昨天用spring做了个定时器，用于定时扫描某通讯公司外网ftp服务器的约定路径下是否有我需要的文件并下载到本公司服务器上。记得以前做过类似的一个定时器，觉得手到擒来的事情，没想到又折腾了大半天，就是因为spring中commons-attributes-compiler.jar的使用问题。
问题是这样的：扫面和下载程序，触发类和函数，web.xml和spring配置文件，这些准备工作都已经完成，就是在服务器启动的时候报错：
INFO: Deploying web application archive GRCC.war
Sep 14, 2007 13:22:18 AM org.apache.catalina.util.ExtensionValidator validateManifestResources
INFO: ExtensionValidator[/GRCC][commons-attributes-api.jar]: Required extension "ant" not found.
Sep 14, 2007 13:22:18 AM org.apache.catalina.util.ExtensionValidator validateManifestResources
INFO: ExtensionValidator[/GRCC][commons-attributes-compiler.jar]: Required extension "ant" not found.
Sep 14, 2007 13:22:18 AM org.apache.catalina.util.ExtensionValidator validateManifestResources
INFO: ExtensionValidator[/GRCC][commons-attributes-compiler.jar]: Required extension "javadoc" not found.
Sep 14, 2007 13:22:18 AM org.apache.catalina.util.ExtensionValidator validateManifestResources
INFO: ExtensionValidator[/GRCC]: Failure to find 3 required extension(s).
Sep 14, 2007 13:22:18 AM org.apache.catalina.core.StandardContext start
SEVERE: Error getConfigured
Sep 14, 2007 13:22:18 AM org.apache.catalina.core.StandardContext start
SEVERE: Context [/GRCC startup failed due to previous errors
Sep 14, 2007 13:22:18 AM org.apache.catalina.core.StandardContext stop
INFO: Container org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/GRCC] has not been started
Sep 14, 2007 13:22:18 AM org.apache.catalina.util.ExtensionValidator validateManifestResources
INFO: ExtensionValidator[/GRCC][commons-attributes-api.jar]: Required extension "ant" not found.
Sep 14, 2007 13:22:18 AM org.apache.catalina.util.ExtensionValidator validateManifestResources
INFO: ExtensionValidator[/GRCC][commons-attributes-compiler.jar]: Required extension "ant" not found.
Sep 14, 2007 13:22:18 AM org.apache.catalina.util.ExtensionValidator validateManifestResources
INFO: ExtensionValidator[/GRCC][commons-attributes-compiler.jar]: Required extension "javadoc" not found.
Sep 14, 2007 13:22:18 AM org.apache.catalina.util.ExtensionValidator validateManifestResources
INFO: ExtensionValidator[/GRCC]: Failure to find 3 required extension(s).
Sep 14, 2007 13:22:18 AM org.apache.catalina.core.StandardContext start
SEVERE: Error getConfigured
Sep 14, 2007 13:22:18 AM org.apache.catalina.core.StandardContext start
SEVERE: Context [/GRCC startup failed due to previous errors
Sep 14, 2007 13:22:18 AM org.apache.catalina.core.StandardContext stop
INFO: Container org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/GRCC] has not been started
并导致本项目无法启动！
从错误可以看出，commons-attributes-compiler.jar需要的"ant","javadoc","qdox"无法找到，我又检查了数遍，ant和qdox这些jar包我都已经加lib里了，可spring就是视而不见！我郁闷了好久，最后实在不行了，我决定解压commons-attributes-compiler.jar，看看它的庐山真面目，里面还真不复杂：META-INF\MANIFEST.MF,compile\org\apache\commons\attributes\anttasks.properties,LICENSE.txt,,
NOTICE.txt,后两个肯定是说明性的文件，我没有理会；第二个是属性文件，我看格式和注释都没有什么不妥；就MANIFEST.MF里面内容较多，并且有异常之处(我标出了):
Manifest-Version: 1.0
Ant-Version: Apache Ant 1.5.3
Created-By: Apache Maven
Built-By: hen
Package: org.apache.commons.attributes.compiler
Build-Jdk: 1.4.2_05
Extension-Name: commons-attributes-compiler
Specification-Title: Attribute Compiler
Specification-Vendor: The Apache Software Foundation
Implementation-Title: org.apache.commons.attributes.compiler
Implementation-Vendor: The Apache Software Foundation
Implementation-Version: 2.2
Extension-List: ant qdox commons-attributes-api javadoc
ant-Extension-Name: ant
ant-Implementation-Version: 1.5
ant-Implementation-URL: http://www.ibiblio.org/maven/ant/jars/ant-1.
5.jar
qdox-Extension-Name: qdox
qdox-Implementation-Version: 1.5
qdox-Implementation-URL: http://www.ibiblio.org/maven/qdox/jars/qdox-1.
5.jar
commons-attributes-api-Extension-Name: commons-attributes-api
commons-attributes-api-Implementation-Version: 2.2
commons-attributes-api-Implementation-URL: http://www.ibiblio.org/maven/commons-attributes/jars/commons-attributes-api-2.2
.jar
javadoc-Extension-Name: javadoc
javadoc-Implementation-Version: 1.4
javadoc-Implementation-URL: http://www.ibiblio.org/maven/javadoc/jars/javadoc-1.4
.jar
Implementation-Vendor-Id: org.apache
X-Compile-Source-JDK: 1.4
X-Compile-Target-JDK: 1.4
这里的URL后面的值被换行符隔开了，显然，如果让我们自己，是不会这么干的。于是，做修改如下：
Manifest-Version: 1.0
Ant-Version: Apache Ant 1.5.3
Created-By: Apache Maven
Built-By: hen
Package: org.apache.commons.attributes.compiler
Build-Jdk: 1.4.2_05
Extension-Name: commons-attributes-compiler
Specification-Title: Attribute Compiler
Specification-Vendor: The Apache Software Foundation
Implementation-Title: org.apache.commons.attributes.compiler
Implementation-Vendor: The Apache Software Foundation
Implementation-Version: 2.2
Extension-List: ant qdox commons-attributes-api javadoc
ant-Extension-Name: ant
ant-Implementation-Version: 1.5
ant-Implementation-URL: http://www.ibiblio.org/maven/ant/jars/ant-1.5.jar
qdox-Extension-Name: qdox
qdox-Implementation-Version: 1.5
qdox-Implementation-URL: http://www.ibiblio.org/maven/qdox/jars/qdox-1.5.jar
commons-attributes-api-Extension-Name: commons-attributes-api
commons-attributes-api-Implementation-Version: 2.2
commons-attributes-api-Implementation-URL: http://www.ibiblio.org/maven/commons-attributes/jars/commons-attributes-api-2.2.jar
javadoc-Extension-Name: javadoc
javadoc-Implementation-Version: 1.4
javadoc-Implementation-URL: http://www.ibiblio.org/maven/javadoc/jars/javadoc-1.4.jar
Implementation-Vendor-Id: org.apache
X-Compile-Source-JDK: 1.4
X-Compile-Target-JDK: 1.4
重新打成jar包，添加到项目lib中，启动运行，一切OK！
可是，以前写定时器也没遇到这种情况啊，我想这跟spring的版本有关系吧；今天用的spring2.0，可是谁把MANIFEST.MF中的URL弄错的呢？我想不应该是官方的bug吧，可能是我不是在官网上下的spring开发包，有机会看看官网上是否也是这个样子。不管怎么说，项目还是在波澜不惊中顺利进行。。。
本文转自NightWolves 51CTO博客，原文链接：
http://blog.51cto.com/yangfei520/403521
，如需转载请自行联系原作者
