您没有以适合 JSP 使用的方式初始化和设置环境。
这需要大量额外的工作。
您需要操作类加载器，设置一些初始化程序，声明 javac 实现行为，甚至声明 jsp servlet 处理。 （缺少其中任何一个，您将受制于您执行的环境，这在您的 3 个示例中有所不同）
有关完整的 maven 项目示例，请参阅https://github.com/jetty-project/embedded-jetty-jsp
public class Main
{
// Resource path pointing to where the WEBROOT is
private static final String WEBROOT_INDEX = "/webroot/";
public static void main(String[] args) throws Exception
{
int port = 8080;
LoggingUtil.config();
Log.setLog(new JavaUtilLog());
Main main = new Main(port);
main.start();
main.waitForInterrupt();
}
private static final Logger LOG = Logger.getLogger(Main.class.getName());
private int port;
private Server server;
private URI serverURI;
public Main(int port)
{
this.port = port;
}
public URI getServerURI()
{
return serverURI;
}
public void start() throws Exception
{
server = new Server();
ServerConnector connector = new ServerConnector(server);
connector.setPort(port);
server.addConnector(connector);
URL indexUri = this.getClass().getResource(WEBROOT_INDEX);
if (indexUri == null)
{
throw new FileNotFoundException("Unable to find resource " + WEBROOT_INDEX);
}
// Points to wherever /webroot/ (the resource) is
URI baseUri = indexUri.toURI();
// Establish Scratch directory for the servlet context (used by JSP compilation)
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);
}
}
// Set JSP to use Standard JavaC always
System.setProperty("org.apache.jasper.compiler.disablejsr199","false");
// Setup the basic application "context" for this application at "/"
// This is also known as the handler tree (in jetty speak)
WebAppContext context = new WebAppContext();
context.setContextPath("/");
context.setAttribute("javax.servlet.context.tempdir",scratchDir);
context.setResourceBase(baseUri.toASCIIString());
context.setAttribute(InstanceManager.class.getName(), new SimpleInstanceManager());
server.setHandler(context);
// Add Application Servlets
context.addServlet(DateServlet.class,"/date/");
//Ensure the jsp engine is initialized correctly
JettyJasperInitializer sci = new JettyJasperInitializer();
ServletContainerInitializersStarter sciStarter = new ServletContainerInitializersStarter(context);
ContainerInitializer initializer = new ContainerInitializer(sci, null);
List<ContainerInitializer> initializers = new ArrayList<ContainerInitializer>();
initializers.add(initializer);
context.setAttribute("org.eclipse.jetty.containerInitializers", initializers);
context.addBean(sciStarter, true);
// 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
ClassLoader jspClassLoader = new URLClassLoader(new URL[0], this.getClass().getClassLoader());
context.setClassLoader(jspClassLoader);
// Add JSP Servlet (must be named "jsp")
ServletHolder holderJsp = new ServletHolder("jsp",JspServlet.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");
context.addServlet(holderJsp,"*.jsp");
//context.addServlet(holderJsp,"*.jspf");
//context.addServlet(holderJsp,"*.jspx");
// Add Example of mapping jsp to path spec
ServletHolder holderAltMapping = new ServletHolder("foo.jsp", JspServlet.class);
holderAltMapping.setForcedPath("/test/foo/foo.jsp");
context.addServlet(holderAltMapping,"/test/foo/");
// Add Default Servlet (must be named "default")
ServletHolder holderDefault = new ServletHolder("default",DefaultServlet.class);
LOG.info("Base URI: " + baseUri);
holderDefault.setInitParameter("resourceBase",baseUri.toASCIIString());
holderDefault.setInitParameter("dirAllowed","true");
context.addServlet(holderDefault,"/");
// Start Server
server.start();
// Show server state
if (LOG.isLoggable(Level.FINE))
{
LOG.fine(server.dump());
}
// Establish the Server URI
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("Server URI: " + 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
*/
public void waitForInterrupt() throws InterruptedException
{
server.join();
}
}