainerInitializer>();
        initializers.add(initializer);
        return initializers;
    }

    /**
     * Set Classloader of Context to be sane (needed for JSTL) JSP requires a
     * non-System classloader, this simply wraps the embedded System classloader
     * in a way that makes it suitable for JSP to use
     */
    private ClassLoader getUrlClassLoader() {
        ClassLoader jspClassLoader = new URLClassLoader(new URL[0], this.getClass().getClassLoader());
        // jspClassLoader=Thread.currentThread().getContextClassLoader();
        // //也可以用这种方式
        return jspClassLoader;
    }

    /**
     * Create JSP Servlet (must be named "jsp")
     */
    private ServletHolder jspServletHolder() {
        ServletHolder holderJsp = new ServletHolder("jsp", JettyJspServlet.class);
        holderJsp.setInitOrder(0);
        holderJsp.setInitParameter("logVerbosityLevel", "DEBUG");
        holderJsp.setInitParameter("fork", "false");
        holderJsp.setInitParameter("xpoweredBy", "false");
        holderJsp.setInitParameter("compilerTargetVM", "1.7");
        holderJsp.setInitParameter("compilerSourceVM", "1.7");
        holderJsp.setInitParameter("keepgenerated", "true");
        return holderJsp;
    }

    /**
     * Create Example of mapping jsp to path spec
     */
    private ServletHolder exampleJspFileMappedServletHolder() {
        ServletHolder holderAltMapping = new ServletHolder();
        holderAltMapping.setName("foo.jsp");
        holderAltMapping.setForcedPath("/test/foo/foo.jsp");
        return holderAltMapping;
    }

    /**
     * Create Default Servlet (must be named "default")
     */
    private ServletHolder defaultServletHolder(URI baseUri) {
        ServletHolder holderDefault = new ServletHolder("default", DefaultServlet.class);
        if (ObjectUtil.isNotEmpty(baseUri)) {
            LOG.info("Base URI: " + baseUri);
            holderDefault.setInitParameter("resourceBase", baseUri.toASCIIString());
        } else {
            holderDefault.setInitParameter("resourceBase", param.getWebDir());
        }

        holderDefault.setInitParameter("dirAllowed", "true");
        return holderDefault;
    }

    /**
     * Establish the Server URI
     */
    private URI getServerUri(NetworkConnector connector) throws URISyntaxException {
        String scheme = "http";
        for (ConnectionFactory connectFactory : connector.getConnectionFactories()) {
            if (connectFactory.getProtocol().equals("SSL-http")) {
                scheme = "https";
            }
        }
        String host = connector.getHost();
        if (host == null) {
            host = "localhost";
        }
        int port = connector.getLocalPort();
        serverURI = new URI(String.format("%s://%s:%d/", scheme, host, port));
        LOG.info("start sucess on Server URI: " + serverURI);
    
        return serverURI;
    }

    public void stop() throws Exception {
        server.stop();
    }

    /**
     * Cause server to keep running until it receives a Interrupt.
     * <p>
     * Interrupt Signal, or SIGINT (Unix Signal), is typically seen as a result
     * of a kill -TERM {pid} or Ctrl+C
     * 
     * @throws InterruptedException
     *             if interrupted
     */
    public void waitForInterrupt() throws InterruptedException {
        server.join();
    }

    public static ServerParam getParam() {
        return param;
    }

    private RequestLog createRequestLog() {
        // 记录访问日志的处理
        NCSARequestLog requestLog = new NCSARequestLog();
        requestLog.setFilename(param.getLogDir() + "/jetty_log" + DateUtil.formatDate(DateUtil.YYYYMMDD) + ".log");
        requestLog.setRetainDays(90);
        requestLog.setExtended(false);
        requestLog.setAppend(true);
        // requestLog.setLogTimeZone("GMT");
        requestLog.setLogTimeZone("Asia/beijing");
        requestLog.setLogDateFormat("yyyy-MM-dd HH:mm:ss");
        requestLog.setLogLatency(true);
        return requestLog;
    }

    /**
     * 设置线程池
     * 
     * @return
     */
    private ThreadPool createThreadPool() {
        QueuedThreadPool threadPool = new QueuedThreadPool();
        threadPool.setMinThreads(10);
        threadPool.setMaxThreads(500);
        return threadPool;
    }
}

2、jetty9服务器启动时加载WebApplicationInitializer

 下面代码是WebApplicationInitializer的一个实现类

@Order(Integer.MIN_VALUE) // 较低的值有更高的优先级 所以这个类的优先级是最高的
public class WebAppStrarUpInitializer implements WebApplicationInitializer{

    public WebAppStrarUpInitializer() {
        
    }

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        System.out.println("hello WebAppStrarUpInitializer");
        
    }
     
}

 下面代码是从上面第一部分的JettyRunner类中抽取的部分代码，即注册WebApplicationInitializer的地方

 private void setConfigurations(WebAppContext webappCtx) {
        webappCtx.setConfigurations(new Configuration[] { 
                 new AnnotationConfiguration() {
                        @Override
                        public void preConfigure(WebAppContext context) throws Exception {
                            ClassInheritanceMap map = new ClassInheritanceMap();
                            ConcurrentHashSet<String> hashSet = new  ConcurrentHashSet<String>();
                            hashSet.add(WebAppStrarUpInitializer.class.getName());//注册WebApplicationInitializer
                            map.put(WebApplicationInitializer.class.getName(), hashSet);
                            context.setAttribute(CLASS_INHERITANCE_MAP, map);
                            _classInheritanceHandler = new ClassInheritanceHandler(map);
                        }
                    } 
         });
    }

完成代码编写后，请运行JettyRunner类的main方法，运行后请在浏览器输入localhost/index.jsp即可看到效果。如图：

参考：

https://github.com/orb15/embeddedjetty9-spring4

https://github.com/langtianya/embedded-jetty-jsp

https://github.com/yjmyzz/jetty-embed-demo

本文代码托管：https://github.com/langtianya/autojion/tree/master/module_project