hive udtf 函数：输入一个字符串，将这个字符串按照特殊的逻辑处理之后，输出4个字段

这里要继承GenericUDTF 这个抽象类，直接上代码：

package com.xxx.hive.udf;
import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.exec.UDFArgumentLengthException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDTF;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;

import java.util.ArrayList;

/**
 * @author xxx
 * CREATE temporary function  details as 'com.xxx.hive.udf.Details' USING JAR '';
 */
@Description(name = "details", value = "_FUNC_(expr) - ")

public class Details extends GenericUDTF {

    @Override
    public void close() throws HiveException {

    }


    @Override
    public void process(Object[] objects) throws HiveException {
        if (objects.length == 0 || objects == null) {
            return;
        }
        String input = objects[0].toString();
        if (StringUtils.isEmpty(input)) {
            return;
        }
        //example data
        String details = "0_0_0_0_0~0_0~0_0_0_0_25-1800~0~19~0~19_4800~0~80~0~80_21200~1~0~0~0_20600~1~0~0~0_21100~1~0~0~0;" +
                "1_1_1_0_9~8_9~9_0_0_27750_24-1800~0~19~0~19_4800~0~80~0~80_21200~1~0~0~0_20600~1~0~0~0_21100~1~0~0~0";

        String[] lines = input.split(";");
        for (String line : lines) {
            String[] arrs = line.split("-");
            if (arrs.length < 2) {
                System.out.println("+++++" + input);
                continue;
            }
            String[] header = arrs[0].split("_");
            String[] steps = arrs[1].split("_");
            /*
            BEGIN: 2024-04-02 0~0无法转数字兼容
             */
            try {
                Integer.valueOf(header[3]);
            } catch (Exception e) {
                continue;
            }
            /*
            END: 2024-04-02 0~0无法转数字兼容
             */
            if (header.length > 4 && Integer.valueOf(header[3]) == 2) {
                continue;
            }
            //过滤最后一个字段为空的情况  防止 header[9] 数组越界
            if (arrs[0].endsWith("_")) {
                continue;
            }
            if (header.length < 10) {
                continue;
            }
            for (int i = 0; i < steps.length; i++) {
                String[] step = steps[i].split("~");
                if (step.length < 5) {
                    continue;
                }
                Object result = new Object[]{header[1], header[9], step[0], Integer.valueOf(step[4]) - Integer.valueOf(step[3])};
                forward(result);
            }

        }

    }

    /**
     * avoid hitting this exception:  Error in query: No handler for UDF/UDAF/UDTF
     */
    @Override
    public StructObjectInspector initialize(ObjectInspector[] args) throws UDFArgumentException {
        if (args.length != 1) {
            throw new UDFArgumentLengthException("xxx  takes only one argument");
        }
        if (args[0].getCategory() != ObjectInspector.Category.PRIMITIVE) {
            throw new UDFArgumentException("xxx  takes string as a parameter");
        }

        ArrayList<String> fieldNames = new ArrayList<String>();
        ArrayList<ObjectInspector> fieldOIs = new ArrayList<ObjectInspector>();
        fieldNames.add("moves");
        fieldOIs.add(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
        fieldNames.add("left_moves");
        fieldOIs.add(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
        fieldNames.add("mubiao");
        fieldOIs.add(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
        fieldNames.add("left_num");
        fieldOIs.add(PrimitiveObjectInspectorFactory.javaIntObjectInspector);
        return ObjectInspectorFactory.getStandardStructObjectInspector(fieldNames, fieldOIs);
    }

}

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