关于hive自定义JsonSerde处理json

偏执的太偏执、 2022-06-13 06:50 464阅读 0赞

[Hive][]自身提供UDF函数对json数据格式解析的函数，即get\_json\_object（…）与json\_tuple(…)支持json数据的操作，但是使用效果并不是非常理想。如果可以像普通[hive][Hive]建表指定字段映射到json中的key就太好了！幸好hive本身提供了数据序列化反序列化的接口Serde，开发者只需要自定义实现Serde接口实现自己的逻辑即可。下面介绍的是通过开源工具Hive-JSON-Serde-develop来实现的序列化反序列化操作实例。

步骤：

1、下载  hive-json-serde-0.2.jar

2、将jar包放入lib下或者自己新建自己的jar包存储文件夹

3、在hive文件夹的conf文件夹中将 hive-env.sh.template改为hive-env.sh去掉最后一行注释加入你的jar包所在路径

4、编写hive建表语句

create table json_tab (
        `_area` string,
        `_name` string,
        `_sex`  string,
        `_uuid` string,
    )
    -- 指定Serde类
    row format serde 'org.openx.data.jsonserde.JsonSerDe'

stored as textfile

-- 指定json数据位置
    location '/data/test/json/';

注意如果没有导包会出这样的错

Total jobs = 1 Launching Job 1 out of 1 Number of reduce tasks is set to 0 since there's no reduce operator Starting Job = job_1498788221191_0007, Tracking URL = http://zj-db0236deMacBook-Pro.local:8088/proxy/application_1498788221191_0007/ Kill Command = /Users/zj-db0236/Downloads/hadoop-2.7.2/bin/hadoop job -kill job_1498788221191_0007 Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0 2017-06-30 11:14:17,128 Stage-1 map = 0%, reduce = 0% 2017-06-30 11:15:17,675 Stage-1 map = 0%, reduce = 0% 2017-06-30 11:16:18,346 Stage-1 map = 0%, reduce = 0% 2017-06-30 11:16:37,869 Stage-1 map = 100%, reduce = 0% Ended Job = job_1498788221191_0007 with errors Error during job, obtaining debugging information... Examining task ID: task_1498788221191_0007_m_000000 (and more) from job job_1498788221191_0007 Task with the most failures(4): ----- Task ID: task_1498788221191_0007_m_000000 URL: http://0.0.0.0:8088/taskdetails.jsp?jobid=job_1498788221191_0007&tipid=task_1498788221191_0007_m_000000 ----- Diagnostic Messages for this Task: Error: java.lang.RuntimeException: Error in configuring object at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112) at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78) at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136) at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:449) at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343) at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:164) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:415) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657) at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158) Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109) ... 9 more Caused by: java.lang.RuntimeException: Error in configuring object at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:112) at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:78) at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:136) at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:38) ... 14 more Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109) ... 17 more Caused by: java.lang.RuntimeException: Map operator initialization failed at org.apache.hadoop.hive.ql.exec.mr.ExecMapper.configure(ExecMapper.java:154) ... 22 more Caused by: org.apache.hadoop.hive.ql.metadata.HiveException: java.lang.ClassNotFoundException: Class org.apache.hadoop.hive.contrib.serde2.JsonSerde not found at org.apache.hadoop.hive.ql.exec.MapOperator.getConvertedOI(MapOperator.java:335) at org.apache.hadoop.hive.ql.exec.MapOperator.setChildren(MapOperator.java:353) at org.apache.hadoop.hive.ql.exec.mr.ExecMapper.configure(ExecMapper.java:123) ... 22 more Caused by: java.lang.ClassNotFoundException: Class org.apache.hadoop.hive.contrib.serde2.JsonSerde not found at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:2101) at org.apache.hadoop.hive.ql.exec.MapOperator.getConvertedOI(MapOperator.java:305) ... 24 more FAILED: Execution Error, return code 2 from org.apache.hadoop.hive.ql.exec.mr.MapRedTask MapReduce Jobs Launched: Job 0: Map: 1 HDFS Read: 0 HDFS Write: 0 FAIL Total MapReduce CPU Time Spent: 0 msec

[Hive]: http://lib.csdn.net/base/hive