我正在尝试运行mongodb和hadoop地图减少我得到下面的警告和错误，请帮助我提前修复这些感谢
13/06/20 10:42:55 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
13/06/20 10:42:55 WARN mapred.JobClient: Use GenericOptionsParser for parsing the arguments. Applications should implement Tool for the same.
13/06/20 10:42:55 WARN mapred.JobClient: No job jar file set. User classes may not be found. See JobConf(Class) or JobConf#setJar(String).
13/06/20 10:42:55 INFO util.MongoSplitter: Calculate Splits Code ... Use Shards? false, Use Chunks? true; Collection Sharded? false
13/06/20 10:42:55 INFO util.MongoSplitter: Creation of Input Splits is enabled.
13/06/20 10:42:55 INFO util.MongoSplitter: Using Unsharded Split mode (Calculating multiple splits though)
13/06/20 10:42:55 INFO util.MongoSplitter: Calculating unsharded input splits on namespace 'test.in' with Split Key '{ "_id" : 1}' and a split size of '8'mb per
13/06/20 10:42:55 INFO mapred.JobClient: Cleaning up the staging area file:/tmp/hadoop-patil/mapred/staging/patil916888189/.staging/job_local_0001
Exception in thread "main" java.lang.IllegalArgumentException: Unable to calculate input splits: ns not found
at com.mongodb.hadoop.util.MongoSplitter.calculateUnshardedSplits(MongoSplitter.java:106)
at com.mongodb.hadoop.util.MongoSplitter.calculateSplits(MongoSplitter.java:75)
at com.mongodb.hadoop.MongoInputFormat.getSplits(MongoInputFormat.java:51)
at org.apache.hadoop.mapred.JobClient.writeNewSplits(JobClient.java:962)
at org.apache.hadoop.mapred.JobClient.writeSplits(JobClient.java:979)
at org.apache.hadoop.mapred.JobClient.access$600(JobClient.java:174)
at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:897)
at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:850)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:850)
at org.apache.hadoop.mapreduce.Job.submit(Job.java:500)
at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:530)
at MapReduce.WordCount.main(WordCount.java:83)
"ns not found"错误表示mongo-hadoop连接器找不到您的输入集合。您检查过输入URI是否有效并且集合是否存在吗?