Eclipse中的maven项目引入jar报错的解决方式

一、背景

最近在学习es的使用，先是在一个电脑上写的测试代码，然后代码复制另一台电脑上，没想到maven项目里的pom.xml居然报错了。所以在这里记录一下解决的方式。

（异常是复现的，非第一现场，仅作示例）

二、问题表现

1、从项目上看的表现

 

 2、打开pom的表现

 3、定位到×的地方

null (org.apache.maven.plugins:maven-jar-plugin:2.4:jar:default-jar:package) org.eclipse.core.runtime.operationcanceledexception at 
 org.eclipse.core.runtime.submonitor.checkcanceled(submonitor.java:604) at org.eclipse.core.internal.resources.resource.setderived(resource.java:1611) at 
 org.eclipse.m2e.core.internal.m2eutils.createfolder(m2eutils.java:73) at 
 org.sonatype.m2e.mavenarchiver.internal.abstractmavenarchiverconfigurator.writepom(abstractmavenarchiverconfigurator.java:772) at 
 org.sonatype.m2e.mavenarchiver.internal.abstractmavenarchiverconfigurator$1.build(abstractmavenarchiverconfigurator.java:161) at 
 org.eclipse.m2e.core.internal.builder.mavenbuilderimpl.build(mavenbuilderimpl.java:137) at org.eclipse.m2e.core.internal.builder.mavenbuilder$1.method(mavenbuilder.java:172) at 
 org.eclipse.m2e.core.internal.builder.mavenbuilder$1.method(mavenbuilder.java:1) at org.eclipse.m2e.core.internal.builder.mavenbuilder$buildmethod$1$1.call(mavenbuilder.java:115) at 
 org.eclipse.m2e.core.internal.embedder.mavenexecutioncontext.executebare(mavenexecutioncontext.java:177) at 
 org.eclipse.m2e.core.internal.embedder.mavenexecutioncontext.execute(mavenexecutioncontext.java:112) at 
 org.eclipse.m2e.core.internal.builder.mavenbuilder$buildmethod$1.call(mavenbuilder.java:105) at 
 org.eclipse.m2e.core.internal.embedder.mavenexecutioncontext.executebare(mavenexecutioncontext.java:177) at 
 org.eclipse.m2e.core.internal.embedder.mavenexecutioncontext.execute(mavenexecutioncontext.java:151) at 
 org.eclipse.m2e.core.internal.embedder.mavenexecutioncontext.execute(mavenexecutioncontext.java:99) at 
 org.eclipse.m2e.core.internal.builder.mavenbuilder$buildmethod.execute(mavenbuilder.java:86) at org.eclipse.m2e.core.internal.builder.mavenbuilder.build(mavenbuilder.java:200) at 
 org.eclipse.core.internal.events.buildmanager$2.run(buildmanager.java:735) at org.eclipse.core.runtime.saferunner.run(saferunner.java:42) at 
 org.eclipse.core.internal.events.buildmanager.basicbuild(buildmanager.java:206) at org.eclipse.core.internal.events.buildmanager.basicbuild(buildmanager.java:246) at 
 org.eclipse.core.internal.events.buildmanager$1.run(buildmanager.java:301) at org.eclipse.core.runtime.saferunner.run(saferunner.java:42) at 
 org.eclipse.core.internal.events.buildmanager.basicbuild(buildmanager.java:304) at org.eclipse.core.internal.events.buildmanager.basicbuildloop(buildmanager.java:360) at 
 org.eclipse.core.internal.events.buildmanager.build(buildmanager.java:383) at org.eclipse.core.internal.events.autobuildjob.dobuild(autobuildjob.java:142) at 
 org.eclipse.core.internal.events.autobuildjob.run(autobuildjob.java:232) at org.eclipse.core.internal.jobs.worker.run(worker.java:56)

 

还有一个×（有时有的×能点，有的不能点）

multiple annotations found at this line:
- failure to transfer org.apache.httpcomponents:httpcore:jar:4.4.12 from http://maven.***.com:port/nexus/content/groups/public was cached in the local repository, resolution will not be
reattempted until the update interval of nexus-public-corp-releases has elapsed or updates are forced. original error: could not transfer artifact org.apache.httpcomponents:httpcore:jar:4.4.12 from/to
nexus-public-corp-releases (http://maven.***.com:port/nexus/content/groups/public): the operation was cancelled. org.eclipse.aether.transfer.artifacttransferexception: failure to transfer
org.apache.httpcomponents:httpcore:jar:4.4.12 from http://maven.***.com:port/nexus/content/groups/public was cached in the local repository, resolution will not be reattempted until the update
interval of nexus-public-corp-releases has elapsed or updates are forced. original error: could not transfer artifact org.apache.httpcomponents:httpcore:jar:4.4.12 from/to nexus-public-corp-releases
(http://maven.***.com:port/nexus/content/groups/public): the operation was cancelled. at
org.eclipse.aether.internal.impl.defaultupdatecheckmanager.newexception(defaultupdatecheckmanager.java:238) at
org.eclipse.aether.internal.impl.defaultupdatecheckmanager.checkartifact(defaultupdatecheckmanager.java:206) at
org.eclipse.aether.internal.impl.defaultartifactresolver.gatherdownloads(defaultartifactresolver.java:585) at
org.eclipse.aether.internal.impl.defaultartifactresolver.performdownloads(defaultartifactresolver.java:503) at org.eclipse.aether.internal.impl.defaultartifactresolver.resolve(defaultartifactresolver.java:421)
at org.eclipse.aether.internal.impl.defaultartifactresolver.resolveartifacts(defaultartifactresolver.java:246) at
org.eclipse.aether.internal.impl.defaultrepositorysystem.resolvedependencies(defaultrepositorysystem.java:367) at
org.apache.maven.project.defaultprojectdependenciesresolver.resolve(defaultprojectdependenciesresolver.java:205) at
org.apache.maven.project.defaultprojectbuilder.resolvedependencies(defaultprojectbuilder.java:215) at org.apache.maven.project.defaultprojectbuilder.build(defaultprojectbuilder.java:188) at
org.apache.maven.project.defaultprojectbuilder.build(defaultprojectbuilder.java:119) at org.eclipse.m2e.core.internal.embedder.mavenimpl.readmavenproject(mavenimpl.java:636) at
org.eclipse.m2e.core.internal.project.registry.defaultmavendependencyresolver.resolveprojectdependencies(defaultmavendependencyresolver.java:63) at
org.eclipse.m2e.core.internal.project.registry.projectregistrymanager.refreshphase2(projectregistrymanager.java:530) at
org.eclipse.m2e.core.internal.project.registry.projectregistrymanager$3.call(projectregistrymanager.java:492) at
org.eclipse.m2e.core.internal.project.registry.projectregistrymanager$3.call(projectregistrymanager.java:1) at
org.eclipse.m2e.core.internal.embedder.mavenexecutioncontext.executebare(mavenexecutioncontext.java:177) at
org.eclipse.m2e.core.internal.embedder.mavenexecutioncontext.execute(mavenexecutioncontext.java:151) at

 

 三、定位、解决问题

1、定位问题

从上述的那个×的描述，可以看到原因。

org.eclipse.core.runtime.operationcanceledexception

 操作被取消异常。

也就是在引入依赖的时候，maven还在下载jar包时被终止了。

我的项目出现上述异常，就是因为下的过程中网络卡了，然后我就手动结束了下载过程。

这种问题之前遇到过，当时总怀疑是项目结构有问题，或者jar有问题，没有想到是这个原因。

这次又遇到这个问题的时候，我回想，在自己电脑上都正常，在公司电脑就有问题？不应该。

问题定位了，接下来就是解决问题了。

2、解决问题

打开项目的build path，可以看到libraries中的maven依赖那块有×。

 

 

 展开之后，就可以看到是哪个jar包异常。

 

根据路径找到本地的maven仓库对应的路径。可以点进去看一下，有几个文件，但是没有jar文件。

解决方法：删除4.4.12这个文件夹。然后随意改动一下pom.xml后保存，让eclipse重新下一下，问题就解决了。