我收到错误
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/xerces/util/XMLChar
at org.apache.jena.shared.impl.PrefixMappingImpl.checkLegal(PrefixMappingImpl.java:172)
当运行一个简单的Jena示例时，但是我的Maven
pom.xml文件中确实有这两个依赖项：<dependency>
<groupId>org.apache.jena</groupId>
<artifactId>apache-jena-libs</artifactId>
<type>pom</type>
<version>3.6.0</version>
</dependency>
<dependency>
<groupId>xerces</groupId>
<artifactId>xercesImpl</artifactId>
<version>2.11.0</version>
</dependency>
我检查了可下载的Jena存档，并且其
lib目录的确包含Xerces 2.11.0 jar文件，因此版本正确。这里缺少什么？
更新：
AndyS指出不需要依赖，并且
NoClassDefFoundError与更常见的ClassNotFoundException不同。发生错误时没有依赖项。至于
NoClassDefFoundError，不确定是什么原因引起的。我的代码非常简单：String filename = "test.jsonld";
Model model = ModelFactory.createDefaultModel() ;
model.read(filename) ;
test.jsonld被{
"@id": "http://store.example.com/",
"@type": "Store",
"name": "Links Bike Shop",
"description": "The most \"linked\" bike store on earth!"
}
包括异常的完整输出如下。我不确定如何开始对此进行故障排除，有什么建议吗？
12:46:26,102 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Could NOT find resource [logback.groovy]
12:46:26,102 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Could NOT find resource [logback-test.xml]
12:46:26,102 |-INFO in ch.qos.logback.classic.LoggerContext[default] - Found resource [logback.xml] at [file:/C:/Users/E26638/git/aic-praise/target/classes/logback.xml]
12:46:26,103 |-WARN in ch.qos.logback.classic.LoggerContext[default] - Resource [logback.xml] occurs multiple times on the classpath.
12:46:26,104 |-WARN in ch.qos.logback.classic.LoggerContext[default] - Resource [logback.xml] occurs at [file:/C:/Users/E26638/git/aic-expresso/target/classes/logback.xml]
12:46:26,104 |-WARN in ch.qos.logback.classic.LoggerContext[default] - Resource [logback.xml] occurs at [file:/C:/Users/E26638/git/aic-praise/target/classes/logback.xml]
12:46:26,159 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationAction - debug attribute not set
12:46:26,176 |-INFO in ch.qos.logback.core.joran.action.ConversionRuleAction - registering conversion word logxtracemsg with class [com.sri.ai.util.log.LogXTraceConverter]
12:46:26,176 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - About to instantiate appender of type [ch.qos.logback.core.ConsoleAppender]
12:46:26,189 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - Naming appender as [stdout]
12:46:26,251 |-INFO in ch.qos.logback.classic.joran.action.LoggerAction - Setting additivity of logger [com.sri.ai.grinder.helper.Trace] to false
12:46:26,252 |-INFO in ch.qos.logback.classic.joran.action.LevelAction - com.sri.ai.grinder.helper.Trace level set to TRACE
12:46:26,252 |-INFO in ch.qos.logback.classic.joran.action.LoggerAction - Setting additivity of logger [com.sri.ai.grinder.helper.Justification] to false
12:46:26,252 |-INFO in ch.qos.logback.classic.joran.action.LevelAction - com.sri.ai.grinder.helper.Justification level set to TRACE
12:46:26,252 |-INFO in ch.qos.logback.classic.joran.action.LevelAction - ROOT level set to DEBUG
12:46:26,252 |-INFO in ch.qos.logback.core.joran.action.AppenderRefAction - Attaching appender named [stdout] to Logger[ROOT]
12:46:26,253 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationAction - End of configuration.
12:46:26,253 |-INFO in ch.qos.logback.classic.joran.JoranConfigurator@67b6d4ae - Registering current configuration as safe fallback point
12:46:26.258 [main] DEBUG Jena - Jena initialization
12:46:26.335 [main] DEBUG org.apache.jena.util.FileManager - Add location: LocatorFile
12:46:26.335 [main] DEBUG org.apache.jena.util.FileManager - Add location: ClassLoaderLocator
12:46:26.337 [main] DEBUG org.apache.jena.util.LocationMapper - Failed to find configuration: file:location-mapping.rdf;file:location-mapping.n3;file:location-mapping.ttl;file:etc/location-mapping.rdf;file:etc/location-mapping.n3;file:etc/location-mapping.ttl
12:46:26.337 [main] DEBUG org.apache.jena.util.FileManager - Add location: LocatorFile
12:46:26.338 [main] DEBUG org.apache.jena.util.FileManager - Add location: LocatorURL
12:46:26.338 [main] DEBUG org.apache.jena.util.FileManager - Add location: ClassLoaderLocator
12:46:26.343 [main] DEBUG o.a.j.r.s.stream.JenaIOEnvironment - Failed to find configuration: location-mapping.ttl;location-mapping.rdf;location-mapping.n3;etc/location-mapping.rdf;etc/location-mapping.n3;etc/location-mapping.ttl
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/xerces/util/XMLChar
at org.apache.jena.shared.impl.PrefixMappingImpl.checkLegal(PrefixMappingImpl.java:172)
at org.apache.jena.shared.impl.PrefixMappingImpl.setNsPrefix(PrefixMappingImpl.java:72)
at org.apache.jena.shared.PrefixMapping.<clinit>(PrefixMapping.java:219)
at org.apache.jena.sparql.ARQConstants.<clinit>(ARQConstants.java:106)
at org.apache.jena.query.ARQ.init(ARQ.java:588)
at org.apache.jena.sparql.system.InitARQ.start(InitARQ.java:29)
at org.apache.jena.system.JenaSystem.lambda$init$2(JenaSystem.java:119)
at java.util.ArrayList.forEach(Unknown Source)
at org.apache.jena.system.JenaSystem.forEach(JenaSystem.java:194)
at org.apache.jena.system.JenaSystem.forEach(JenaSystem.java:171)
at org.apache.jena.system.JenaSystem.init(JenaSystem.java:117)
at org.apache.jena.rdf.model.ModelFactory.<clinit>(ModelFactory.java:49)
at com.sri.ai.praise.jdsonld.ReadJenaJSONLD.main(ReadJenaJSONLD.java:11)
Caused by: java.lang.ClassNotFoundException: org.apache.xerces.util.XMLChar
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 13 more
最佳答案
仅依赖org.apache.jena:apache-jena-libs:pom:3.6.0的项目的Maven依赖关系应如下所示：[INFO] org.apache.jena:jena-reports-version:jar:0.0.0-SNAPSHOT[INFO] \- org.apache.jena:apache-jena-libs:pom:3.6.0:compile[INFO] +- org.apache.jena:jena-tdb:jar:3.6.0:compile[INFO] | \- org.apache.jena:jena-arq:jar:3.6.0:compile[INFO] | +- org.apache.jena:jena-core:jar:3.6.0:compile[INFO] | | +- org.apache.jena:jena-iri:jar:3.6.0:compile[INFO] | | +- xerces:xercesImpl:jar:2.11.0:compile[INFO] | | | \- xml-apis:xml-apis:jar:1.4.01:compile...
如果找不到xerces，则可能是局部干扰。
关于java - 包含Xerces 2的Jena在要求缺少Xerces的类(class)时失败，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/49716367/