我们在运行MapReduce的时候,会报一个空指针的异常,后面的报错原因是下面一堆东西,其实很简单,是我们Driver端的Text的包导错了
WARN org.apache.hadoop.mapred.MapTask.createSortingCollector() - Unable to initialize MapOutputCollector org.apache.hadoop.mapred.MapTask$MapOutputBuffer
java.lang.NullPointerException
at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.init(MapTask.java:1011)
at org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:402)
at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:81)
at org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:698)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:770)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:341)
at org.apache.hadoop.mapred.LocalJobRunner$Job$MapTaskRunnable.run(LocalJobRunner.java:243)
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)
这个是错误的包
import com.sun.jersey.core.impl.provider.entity.XMLJAXBElementProvider.Text;
这个是正确的包
import org.apache.hadoop.io.Text;
一般情况下,改了之后就好了