2020-03-18 06:22:38,641 warn[main]org.apache.hadoop.mapred.yarnchild:异常运行子级：java.lang.illegalstateexception:未知可写代码：20位于org.apache.crunch.types.writable.tuplewritable.getwritable（tuplewritable）。java:225)在org.apache.crunch.types.writable.tuplewritable.readfields（tuplewritable。java:205)在org.apache.crunch.types.writable.writables.create（可写）。java:383)org.apache.crunch.types.writable.writables.access$300（可写）。java:75)在org.apache.crunch.types.writable.writables$twtuplemapfn.map（writables。java:458)在org.apache.crunch.types.writable.writables$twtuplemapfn.map（writables。java:395)在org.apache.crunch.fn.pairmapfn.map（pairmapfn。java:67)在org.apache.crunch.fn.pairmapfn.map（pairmapfn。java:26)在org.apache.crunch.mapfn.process（mapfn。java:34)在org.apache.crunch.impl.mr.run.rtnode.process（rtnode。java:98)在org.apache.crunch.impl.mr.run.rtnode.process（rtnode。java:109)在org.apache.crunch.impl.mr.run.crunchmapper.map（crunchmapper。java:60)在org.apache.hadoop.mapreduce.mapper.run（mapper。java:145)在org.apache.hadoop.mapred.maptask.runnewmapper（maptask。java:793)在org.apache.hadoop.mapred.maptask.run（maptask。java:341)在org.apache.hadoop.mapred.yarnchild$2.run（yarnchild。java:164)在javax.security.auth.subject.doas（主题）中的java.security.accesscontroller.doprivileged（本机方法）。java:422)在org.apache.hadoop.security.usergroupinformation.doas（usergroupinformation。java:1917)在org.apache.hadoop.mapred.yarnchild.main（yarnchild。java:158)