引入依赖

<dependency>
	 <groupId>org.apache.hive</groupId>
	 <artifactId>hive-exec</artifactId>
	 <version>3.1.2</version>
</dependency>

编写函数

注意必须要继承GenericUDF 类

import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;

public class SimilarEval extends GenericUDF {
    /**
     * 初始化方法，一般用来校验数据参数个数，返回值是int类型的PrimitiveObjectInspectorFactory
     * @param objectInspectors
     * @return
     * @throws UDFArgumentException
     */

    @Override
    public ObjectInspector initialize(ObjectInspector[] objectInspectors) throws UDFArgumentException {
        if (objectInspectors.length != 2){
            //判断参数个数是否为2，抛出异常
            throw new UDFArgumentException("参数个数必须为2，请重新输入");
        }
        return PrimitiveObjectInspectorFactory.javaIntObjectInspector;
    }

    /**
     * 业务逻辑处理方法
     * @param
     * @return
     * @throws HiveException
     */

    @Override
    public Object evaluate(DeferredObject[] deferredObjects) throws HiveException {
        //获取输入的参数
        String targetStr = deferredObjects[0].get().toString();
        String sourceStr = deferredObjects[1].get().toString();
        //判断输入数据是否为null，如果为null，返回0
        if (targetStr == null || sourceStr == null){
            return 0;
        }else{
            //输入数据不为null，进行业务处理
            int tar_len = targetStr.length();
            int b = 0;
            for (int i = 0; i < tar_len; i++) {
                String tmpChar = targetStr.substring(i,i+1);
                int a = sourceStr.indexOf(tmpChar);
                if (a >= 0){
                    a+=1;
                    b = b +1;
                } else{
                    a = 0;
                }
            }
            int result = (int) Math.round((b*100)/(double)tar_len);
            return result;
        }
    }

    /**
     *
     * @param strings
     * @return
     */
    @Override
    public String getDisplayString(String[] strings) {
        return "";
    }
}

项目结构

打成jar包，并上传到linux服务器，将jar包添加到hive指定路径

# 将jar包添加到hive指定路径
add jar hdfs:/stq/ltdq/jars/SimilarEval-1.0-SNAPSHOT.jar;
# 创建函数
create function similar_eval as 'SimilarEval';

使用效果