- 添加maven依赖
<dependencies>
<dependency>
<groupId>org.apache.hive</groupId>
<artifactId>hive-exec</artifactId>
<version>1.1.0</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>2.6.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<!--这个可以不用,因为我写的是解析json的一个UDF,所以用了阿里的fastjson-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.57</version>
</dependency>
</dependencies>
- 开发代码,继承 UDF,并重载 evaluate
package io.udf.hive;
import com.alibaba.fastjson.JSONObject;
import org.apache.hadoop.hive.ql.exec.UDF;
public class UDFjson extends UDF {
public String evaluate(String input, String key) {
String re = jsonParser(input, key);
return re;
}
public String jsonParser(String in, String key) {
JSONObject object = JSONObject.parseObject(in);
String result = object.getString(key);
return result;
}
}
- 打成 jar 包上传到HDFS
hdfs dfs -put /home/webserver/jars/UDFjson-1.0-SNAPSHOT-jar-with-dependencies.jar /udf/
- 打开hive命令行,选择你需要添加UDF的database:
CREATE FUNCTION json_tuple_test AS 'io.udf.hive.UDFjson' USING JAR 'hdfs:///udf/UDFjson-1.0-SNAPSHOT-jar-with-dependencies.jar’;
- 查看function,在hive命令行执行以下命令:
show functions;
PS:注册的UDF会有database的前缀,所以查看的时候需要注意下