java.lang.LinkageError：Grails 项目中的加载程序约束冲突

Question

我用 POI 构建了一个 Grails 项目（包括 poi-3.7 和 poi-ooxml-3.7）。我已将这 2 个外部库添加到项目的 BuildConfig.groovy 文件中的依赖项块中。我编译的时候没有什么奇怪的。但是当我为该项目调用命令“run-app”时，下面的堆栈跟踪发生了错误：

Base Directory: <path-to-my-project>
Resolving dependencies...
Dependencies resolved in 5546ms.
Running script D:\_TOOLS\STS\grails-1.3.5\scripts\RunApp.groovy
Environment set to development
Running Grails application..
2011-05-23 18:51:01,225 [main] ERROR context.GrailsContextLoader  - Error executing bootstraps: java.lang.LinkageError: loader constraint violation: loader (instance of <bootloader>) previously initiated loading for a different type with name "org/w3c/dom/DOMConfiguration"
org.codehaus.groovy.runtime.InvokerInvocationException: java.lang.LinkageError: loader constraint violation: loader (instance of <bootloader>) previously initiated loading for a different type with name "org/w3c/dom/DOMConfiguration"
    at grails.spring.BeanBuilder.invokeBeanDefiningClosure(BeanBuilder.java:723)
    at grails.spring.BeanBuilder.beans(BeanBuilder.java:573)
    at grails.spring.BeanBuilder.invokeMethod(BeanBuilder.java:519)
    at org.grails.tomcat.TomcatServer.start(TomcatServer.groovy:212)
    at grails.web.container.EmbeddableServer$start.call(Unknown Source)
    at RunApp$_run_closure5_closure12.doCall(RunApp:158)
    at RunApp$_run_closure5_closure12.doCall(RunApp)
    at _GrailsSettings_groovy$_run_closure10.doCall(_GrailsSettings_groovy:280)
    at _GrailsSettings_groovy$_run_closure10.call(_GrailsSettings_groovy)
    at RunApp$_run_closure5.doCall(RunApp:149)
    at RunApp$_run_closure5.call(RunApp)
    at RunApp.runInline(RunApp:116)
    at RunApp.this$4$runInline(RunApp)
    at RunApp$_run_closure1.doCall(RunApp:59)
    at RunApp$_run_closure1.doCall(RunApp:33)
    at gant.Gant$_dispatch_closure5.doCall(Gant.groovy:381)
    at gant.Gant$_dispatch_closure7.doCall(Gant.groovy:415)
    at gant.Gant$_dispatch_closure7.doCall(Gant.groovy)
    at gant.Gant.withBuildListeners(Gant.groovy:427)
    at gant.Gant.this$2$withBuildListeners(Gant.groovy)
    at gant.Gant$this$2$withBuildListeners.callCurrent(Unknown Source)
    at gant.Gant.dispatch(Gant.groovy:415)
    at gant.Gant.this$2$dispatch(Gant.groovy)
    at gant.Gant.invokeMethod(Gant.groovy)
    at gant.Gant.executeTargets(Gant.groovy:590)
    at gant.Gant.executeTargets(Gant.groovy:589)

Caused by: java.lang.LinkageError: loader constraint violation: loader (instance of <bootloader>) previously initiated loading for a different type with name "org/w3c/dom/DOMConfiguration"
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2427)
    at java.lang.Class.getDeclaredMethods(Class.java:1791)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.codehaus.groovy.util.LazyReference.getLocked(LazyReference.java:46)
    at org.codehaus.groovy.util.LazyReference.get(LazyReference.java:33)
    at grails.spring.DynamicElementReader.invokeMethod(DynamicElementReader.groovy:121)
    ... 26 more  

这是我的配置：

dependencies {  
        provided ('com.oracle:ojdbc6_g:11.2.0.1.0')  
        runtime ('org.apache.poi:poi:3.7', 'org.apache.poi:poi-ooxml:3.7')  
    }  

我该怎么做才能解决这个问题？非常感谢！

Answer 1

我不知道这是否能解决你的问题，但我猜你对 POI 的依赖可能应该是编译时的。尝试将依赖项更改为：

dependencies {  
    provided ('com.oracle:ojdbc6_g:11.2.0.1.0')  
    compile ('org.apache.poi:poi:3.7', 'org.apache.poi:poi-ooxml:3.7')  
}  

Answer 2

POI 的依赖项之一（xmlbeans）和 grails 之间存在冲突。您可以按如下方式排除它：

dependencies {
    compile('org.apache.poi:poi-ooxml:3.7') { excludes "xmlbeans" }
}

以下链接有助于追踪问题：

• http://markmail.org/message/ojglzgft57ts4dgw
• http://jira.grails.org/browse/MAVEN-22

Answer 3

我遇到了类似的问题，这是一个缓存问题。我删除了 .grails 和 .ivy2 目录（在主目录下），它解决了我的麻烦。祝你好运。

Answer 4

这是我们在来回几个小时后终于解决的问题。简而言之，从 poi 中排除 xmlbeans 并创建另一个 xmlbeans jar 并删除有问题的类。这是驱邪联结错误的咒语。

• 修改 BuildConfig.groovy

    dependencies {
       compile ('org.apache.poi:poi-ooxml:3.6') {excludes "xmlbeans"}
    }

• 提取 xmlbeans

  光盘~
  mkdir xmlbeantmp
  cd xmlbeantmp
  cp ~/.ivy2/cache/org.apache.xmlbeans/xmlbeans/jars/xmlbeans-2.3.0.jar .
  jar xf xmlbeans-2.3.0.jar
  

• 删除违规类包

  cd 组织
  rm -rf w3c/
  

• 重新创建 jar

  cd ../
  rm xmlbean-2.3.0.jar
  jar cf xmlbean-2.3.0.jar *
  

• 将 jar 复制到您的项目库中

  cp xmlbean-2.3.0.jar your_grails_project/lib/.
  

• 表达爱

  点击回答向上箭头。 :)

Answer 5

我想我解决了这个问题。 由于 Perm gen 空间/“grails run-app”期间内存不足，Steve Wall 的解决方案不想在 grails 2.0.0 上为我工作。

BuildConfig.groovy

....
inherits("global") {
    excludes 'xmlbeans', 'xbean'
}
....
runtime 'xmlbeans:xmlpublic:2.1.0'
runtime 'org.apache.poi:poi-ooxml:3.7'
....

然后下载xbean-2.1.0.jar，应用Steve Wall的解决方案：

jar xf xbean-2.1.0.jar
cd org
rm -rf w3c/
cd ..
rm xbean-2.1.0.jar
jar cf xbean-2.1.0.patched.jar *
cp xbean-2.1.0.patched.jar your_grails_project/lib/

对我来说效果很好！祝你好运！