解决hive查询parquet表报错NullPointerException异常问题(ProjectionPusher.java:118)

这个问题在hive3.1已经解决，但是我查看源码之后发现hive2.3.6还是没解决，其实解决办法很简单，不知道为什么一直不更新，对应hivebug是HIVE-16958，我的报错信息如下

Diagnostic Messages for this Task:
Error: java.io.IOException: java.lang.reflect.InvocationTargetException
	at org.apache.hadoop.hive.io.HiveIOExceptionHandlerChain.handleRecordReaderCreationException(HiveIOExceptionHandlerChain.java:97)
	at org.apache.hadoop.hive.io.HiveIOExceptionHandlerUtil.handleRecordReaderCreationException(HiveIOExceptionHandlerUtil.java:57)
	at org.apache.hadoop.hive.shims.HadoopShimsSecure$CombineFileRecordReader.initNextRecordReader(HadoopShimsSecure.java:271)
	at org.apache.hadoop.hive.shims.HadoopShimsSecure$CombineFileRecordReader.(HadoopShimsSecure.java:217)
	at org.apache.hadoop.hive.shims.HadoopShimsSecure$CombineFileInputFormatShim.getRecordReader(HadoopShimsSecure.java:345)
	at org.apache.hadoop.hive.ql.io.CombineHiveInputFormat.getRecordReader(CombineHiveInputFormat.java:695)
	at org.apache.hadoop.mapred.MapTask$TrackedRecordReader.(MapTask.java:169)
	at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:438)
	at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
	at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:177)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:422)
	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1886)
	at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:171)
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at org.apache.hadoop.hive.shims.HadoopShimsSecure$CombineFileRecordReader.initNextRecordReader(HadoopShimsSecure.java:257)
	... 11 more
Caused by: java.lang.NullPointerException
	at java.util.AbstractCollection.addAll(AbstractCollection.java:343)
	at org.apache.hadoop.hive.ql.io.parquet.ProjectionPusher.pushProjectionsAndFilters(ProjectionPusher.java:118)
	at org.apache.hadoop.hive.ql.io.parquet.ProjectionPusher.pushProjectionsAndFilters(ProjectionPusher.java:189)
	at org.apache.hadoop.hive.ql.io.parquet.ParquetRecordReaderBase.getSplit(ParquetRecordReaderBase.java:75)
	at org.apache.hadoop.hive.ql.io.parquet.read.ParquetRecordReaderWrapper.(ParquetRecordReaderWrapper.java:75)
	at org.apache.hadoop.hive.ql.io.parquet.read.ParquetRecordReaderWrapper.(ParquetRecordReaderWrapper.java:60)
	at org.apache.hadoop.hive.ql.io.parquet.MapredParquetInputFormat.getRecordReader(MapredParquetInputFormat.java:75)
	at org.apache.hadoop.hive.ql.io.CombineHiveRecordReader.(CombineHiveRecordReader.java:99)
	... 16 more


FAILED: Execution Error, return code 2 from org.apache.hadoop.hive.ql.exec.mr.MapRedTask
MapReduce Jobs Launched: 
Stage-Stage-1: Map: 4   Cumulative CPU: 43.26 sec   HDFS Read: 900444378 HDFS Write: 1356093 SUCCESS
Stage-Stage-2: Map: 1   HDFS Read: 0 HDFS Write: 0 FAIL
Total MapReduce CPU Time Spent: 43 seconds 260 msec

其实解决这个问题的办法就是修改ProjectionPusher这个类的一行代码，我没有找到不修改源码解决的办法，如果有人找到了请告知一下谢谢。我修改的方案是按照hive3.1进行的修改，所以应该不会产生新BUG。

根据报错ProjectionPusher.java:118行，所以修改ProjectionPusher.java:118

原代码为

neededColumnIDs.addAll(ts.getNeededColumnIDs());
neededNestedColumnPaths.addAll(ts.getNeededNestedColumnPaths());

修改为

neededColumnIDs.addAll(ts.getNeededColumnIDs());
if (ts.getNeededNestedColumnPaths() != null) {
    neededNestedColumnPaths.addAll(ts.getNeededNestedColumnPaths());
}

代码路径在

D:\apache-hive-2.3.6-src\ql\src\java\org\apache\hadoop\hive\ql\io\parquet

然后重新打包

mvn clean package -DskipTests