当我运行带有MultipleOutputs的基本MRUnit时,出现以下异常:
java.lang.NullPointerException
at org.apache.hadoop.fs.Path.<init>(Path.java:105)
at org.apache.hadoop.fs.Path.<init>(Path.java:94)
at org.apache.hadoop.mapreduce.lib.output.FileOutputFormat.getDefaultWorkFile(FileOutputFormat.java:264)
at org.apache.hadoop.mapreduce.lib.output.TextOutputFormat.getRecordWriter(TextOutputFormat.java:125)
at org.apache.hadoop.mapreduce.lib.output.MultipleOutputs.getRecordWriter(MultipleOutputs.java:405)
at org.apache.hadoop.mapreduce.lib.output.MultipleOutputs.write(MultipleOutputs.java:387)
at com.skobbler.scratch.MOutputReduce.reduce(MOutputReduce.java:45)
at com.skobbler.scratch.MOutputReduce.reduce(MOutputReduce.java:28)
at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:164)
at org.apache.hadoop.mrunit.mapreduce.ReduceDriver.run(ReduceDriver.java:265)
at org.apache.hadoop.mrunit.mapreduce.ReducePhaseRunner.runReduce(ReducePhaseRunner.java:85)
at org.apache.hadoop.mrunit.mapreduce.MapReduceDriver.run(MapReduceDriver.java:249)
at org.apache.hadoop.mrunit.TestDriver.runTest(TestDriver.java:640)
at org.apache.hadoop.mrunit.TestDriver.runTest(TestDriver.java:627)
我发现请求了 mapred.output.dir 配置,为空。简单输出不会出现此问题。
MRUnit代码:
@Test
public void testMultiOutput() throws IOException{
MapReduceDriver<LongWritable, Text, Text, Text, Text, Text> mapReduceDriver = createMapReduceDrive();
mapReduceDriver.withInput(new LongWritable(0L), new Text("a,b"));
mapReduceDriver.withInput(new LongWritable(0L), new Text("a,c"));
mapReduceDriver.withMultiOutput("foo", new Text("a"), new Text("2"));
mapReduceDriver.runTest();
}
private MapReduceDriver<LongWritable, Text, Text, Text, Text, Text> createMapReduceDrive() {
MOutputMap mapper = new MOutputMap();
MOutputReduce reducer = new MOutputReduce();
return MapReduceDriver.newMapReduceDriver(mapper, reducer);
}
如何在不指定hadoop系统/输出路径的情况下运行测试。
Hadoop 2,MRUnit 1.1.0
最佳答案
是的,我遇到了这个问题。但是我从其源代码中找到了解决方案。
TestDriver.java
您可以使用getConfiguration()方法获取JobConfiguration对象,然后设置outputdir。
Configuration conf = mapReduceDriver.getConfiguration();
conf.set("mapreduce.output.fileoutputformat.outputdir", "aa");