Hive自定义函数UDF(二)

╰+攻爆jí腚メ 2022-09-09 09:57 280阅读 0赞

# 1、需求 #

自定义将字符串转大写和小写的Hive UDF；

# 2、maven依赖及代码 #

<dependencies>
            <dependency>
                <groupId>org.apache.hive</groupId>
                <artifactId>hive-exec</artifactId>
                <version>1.2.1</version>
            </dependency>
            <dependency>
                <groupId>org.apache.hadoop</groupId>
                <artifactId>hadoop-common</artifactId>
                <version>2.7.4</version>
            </dependency>
        </dependencies>

package com.hive;
    
    import org.apache.hadoop.hive.ql.exec.UDF;
    
    public class StrToUpperFunc extends UDF {
        public String evaluate(String str){
            //字符转化为大写
            return str.toUpperCase();
        }
    }

package com.hive;
    
    import org.apache.hadoop.hive.ql.exec.UDF;
    
    public class StrToLowerFunc extends UDF {
        //字符转化为小写
        public String evaluate(String str){
            return str.toLowerCase();
        }
    }

# 3、操作步骤 #

**(1)将代码打包生成的hiveUdf.jar上传到hdfs的/udfFunc下；**

**(2)在hive端创建函数：**

hive> create Function strToL  as "com.hive.StrToLowerFunc" USING JAR 'hdfs:///udfFunc/hiveUdf.jar';
    
    hive> create Function strToU  as "com.hive.StrToUpperFunc" USING JAR 'hdfs:///udfFunc/hiveUdf.jar';

**（3）应用测试：**

hive> select * from student;
    OK
    1       zhangSan
    2       liSi
    3       wangWu
    Time taken: 0.038 seconds, Fetched: 3 row(s)
    hive> select strToU(name) from student;
    OK
    ZHANGSAN
    LISI
    WANGWU
    Time taken: 0.073 seconds, Fetched: 3 row(s)
    hive> select strToL(name) from student;
    OK
    zhangsan
    lisi
    wangwu
    Time taken: 0.041 seconds, Fetched: 3 row(s)