Solve the problem that sqoop cannot find the jar under $SQOOP_HOME/lib

    Add <property>
        <name>mapreduce.framework.name</name>
        <value>yarn</value>
        <description>Execution framework set to Hadoop YARN.</description>
    </property under hadoop's hdfs-site.xml >
That's it.


After sqoop imports data, there will be corresponding files under hdfs. If you continue to execute the same command, there will be problems.
You can use the following commands to operate
   1. hadoop fs -ls -R (view the hdfs file)
   2. hadoop fs -rmr file name (delete the file with the corresponding file name)