我是新来的Hiveudtf。我需要在udtf中传递字符串值作为parameter，返回的列应该是arraylist。
我编写了以下代码：

public StructObjectInspector initialize(ObjectInspector[] arg0)
        throws UDFArgumentException {
        ArrayList<String> fieldNames = new ArrayList<String>();
        ArrayList<ObjectInspector> fieldOIs = new ArrayList<ObjectInspector>();
        fieldNames.add("col1");
        stringOI = (PrimitiveObjectInspector) arg0[0];
       listOi=(ListObjectInspector) arg0[0];
        fieldOIs.add(listOi.getListElementObjectInspector());
        return ObjectInspectorFactory.getStandardStructObjectInspector(fieldNames, fieldOIs);
}

@Override
public void process(Object[] record) throws HiveException {
    // TODO Auto-generated method stub
     String document = (String) stringOI.getPrimitiveJavaObject(record[0]);
     if (document == null) {
          return;
        }
    firstColumn=(String) stringOI.getPrimitiveJavaObject(record[0]);
    secondColumn=(String) stringOI.getPrimitiveJavaObject(record[1]);
    if(outputMapper.containsKey(firstColumn))
    {

        ArrayList<String> tempList=new ArrayList<String>();
        tempList=outputMapper.get(firstColumn);
        tempList.add(secondColumn);
        outputMapper.put(firstColumn,tempList);
    }
    else
    {
            childVendorList=new ArrayList<String>();
            childVendorList.add(secondColumn);
            outputMapper.put(firstColumn,childVendorList);
    }
    forward(outputMapper.get(firstColumn));

}

}
我得到以下例外：
java.lang.classcastexception:org.apache.hadoop.hive.serde2.lazy.objectinspector.primitive.lazystringobjectinspector不能转换为org.apache.hadoop.hive.serde2.objectinspector.listobjectinspector
有人能帮忙吗？？？