[hadoop那些事] 错误: 找不到或无法加载主类 org.apache.hadoop.mapreduce.v2.app.MRAppMaster

hadoop classpath

Linux返回类似这样的代码

/usr/hadoop/hadoop-3.1.2/etc/hadoop:/usr/hadoop/hadoop-3.1.2/share/hadoop/common/lib/:/usr/hadoop/hadoop-3.1.2/share/hadoop/common/:/usr/hadoop/hadoop-3.1.2/share/hadoop/hdfs:/usr/hadoop/hadoop-3.1.2/share/hadoop/hdfs/lib/:/usr/hadoop/hadoop-3.1.2/share/hadoop/hdfs/:/usr/hadoop/hadoop-3.1.2/share/hadoop/mapreduce/lib/:/usr/hadoop/hadoop-3.1.2/share/hadoop/mapreduce/:/usr/hadoop/hadoop-3.1.2/share/hadoop/yarn:/usr/hadoop/hadoop-3.1.2/share/hadoop/yarn/lib/:/usr/hadoop/hadoop-3.1.2/share/hadoop/yarn/

在hadoop的 yarn-site.xml里面添加 value里面复制你电脑返回的代码

	<property>
        <name>yarn.application.classpath</name>
        <value>/usr/hadoop/hadoop-3.1.2/etc/hadoop:/usr/hadoop/hadoop-3.1.2/share/hadoop/common/lib/*:/usr/hadoop/hadoop-3.1.2/share/hadoop/common/*:/usr/hadoop/hadoop-3.1.2/share/hadoop/hdfs:/usr/hadoop/hadoop-3.1.2/share/hadoop/hdfs/lib/*:/usr/hadoop/hadoop-3.1.2/share/hadoop/hdfs/*:/usr/hadoop/hadoop-3.1.2/share/hadoop/mapreduce/lib/*:/usr/hadoop/hadoop-3.1.2/share/hadoop/mapreduce/*:/usr/hadoop/hadoop-3.1.2/share/hadoop/yarn:/usr/hadoop/hadoop-3.1.2/share/hadoop/yarn/lib/*:/usr/hadoop/hadoop-3.1.2/share/hadoop/yarn/*</value>
    </property>

重新启动hadoop即可