1. 创建maven项目
   file>new>project

   
   
   

   2.添加依赖的jar包，第一次添加可能有点慢

   

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>scc</groupId>
    <artifactId>UDF</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-client</artifactId>
            <version>2.7.3</version>
        </dependency>
        <dependency>
            <groupId>org.apache.hive</groupId>
            <artifactId>hive-exec</artifactId>
            <version>1.2.1</version>
        </dependency>

    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>1.4</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <filters>
                                <filter>
                                    <artifact>*:*</artifact>
                                    <excludes>
                                        <exclude>META-INF/*.SF</exclude>
                                        <exclude>META-INF/*.DSA</exclude>
                                        <exclude>META-INF/*.RSA</exclude>
                                    </excludes>
                                </filter>
                            </filters>

                            <transformers>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                    <resource>META-INF/spring.handlers</resource>
                                </transformer>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>com.neu.hive.UDF.ToUpperCaseUDF</mainClass>
                                </transformer>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                    <resource>META-INF/spring.schemas</resource>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

导入完毕后左边多出很多jar包，右边则没有红色横杠

3.开始开发
在java下新建new>package

上传服务器，加载jar包，创建临时函数

add jar /usr/local/usrJars/dulm/hiveUDF-0.0.1-SNAPSHOT-all.jar; 
create temporary function my_uppercase as 'com.neu.hive.UDF.ToUpperCaseUDF';
创建临时的方法叫做my_uppercase   as  你的包名+类名。
select my_uppercase(datasource) from tenmindata limit 10;
测试使用： 选出字段datasource下的数据并全部转为大写，显示前10条。

码表是txt格式，关联表不管什么格式，输入输出都是string类型
add jar /root/yl/udf_province4.jar;
create temporary function split_province_txt as 'hive_udf_province.UDF_province_name_txt';
select split_province_txt(province_id) from yl.dim_province;
select split_province_txt(province_id) from yl.dim_province_orc;

线上服务要在每个库上面创建一下永久函数。

创建永久函数
CREATE FUNCTION dws.bss_city_code AS 'com.ysten.bigdata.hive.udf.GetCityBYBssCity';