maven pom文件报错

Execution default-testResources of goal org.apache.maven.plugins:maven-resources-plugin:2.5:testResources failed: A required class was missing while executing org.apache.maven.plugins:maven-resources-plugin:2.5:testResources: org/codehaus/plexus/util/StringUtils
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realm = plugin>org.apache.maven.plugins:maven-resources-plugin:2.5
strategy = org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy
urls[0] = file:/E:/maven-repository/repository/org/apache/maven/plugins/maven-resources-plugin/2.5/maven-resources-plugin-2.5.jar
urls[1] = file:/E:/maven-repository/repository/org/apache/maven/reporting/maven-reporting-api/2.0.6/maven-reporting-api-2.0.6.jar
urls[2] = file:/E:/maven-repository/repository/org/apache/maven/doxia/doxia-sink-api/1.0-alpha-7/doxia-sink-api-1.0-alpha-7.jar
urls[3] = file:/E:/maven-repository/repository/commons-cli/commons-cli/1.0/commons-cli-1.0.jar
urls[4] = file:/E:/maven-repository/repository/org/codehaus/plexus/plexus-interactivity-api/1.0-alpha-4/plexus-interactivity-api-1.0-alpha-4.jar
urls[5] = file:/E:/maven-repository/repository/junit/junit/3.8.1/junit-3.8.1.jar
urls[6] = file:/E:/maven-repository/repository/org/codehaus/plexus/plexus-utils/2.0.5/plexus-utils-2.0.5.jar
urls[7] = file:/E:/maven-repository/repository/org/apache/maven/shared/maven-filtering/1.0/maven-filtering-1.0.jar
urls[8] = file:/E:/maven-repository/repository/org/codehaus/plexus/plexus-interpolation/1.13/plexus-interpolation-1.13.jar
Number of foreign imports: 4
import: Entry[import org.sonatype.plexus.build.incremental from realm ClassRealm[plexus.core, parent: null]]
import: Entry[import org.codehaus.plexus.util.Scanner from realm ClassRealm[plexus.core, parent: null]]
import: Entry[import org.codehaus.plexus.util.AbstractScanner from realm ClassRealm[plexus.core, parent: null]]
import: Entry[import from realm ClassRealm[maven.api, parent: null]]

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(org.apache.maven.plugins:maven-resources-plugin:2.5:testResources:default-testResources:process-test-resources)