那些遇到过的问题

如何使用Eclipse为Jetty编写简单的Servlet？

Jon*_*nas 10 java eclipse servlets jetty war

我下载了Eclipse for Java EE和Jetty 8.1,并希望实现一个非常简单的Servlet.

Jetty在我开始使用时工作正常java -jar start.jar.

为了开发Servlet,我做了这个:

  1. 在Eclipse中,我选择了"New Dynamic Web Project".

  2. 我jetty\lib\servlet-api-3.0.jar在Eclipse中添加了"Build Path".

  3. 在该项目中,生成了"New Servlet"和Servlet,并添加了一些代码:

    /**
 * Servlet implementation class MyServlet
 */
@WebServlet("/MyServlet")
public class MyServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, 
                HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, 
                HttpServletResponse response)
        throws ServletException, IOException {
        PrintWriter out = response.getWriter();
        out.println("<html><body><h1>My Servlet</h1></body></html>");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, 
                HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, 
                HttpServletResponse response)
        throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}
    Run Code Online (Sandbox Code Playgroud)

  4. 我创建了一个文件,web.xml在WebContent\WEB-INF\web.xml这个内容:

    <?xml version="1.0" encoding="utf-8" ?>
<web-app 
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
<servlet>
    <servlet-name>My Servlet</servlet-name>
<servlet-class>MyServlet.class</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>My Servlet</servlet-name>
    <url-pattern>/Servlet</url-pattern>
</servlet-mapping>
    Run Code Online (Sandbox Code Playgroud)

  5. 我将已编译的.class文件复制build\classes到了WebContent\WEB-INF\classes

  6. 现在我选择将项目导出为.war-file到jetty\webapps\MySite.war.

  7. 我启动Jetty java -jar start.jar并访问localhost:8080/MySite/Servlet但现在我收到此消息:

    Servlet Not Initialized

javax.servlet.UnavailableException: Servlet Not Initialized
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:546)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:485)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:483)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:233)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1065)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:412)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:192)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:999)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:250)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:149)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:111)
at org.eclipse.jetty.server.Server.handle(Server.java:351)
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:451)
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:916)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:647)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:233)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:76)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:615)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:45)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:599)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:534)
at java.lang.Thread.run(Thread.java:722)
    Run Code Online (Sandbox Code Playgroud)

如果我访问localhost:8080/MySite/我看到两个文件夹WEB-INF\,META-INF\都有大小0 bytes.

所以它看起来不像我.war的Eclipse中的-export工作.

如何使用Eclipse导出我的简单Servlet for Jetty？

我现在已经为Eclipse 安装了Jetty WTP插件,但是我无法使用它来运行这个servlet:

2012-01-30 10:06:50.322:INFO:oejs.Server:jetty-8.1.0.RC4
2012-01-30 10:06:50.353:INFO:oejdp.ScanningAppProvider:Deployment monitor C:\Users\Jonas\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\webapps at interval 1
2012-01-30 10:06:50.353:INFO:oejdp.ScanningAppProvider:Deployment monitor C:\Users\Jonas\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\contexts at interval 1
2012-01-30 10:06:50.353:INFO:oejd.DeploymentManager:Deployable added: C:\Users\Jonas\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\contexts\MySite.xml
2012-01-30 10:06:50.650:WARN:oejuc.AbstractLifeCycle:FAILED o.e.j.w.WebAppContext{/MySite,file:/C:/Users/Jonas/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/MySite/},C:\Users\Jonas\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0/wtpwebapps/MySite: java.lang.NoClassDefFoundError: org/objectweb/asm/ClassVisitor
java.lang.NoClassDefFoundError: org/objectweb/asm/ClassVisitor
    at org.eclipse.jetty.annotations.AnnotationConfiguration.createAnnotationParser(AnnotationConfiguration.java:111)
    at org.eclipse.jetty.annotations.AnnotationConfiguration.configure(AnnotationConfiguration.java:73)
    at org.eclipse.jetty.webapp.WebAppContext.configure(WebAppContext.java:428)
    at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1208)
    at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:699)
    at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:454)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
    at org.eclipse.jetty.deploy.bindings.StandardStarter.processBinding(StandardStarter.java:36)
    at org.eclipse.jetty.deploy.AppLifeCycle.runBindings(AppLifeCycle.java:183)
    at org.eclipse.jetty.deploy.DeploymentManager.requestAppGoal(DeploymentManager.java:491)
    at org.eclipse.jetty.deploy.DeploymentManager.addApp(DeploymentManager.java:138)
    at org.eclipse.jetty.deploy.providers.ScanningAppProvider.fileAdded(ScanningAppProvider.java:142)
    at org.eclipse.jetty.deploy.providers.ScanningAppProvider$1.fileAdded(ScanningAppProvider.java:53)
    at org.eclipse.jetty.util.Scanner.reportAddition(Scanner.java:604)
    at org.eclipse.jetty.util.Scanner.reportDifferences(Scanner.java:535)
    at org.eclipse.jetty.util.Scanner.scan(Scanner.java:398)
    at org.eclipse.jetty.util.Scanner.doStart(Scanner.java:332)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
    at org.eclipse.jetty.deploy.providers.ScanningAppProvider.doStart(ScanningAppProvider.java:118)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
    at org.eclipse.jetty.deploy.DeploymentManager.startAppProvider(DeploymentManager.java:552)
    at org.eclipse.jetty.deploy.DeploymentManager.doStart(DeploymentManager.java:227)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
    at org.eclipse.jetty.util.component.AggregateLifeCycle.doStart(AggregateLifeCycle.java:58)
    at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:53)
    at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:91)
    at org.eclipse.jetty.server.Server.doStart(Server.java:263)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
    at org.eclipse.jetty.xml.XmlConfiguration$1.run(XmlConfiguration.java:1214)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.jetty.xml.XmlConfiguration.main(XmlConfiguration.java:1137)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.eclipse.jetty.start.Main.invokeMain(Main.java:457)
    at org.eclipse.jetty.start.Main.start(Main.java:600)
    at org.eclipse.jetty.start.Main.main(Main.java:82)
Caused by: 
java.lang.ClassNotFoundException: org.objectweb.asm.ClassVisitor
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at org.eclipse.jetty.annotations.AnnotationConfiguration.createAnnotationParser(AnnotationConfiguration.java:111)
    at org.eclipse.jetty.annotations.AnnotationConfiguration.configure(AnnotationConfiguration.java:73)
    at org.eclipse.jetty.webapp.WebAppContext.configure(WebAppContext.java:428)
    at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1208)
    at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:699)
    at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:454)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
    at org.eclipse.jetty.deploy.bindings.StandardStarter.processBinding(StandardStarter.java:36)
    at org.eclipse.jetty.deploy.AppLifeCycle.runBindings(AppLifeCycle.java:183)
    at org.eclipse.jetty.deploy.DeploymentManager.requestAppGoal(DeploymentManager.java:491)
    at org.eclipse.jetty.deploy.DeploymentManager.addApp(DeploymentManager.java:138)
    at org.eclipse.jetty.deploy.providers.ScanningAppProvider.fileAdded(ScanningAppProvider.java:142)
    at org.eclipse.jetty.deploy.providers.ScanningAppProvider$1.fileAdded(ScanningAppProvider.java:53)
    at org.eclipse.jetty.util.Scanner.reportAddition(Scanner.java:604)
    at org.eclipse.jetty.util.Scanner.reportDifferences(Scanner.java:535)
    at org.eclipse.jetty.util.Scanner.scan(Scanner.java:398)
    at org.eclipse.jetty.util.Scanner.doStart(Scanner.java:332)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
    at org.eclipse.jetty.deploy.providers.ScanningAppProvider.doStart(ScanningAppProvider.java:118)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
    at org.eclipse.jetty.deploy.DeploymentManager.startAppProvider(DeploymentManager.java:552)
    at org.eclipse.jetty.deploy.DeploymentManager.doStart(DeploymentManager.java:227)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
    at org.eclipse.jetty.util.component.AggregateLifeCycle.doStart(AggregateLifeCycle.java:58)
    at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:53)
    at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:91)
    at org.eclipse.jetty.server.Server.doStart(Server.java:263)
    at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59)
    at org.eclipse.jetty.xml.XmlConfiguration$1.run(XmlConfiguration.java:1214)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.jetty.xml.XmlConfiguration.main(XmlConfiguration.java:1137)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.eclipse.jetty.start.Main.invokeMain(Main.java:457)
    at org.eclipse.jetty.start.Main.start(Main.java:600)
    at org.eclipse.jetty.start.Main.main(Main.java:82)
Run Code Online (Sandbox Code Playgroud)

Don*_*Kim 8

首先,你的web.xml是错误的.

servlet-class元素包含servlet的完全限定类名.

从web.xml架构中,您在第923行使用了http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd.因此,第9行的servlet-class元素的内容应该是MyServlet,而不是MyServlet.class.

其次,只使用一种方法来注册servlet,过滤器或监听器以使其清晰.如果您更喜欢使用注释将它们注册到servlet容器.你最好删除web.xml中的servlet和servlet-mapping元素.否则,您最好删除java源代码中的注释.如果要使用web.xml,则应将架构版本从2.4更新到3.0

最后,您的第二个问题来自Jetty WTP Eclipse插件可以通过尝试这个来解决:websockets项目的jetty运行错误

归档时间：

查看次数：

26212 次

最近记录：

14 年，1 月 前
相关归档
如何使用Eclipse获取模拟器截图？ 174
方法签名中的Java"params"？ 107
移动和消失代码行; Eclipse的XML编辑器出了问题 94
从超类中获取子类的名称 70
是否可以在Kafka 0.8.2中为现有主题添加分区 48
web.xml中与Servlet 3.0兼容的web-app声明有什么作用？ 11
如何使自定义404页面成为转发,而不是Tomcat中的重定向 10
如何在eclipse中配置ADT插件 10
使用Eclipse CDT和GDB进行调试:找不到源文件 9
以编程方式生成BPEL文件？ 7
难疑归档
如何删除远程标签？ 3121
如何在Web表单字段/输入标记上禁用浏览器自动完成？ 2680
如何让Git忽略文件模式(chmod)的变化？ 2188
自制安装特定版本的公式？ 2072
按值复制数组 1638
<button>与<input type ="button"/>.哪个用？ 1588
传输安全性阻止了明文HTTP 1425
我应该如何道德地接近用户密码存储以便以后的明文检索？ 1346
除了XHTML自包含标记之外,RegEx匹配开放标记 1323
将项目导入Eclipse后,"必须覆盖超类方法"错误 1223