我有一个JSON文件，想要使用Apache Pig加载。
我使用内置的JSONLOADER来加载json数据，下面是示例json数据。
cat jsondata1.json
{ "response": { "id": 10123, "thread": "Sloths", "comments": ["Sloths are adorable So chill"] }, "response_time": 0.425 }
{ "response": { "id": 13828, "thread": "Bigfoot", "comments": ["hello world"] } , "response_time": 0.517 }
这里我使用内置的Json加载器加载json数据。加载时没有错误，但在转储数据时会出现以下错误。
grunt> a = load '/home/cloudera/jsondata1.json' using JsonLoader('response:tuple (id:int, thread:chararray, comments:bag {tuple(comment:chararray)}), response_time:double');
grunt> dump a;
2016-04-17 01:11:13,286 [pool-4-thread-1] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigRecordReader - Current split being processed file:/home/cloudera/jsondata1.json:0+229
2016-04-17 01:11:13,287 [pool-4-thread-1] WARN org.apache.hadoop.conf.Configuration - dfs.https.address is deprecated. Instead, use dfs.namenode.https-address
2016-04-17 01:11:13,311 [pool-4-thread-1] WARN org.apache.pig.data.SchemaTupleBackend - SchemaTupleBackend has already been initialized
2016-04-17 01:11:13,321 [pool-4-thread-1] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapOnly$Map - Aliases being processed per job phase (AliasName[line,offset]): M: a[5,4] C: R:
2016-04-17 01:11:13,349 [Thread-16] INFO org.apache.hadoop.mapred.LocalJobRunner - Map task executor complete.
2016-04-17 01:11:13,351 [Thread-16] WARN org.apache.hadoop.mapred.LocalJobRunner - job_local801054416_0004
java.lang.Exception: org.codehaus.jackson.JsonParseException: Current token (FIELD_NAME) not numeric, can not use numeric value accessors
at [Source: java.io.ByteArrayInputStream@2484de3c; line: 1, column: 120]
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:406)
Caused by: org.codehaus.jackson.JsonParseException: Current token (FIELD_NAME) not numeric, can not use numeric value accessors
at [Source: java.io.ByteArrayInputStream@2484de3c; line: 1, column: 120]
at org.codehaus.jackson.JsonParser._constructError(JsonParser.java:1291)
at org.codehaus.jackson.impl.JsonParserMinimalBase._reportError(JsonParserMinimalBase.java:385)
at org.codehaus.jackson.impl.JsonNumericParserBase._parseNumericValue(JsonNumericParserBase.java:399)
at org.codehaus.jackson.impl.JsonNumericParserBase.getDoubleValue(JsonNumericParserBase.java:311)
at org.apache.pig.builtin.JsonLoader.readField(JsonLoader.java:203)
at org.apache.pig.builtin.JsonLoader.getNext(JsonLoader.java:157)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigRecordReader.nextKeyValue(PigRecordReader.java:211)
at org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.nextKeyValue(MapTask.java:483)
at org.apache.hadoop.mapreduce.task.MapContextImpl.nextKeyValue(MapContextImpl.java:76)
at org.apache.hadoop.mapreduce.lib.map.WrappedMapper$Context.nextKeyValue(WrappedMapper.java:85)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:139)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:672)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:330)
at org.apache.hadoop.mapred.LocalJobRunner$Job$MapTaskRunnable.run(LocalJobRunner.java:268)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
2016-04-17 01:11:13,548 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher - HadoopJobId: job_local801054416_0004
2016-04-17 01:11:13,548 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher - Processing aliases a
2016-04-17 01:11:13,548 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher - detailed locations: M: a[5,4] C: R:
2016-04-17 01:11:18,059 [main] WARN org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher - Ooops! Some job has failed! Specify -stop_on_failure if you want Pig to stop immediately on failure.
2016-04-17 01:11:18,059 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher - job job_local801054416_0004 has failed! Stop running all dependent jobs
2016-04-17 01:11:18,059 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher - 100% complete
2016-04-17 01:11:18,059 [main] ERROR org.apache.pig.tools.pigstats.PigStatsUtil - 1 map reduce job(s) failed!
2016-04-17 01:11:18,060 [main] INFO org.apache.pig.tools.pigstats.SimplePigStats - Detected Local mode. Stats reported below may be incomplete
2016-04-17 01:11:18,060 [main] INFO org.apache.pig.tools.pigstats.SimplePigStats - Script Statistics:
HadoopVersion PigVersion UserId StartedAt FinishedAt Features
2.0.0-cdh4.7.0 0.11.0-cdh4.7.0 cloudera 2016-04-17 01:11:12 2016-04-17 01:11:18 UNKNOWN
Failed!
Failed Jobs:
JobId Alias Feature Message Outputs
job_local801054416_0004 a MAP_ONLY Message: Job failed! file:/tmp/temp-1766116741/tmp1151698221,
Input(s):
Failed to read data from "/home/cloudera/jsondata1.json"
Output(s):
Failed to produce result in "file:/tmp/temp-1766116741/tmp1151698221"
Job DAG:
job_local801054416_0004
2016-04-17 01:11:18,060 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher - Failed!
2016-04-17 01:11:18,061 [main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1066: Unable to open iterator for alias a
Details at logfile: /home/cloudera/pig_1460877001124.log
我无法找到问题。我可以知道如何为上面的json数据定义正确的模式吗？。
答案 0 :(得分：0)
试试这个：
comments:{(chararray)}
因为这个版本：
comments:bag {tuple(comment:chararray)}
符合此JSON架构：
"comments": [{comment:"hello world"}]
你有简单的字符串值，而不是另一个嵌套文档：
"comments": ["hello world"]