错误信息：

java.lang.Exception: java.lang.ArrayIndexOutOfBoundsException: 1
    at org.apache.hadoop.mapred.LocalJobRunner$Job.runTasks(LocalJobRunner.java:492)
    at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:552)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 1
    at exper.Filter$Map.map(Filter.java:25)
    at exper.Filter$Map.map(Filter.java:19)
    at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:146)
    at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:799)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:347)
    at org.apache.hadoop.mapred.LocalJobRunner$Job$MapTaskRunnable.run(LocalJobRunner.java:271)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
错误原因：源代码中设置数据的分隔符为空格，而数据集中代码分隔符为tab制表符
修改标红语句：

public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
    String line = value.toString();
    System.out.println(line);
    String arr[] = line.split("\t");
    newKey.set(arr[1]);
    context.write(newKey, NullWritable.get());
    System.out.println(newKey);
}

之后在Linux上运行jar文件：
在存储jar包的文件夹下输入命令：
hadoop jar MapreduceDemo-1.0-SNAPSHOT.jar exper.Filter /mymapreduce2/in/buyer_myfavorite1 /user/root/mymapreduce2/out
运行成功！