Hadoop_hdfsjava.lang.IllegalArgumentException: java.net.UnknownHostException: master

我不是女神ヾ 2023-09-26 11:48 56阅读 0赞

## 问题 ##

使用JAVA\_API对于Hadoop\_hdfs模块进行操作，进行连接操作时报错

### 详细问题 ###

![在这里插入图片描述][57667dc06d7a4a8c8cbf3b3a41137d9b.png]

log4j:WARN No appenders could be found for logger (org.apache.hadoop.util.Shell).
    log4j:WARN Please initialize the log4j system properly.
    log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
    
    java.lang.IllegalArgumentException: java.net.UnknownHostException: master
    
    	at org.apache.hadoop.security.SecurityUtil.buildTokenService(SecurityUtil.java:377)
    	at org.apache.hadoop.hdfs.NameNodeProxies.createNonHAProxy(NameNodeProxies.java:320)
    	at org.apache.hadoop.hdfs.NameNodeProxies.createProxy(NameNodeProxies.java:176)
    	at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:687)
    	at org.apache.hadoop.hdfs.DFSClient.<init>(DFSClient.java:628)
    	at org.apache.hadoop.hdfs.DistributedFileSystem.initialize(DistributedFileSystem.java:149)
    	at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:2667)
    	at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:93)
    	at org.apache.hadoop.fs.FileSystem$Cache.getInternal(FileSystem.java:2701)
    	at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:2683)
    	at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:372)
    	at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:171)
    	at com.hdfs.demo.HDFSDemo.conn(HDFSDemo.java:20)
    	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    	at java.lang.reflect.Method.invoke(Method.java:498)
    	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
    	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
    	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
    	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:220)
    	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:53)
    Caused by: java.net.UnknownHostException: master
    	... 36 more
    
    
    java.lang.NullPointerException
    	at com.hdfs.demo.HDFSDemo.close(HDFSDemo.java:34)
    	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    	at java.lang.reflect.Method.invoke(Method.java:498)
    	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:33)
    	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
    	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
    	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:220)
    	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:53)
    
    
    Process finished with exit code -1

### 解决方案 ###

对于 r e s o u r c e s resources resources包下的 h d f s − s i t e . x m l hdfs- site.xml hdfs−site.xml

![在这里插入图片描述][8df4fe4c3e2447d2ba376d0215ea1ed0.png]  
增加如下配置

<property>
        <name>dfs.permissions.enabled</name>
        <value>false</value>
    </property>

同时， 对于虚拟机

/usr/local/hadoop/etc/hadoop/

增加如下配置

<property>
        <name>dfs.permissions.enabled</name>
        <value>false</value>
    </property>

即  
![在这里插入图片描述][f37f9c07711d4ef9a9ecf88a0ac8fa5e.png]  
![在这里插入图片描述][955109fa84ac4356ba43927f4109cbf4.png]

### 原因 ###

配置项dfs.permissions.enabled控制权限的开关，true表示开启，false表示关闭。默认配置为开启  
没有开启权限控制时，任何用户都可以对任意文件进行读写删除等操作。

[57667dc06d7a4a8c8cbf3b3a41137d9b.png]: https://img-blog.csdnimg.cn/57667dc06d7a4a8c8cbf3b3a41137d9b.png
[8df4fe4c3e2447d2ba376d0215ea1ed0.png]: https://img-blog.csdnimg.cn/8df4fe4c3e2447d2ba376d0215ea1ed0.png
[f37f9c07711d4ef9a9ecf88a0ac8fa5e.png]: https://img-blog.csdnimg.cn/f37f9c07711d4ef9a9ecf88a0ac8fa5e.png
[955109fa84ac4356ba43927f4109cbf4.png]: https://img-blog.csdnimg.cn/955109fa84ac4356ba43927f4109cbf4.png