自定义genericUDF demo

package cn.com.dtmobile.hiveUdf;

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.GenericUDF;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.StringObjectInspector;

/**
 * 调整小区的格式
 * 460-00-394487-1 --> 394487_1
 */

public class SubstrCgi extends GenericUDF  {
    private transient StringObjectInspector allCgi;

    @Override
    public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {
        ObjectInspector a = arguments[0];
        if (arguments.length != 1) {
            throw new UDFArgumentLengthException(
                    "The operator 'SubstrCgi' accepts one arguments.");
        }
        this.allCgi = (StringObjectInspector) a;
        return PrimitiveObjectInspectorFactory.javaStringObjectInspector;
    }

    @Override
    public Object evaluate(DeferredObject[] arguments) throws HiveException {
        String cgi = allCgi.getPrimitiveJavaObject(arguments[0].get());
        if(null == cgi) {
            return null;
        }
        String[] s = cgi.toString().split("-");
        StringBuffer sb = new StringBuffer().append(s[2]).append("_").append(s[3]);
        return sb.toString();
    }

    @Override
    public String getDisplayString(String[] children) {
        return "Usage: SubstrCgi(String cgi)";
    }

//    public static void main(String[] args) throws Exception {
//        SubstrCgi sub = new SubstrCgi();
//        ObjectInspector stringOI = PrimitiveObjectInspectorFactory.javaStringObjectInspector;
//        sub.initialize(new ObjectInspector[]{stringOI});
//
////        String input1 = "460-00-394487-1";
//        String input = "460-00-396666-2";
//
//        Object result = sub.evaluate(new DeferredObject[]{new DeferredJavaObject(input)});
//        System.out.println(result.toString());
//        sub.close();
//    }

}