使用Eclipse和maven调用异步java servlet时出错

Question

我使用Eclipse IDE来处理servlet。我创建了一个maven项目来使用异步Servlet3.0，并为其添加了适当的依赖关系。代码request.isasyncsupported()返回true。现在，当我调用servlet时，它会给出以下错误

warn:oejs.servletHandler://testplugin/jsonServlet java.lang.IllegalStateException：dependated,初始地址为org.eclipse.jetty.server.request.getAsyncContext(request.java:325),地址为com.ajitpals.search.grid.fs.jsonServlet.doget(jsonServlet.java:42),地址为javax.servlet.http.httpservlet.service(httpservlet.java:734),地址为.servlet.servlethandler.doHandle(servlethandler.java:486)，在org.eclipse.jetty.server.handler.scopedhandler.handle（scopedhandler.java:119)，在org.eclipse.jetty.security.security.security.handler.handle（securityhandler.jandle（securityhandler.java:524)，在org.eclipse.jetty.session.sessionhandler.java:233)，在在org.eclipse.jetty.server.session.sessionHandler.doscope（SessionHandler.java:192)在org.eclipse.jetty.server.handler.contextHandler.doscope（contextHandler.java:999)在org.eclipse.jetty.server.scopedHandler.handler(scopedHandler.java:117)在org.eclipse.jetty.handler.handler.handler(scopedHandler.java:117)在headerComplet(AbstractHttpConnection.890)在org.eclipse.jetty.server.AbstractHttpConnection$requesthandler.headerComplet(AbstractHttpConnection.java:944)在org.eclipse.jetty.http.httpparser.parsenext(httpparser.java:634)在org.eclipse.jetty.http.httpparser.parseAvailable(httpparser.java:230)在elendpoint.handle(SelectChannelendpoint.java:609)位于org.eclipse.jetty.io.nio.selectChannelendpoint$1(selectChannelEndpoint.java:45)在org.eclipse.jetty.util.thread.queuedThreadPool.runjob（queuedThreadPool.java:599)在org.eclipse.jetty.util.thread.queuedThreadPool.java:3.run（queuedThreadPool.java:534)在java.lang.thread.run（来源未知）。

我在maven项目中添加了以下依赖项。

 <dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>3.1-b08</version>
</dependency>

<dependency>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-server</artifactId>
    <version>9.0.2.v20130417</version>
</dependency>

servlet代码是

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    if(request.isAsyncSupported()){

    final AsyncContext asynCtx = request.getAsyncContext();

    //Set the timeout
    asynCtx.setTimeout(35000);

    //Add the listeners.
    asynCtx.addListener(new AsyncListener() {

        public void onTimeout(AsyncEvent arg0) throws IOException {
            System.out.println("timeout");              
        }

        public void onStartAsync(AsyncEvent arg0) throws IOException {
            System.out.println("on start");             
        }

        public void onError(AsyncEvent arg0) throws IOException {
            System.err.println("on error");             
        }

        public void onComplete(AsyncEvent arg0) throws IOException {
            System.out.println("On complete");              
        }
    });

    //start the new thread.
    asynCtx.start(new Runnable() {

        public void run() {
            try{
                asynCtx.getResponse().getWriter().write(MessageFormat.format("<h1>Process task id : [{0}] and Name [{1}]</h1>", 
                        Thread.currentThread().getId()));
            }catch(Exception ex){
                System.err.println("async error " + ex.getMessage());
            }
        }
    });
    }
}

有人面临类似的问题吗？我们如何解决他们。

PWC6345: There is an error in invoking javac. A full JDK (not just JRE) is required Caused by:org.apache.jasper.JasperException:PWC6345: There is an error in invoking javac. A full JDK (not just JRE) is required

Answer 1

这是代码错误，如果我们试图在request.startAsync()之前获取getAsyncrequest()将生成错误。