安装Vaadin后获得NoClassDefFoundError [英] Getting a NoClassDefFoundError after installing Vaadin
问题描述
我下载了Eclipse并安装了Vaadin for Eclipse插件。然后，我创建了一个新的Vaadin 7项目。它下载了一些常春藤依赖关系，但是当我按下Run时，我得到这个错误：java.lang.NoClassDefFoundError：com / vaadin / server / VaadinServlet。
位于互联网上，但无济于事。有一点是，在网络应用程序的WEB-INF / lib文件夹中，没有jar。我附上了错误的屏幕截图以及web.xml和ivy.xml。
ivy.xml：
<？xml version =1.0？>
<！DOCTYPE ivy-module [
<！ENTITY vaadin.version7.1.7>
]>
< ivy-module version =2.0
xmlns：xsi =http://www.w3.org/2001/XMLSchema-instance
xsi：noNamespaceSchemaLocation = http://ant.apache.org/ivy/schemas/ivy.xsd >
< info organization =com.examplemodule =v7proj/>
<配置>
<！ - 应该部署到服务器的默认配置 - >
< conf name =default/>
<！ - 仅在编译窗口小部件集时才需要配置。如果
未被部署到服务器 - >
< conf name =widgetset-compile/>
<！ - 仅用于编译服务器端类的配置。
应该部署到服务器 - >
< conf name =nodeploy/>
< / configurations>
< dependencies defaultconf =defaultdefaultconfmapping =default-> default>
<！ - Vaadin的核心服务器部分 - >
< dependency org =com.vaadinname =vaadin-serverrev =& vaadin.version; />
<！ - Vaadin主题 - >
< dependency org =com.vaadinname =vaadin-themesrev =& vaadin.version; />
<！ - 推送支持 - >
< dependency org =com.vaadinname =vaadin-pushrev =& vaadin.version; />
<！ - Servlet 3.0 API - >
< dependency org =javax.servletname =javax.servlet-apirev =3.0.1conf =nodeploy-> default/>
<！ - 预编译的DefaultWidgetSet - >
< dependency org =com.vaadinname =vaadin-client-compiled
rev =& vaadin.version; />
<！ - Vaadin客户端，小部件集编译所需 - >
< dependency org =com.vaadinname =vaadin-clientrev =& vaadin.version;
conf =widgetset-compile-> default/>
<！ - 自定义窗口小部件集的编译器。不应该部署 - >
< dependency org =com.vaadinname =vaadin-client-compiler
rev =& vaadin.version; conf =widgetset-compile-> default/>
< / dependencies>
< / ivy-module>
ivysettings.xml：
<？xml version =1.0encoding =UTF-8？>
< ivysettings>
< settings defaultResolver =default/>
< resolvers>
< chain name =default>
<！ - 公共Maven仓库 - >
< ibiblio name =publicm2compatible =true/>
<！ - Vaadin附加存储库 - >
< ibiblio name =vaadin-addonsusepoms =truem2compatible =true
root =http://maven.vaadin.com/vaadin-addons/>
<！ - Vaadin快照库 - >
< ibiblio name =vaadin-snapshotsusepoms =truem2compatible =true
root =https://oss.sonatype.org/content/repositories/vaadin-snapshots/ >
<！ - 用于Vaadin修改的smartsprites库的存储库 - >
< dual name =custom-smartsprites>
< filesystem name =smartsprites-ivy>
< ivy pattern =$ {basedir} / ivymodule / [module] -ivy- [revision] .xml/>
< / filesystem>
< url name =smartsprites-artifact>
< artifact
pattern =http://dev.vaadin.com/svn/versions/6.8/build/smartsprites/lib/[artifact](-[revision]).[ext] />
< / url>
< / dual>
< / chain>
< / resolvers>
< modules>
<！ - Vaadin打补丁SmartSprites - >
< module organization =com.carrotsearchname =smartsprites
revision =0.2.3-itmillresolver =custom-smartsprites/>
< / modules>
< / ivysettings>
web.xml：
<？xml version =1.0encoding =UTF-8？>
< web-app xmlns：xsi =http://www.w3.org/2001/XMLSchema-instancexmlns =http://java.sun.com/xml/ns/javaeexsi ：schemaLocation =http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsdid =WebApp_IDversion =3.0 >
< display-name> ScanAir< / display-name>
< welcome-file-list>
< welcome-file> index.html< / welcome-file>
< welcome-file> index.htm< / welcome-file>
< welcome-file> index.jsp< / welcome-file>
< welcome-file> default.html< / welcome-file>
< welcome-file> default.htm< / welcome-file>
< welcome-file> default.jsp< / welcome-file>
< / welcome-file-list>
< / web-app>
请帮忙。我基本上没有开始代码就被卡住了。我在Windows 8.1 Pro x64与Java 7u45，Eclipse Kepler SR1和Vaadin 7.1.7
在stackoverflow有很多问题以及关于这个错误例外的更多答案。
看看这个好网页： http://javareferencegv.blogspot.ch/2013/10/debugging-javalangnoclassdeffounderror.html
有一点是，在网络应用程序的WEB-INF / lib文件夹中，没有
jar。
这是一个很好的开始。
在eclipse中查看你的项目属性。有一个点叫部署程序集，它至少应包含这两个条目：
/ src - > WEB-INF / classes
/ WebContent - > /
此外，您必须将您的项目添加到tomcat服务器实例。
I want to do a project using Vaadin and am facing some issues. Here's what I did.
I downloaded Eclipse and installed the Vaadin for Eclipse plugin. Then, I created a new Vaadin 7 project. It downloaded some Ivy dependencies but then, when I pressed Run, I get this error: java.lang.NoClassDefFoundError:com/vaadin/server/VaadinServlet.
I searched a bit on the Internet but to no avail. One thing is that in the web-app's WEB-INF/lib folder, there are no jars. I have attached a screenshot of the error and also web.xml and ivy.xml.
ivy.xml:
<?xml version="1.0"?>
<!DOCTYPE ivy-module [
<!ENTITY vaadin.version "7.1.7">
]>
<ivy-module version="2.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="http://ant.apache.org/ivy/schemas/ivy.xsd">
<info organisation="com.example" module="v7proj" />
<configurations>
<!-- The default configuration, which should be deployed to the server -->
<conf name="default" />
<!-- A configuration only needed when compiling the widget set. Should
not be deployed to the server -->
<conf name="widgetset-compile" />
<!-- A configuration used in compilation of server side classes only.
Should be deployed to the server -->
<conf name="nodeploy" />
</configurations>
<dependencies defaultconf="default" defaultconfmapping="default->default">
<!-- The core server part of Vaadin -->
<dependency org="com.vaadin" name="vaadin-server" rev="&vaadin.version;" />
<!-- Vaadin themes -->
<dependency org="com.vaadin" name="vaadin-themes" rev="&vaadin.version;" />
<!-- Push support -->
<dependency org="com.vaadin" name="vaadin-push" rev="&vaadin.version;" />
<!-- Servlet 3.0 API -->
<dependency org="javax.servlet" name="javax.servlet-api" rev="3.0.1" conf="nodeploy->default" />
<!-- Precompiled DefaultWidgetSet -->
<dependency org="com.vaadin" name="vaadin-client-compiled"
rev="&vaadin.version;" />
<!-- Vaadin client side, needed for widget set compilation -->
<dependency org="com.vaadin" name="vaadin-client" rev="&vaadin.version;"
conf="widgetset-compile->default" />
<!-- Compiler for custom widget sets. Should not be deployed -->
<dependency org="com.vaadin" name="vaadin-client-compiler"
rev="&vaadin.version;" conf="widgetset-compile->default" />
</dependencies>
</ivy-module>
ivysettings.xml:
<?xml version="1.0" encoding="UTF-8"?>
<ivysettings>
<settings defaultResolver="default" />
<resolvers>
<chain name="default">
<!-- Public Maven repository -->
<ibiblio name="public" m2compatible="true" />
<!-- Vaadin Add-on repository -->
<ibiblio name="vaadin-addons" usepoms="true" m2compatible="true"
root="http://maven.vaadin.com/vaadin-addons" />
<!-- Vaadin snapshots repository -->
<ibiblio name="vaadin-snapshots" usepoms="true" m2compatible="true"
root="https://oss.sonatype.org/content/repositories/vaadin-snapshots" />
<!-- Repository used for Vaadin modified smartsprites library -->
<dual name="custom-smartsprites">
<filesystem name="smartsprites-ivy">
<ivy pattern="${basedir}/ivymodule/[module]-ivy-[revision].xml" />
</filesystem>
<url name="smartsprites-artifact">
<artifact
pattern="http://dev.vaadin.com/svn/versions/6.8/build/smartsprites/lib/[artifact](-[revision]).[ext]" />
</url>
</dual>
</chain>
</resolvers>
<modules>
<!-- Vaadin patched SmartSprites -->
<module organisation="com.carrotsearch" name="smartsprites"
revision="0.2.3-itmill" resolver="custom-smartsprites" />
</modules>
</ivysettings>
web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>ScanAir</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>
Please help. I am basically stuck without even starting to code. I am on Windows 8.1 Pro x64 with Java 7u45, Eclipse Kepler SR1 and Vaadin 7.1.7
On stackoverflow there are many questions and more answers about this error exception.
Have a look at this good webpage: http://javareferencegv.blogspot.ch/2013/10/debugging-javalangnoclassdeffounderror.html
One thing is that in the web-app's WEB-INF/lib folder, there are no jars.
This is a good point to start.
In eclipse have a look at your project properties. There is a point called "Deployment Assembly" which should contain at least these two entries:
/src -> WEB-INF/classes
/WebContent -> /
Moreover you must add your project to the tomcat server instance.
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