小编erm*_*410的帖子

使用JSContextfrom a a UIWebView创建了一个作为Objective C块实现的javascript函数:

JSContext *js = ... //get contect from web view
js[@"aFunc"] = ^(JSValue *aString, JSValue *callback) {
    NSString *realString = [aString toString];
    MyOperation *op = [[MyOperation alloc] initWithString:realString andCallback:callback];

    //Do some heavy lifting in background
    [self.myQueue addOperation:op];
}

此函数将回调作为参数,并NSOperationQueue在调用回调之前执行一些工作,如:

- (void)main {
    JSValue *arg = [self theHeavyWork];
    //Now we have finished the heavy work, switch back to main thread to run callback (if any).
    if ([self.callback isObject] != NO) {
        dispatch_async(dispatch_get_main_queue(), …

我在Ubuntu 13.04上在jetty上运行servlet时遇到问题.服务器使用apt-get并开始使用安装sudo service jetty start.该应用程序需要该类,org.eclipse.jetty.util.component.AbstractLifeCycle但我得到一个类未找到错误.这是堆栈跟踪:

java.lang.NoClassDefFoundError: org/eclipse/jetty/util/component/AbstractLifeCycle
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:788)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:447)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:420)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:382)
at org.cometd.server.CometdServlet.newBayeuxServer(CometdServlet.java:130)
at org.cometd.server.CometdServlet.init(CometdServlet.java:64)
at org.cometd.annotation.AnnotationCometdServlet.init(AnnotationCometdServlet.java:54)
at javax.servlet.GenericServlet.init(GenericServlet.java:244)
at org.eclipse.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:542)
at org.eclipse.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:424)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:671)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:505)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:138)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:564)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:213)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1094)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:432)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:175)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1028)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:136)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:258)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:109)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
at org.eclipse.jetty.server.Server.handle(Server.java:445)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:267)
at …