static void buildJSONString(StringBuilder sb, Object o, ObjectInspector oi, String nullStr) {
switch (oi.getCategory()) {
case PRIMITIVE:
{
PrimitiveObjectInspector poi = (PrimitiveObjectInspector) oi;
if (o == null) {
sb.append(nullStr);
} else {
switch (poi.getPrimitiveCategory()) {
case BOOLEAN:
{
boolean b = ((BooleanObjectInspector) poi).get(o);
sb.append(b ? "true" : "false");
break;
}
case BYTE:
{
sb.append(((ByteObjectInspector) poi).get(o));
break;
}
case SHORT:
{
sb.append(((ShortObjectInspector) poi).get(o));
break;
}
case INT:
{
sb.append(((IntObjectInspector) poi).get(o));
break;
}
case LONG:
{
sb.append(((LongObjectInspector) poi).get(o));
break;
}
case FLOAT:
{
sb.append(((FloatObjectInspector) poi).get(o));
break;
}
case DOUBLE:
{
sb.append(((DoubleObjectInspector) poi).get(o));
break;
}
case STRING:
{
sb.append('"');
sb.append(escapeString(((StringObjectInspector) poi).getPrimitiveJavaObject(o)));
sb.append('"');
break;
}
case CHAR:
{
sb.append('"');
sb.append(
escapeString(
((HiveCharObjectInspector) poi).getPrimitiveJavaObject(o).toString()));
sb.append('"');
break;
}
case VARCHAR:
{
sb.append('"');
sb.append(
escapeString(
((HiveVarcharObjectInspector) poi).getPrimitiveJavaObject(o).toString()));
sb.append('"');
break;
}
case DATE:
{
sb.append('"');
sb.append(((DateObjectInspector) poi).getPrimitiveWritableObject(o));
sb.append('"');
break;
}
case TIMESTAMP:
{
sb.append('"');
sb.append(((TimestampObjectInspector) poi).getPrimitiveWritableObject(o));
sb.append('"');
break;
}
case BINARY:
{
BytesWritable bw = ((BinaryObjectInspector) oi).getPrimitiveWritableObject(o);
Text txt = new Text();
txt.set(bw.getBytes(), 0, bw.getLength());
sb.append(txt.toString());
break;
}
case DECIMAL:
{
sb.append(((HiveDecimalObjectInspector) oi).getPrimitiveJavaObject(o));
break;
}
default:
throw new RuntimeException("Unknown primitive type: " + poi.getPrimitiveCategory());
}
}
break;
}
case LIST:
{
ListObjectInspector loi = (ListObjectInspector) oi;
ObjectInspector listElementObjectInspector = loi.getListElementObjectInspector();
List<?> olist = loi.getList(o);
if (olist == null) {
sb.append(nullStr);
} else {
sb.append(LBRACKET);
for (int i = 0; i < olist.size(); i++) {
if (i > 0) {
sb.append(COMMA);
}
buildJSONString(sb, olist.get(i), listElementObjectInspector, JSON_NULL);
}
sb.append(RBRACKET);
}
break;
}
case MAP:
{
MapObjectInspector moi = (MapObjectInspector) oi;
ObjectInspector mapKeyObjectInspector = moi.getMapKeyObjectInspector();
ObjectInspector mapValueObjectInspector = moi.getMapValueObjectInspector();
Map<?, ?> omap = moi.getMap(o);
if (omap == null) {
sb.append(nullStr);
} else {
sb.append(LBRACE);
boolean first = true;
for (Object entry : omap.entrySet()) {
if (first) {
first = false;
} else {
sb.append(COMMA);
}
Map.Entry<?, ?> e = (Map.Entry<?, ?>) entry;
buildJSONString(sb, e.getKey(), mapKeyObjectInspector, JSON_NULL);
sb.append(COLON);
buildJSONString(sb, e.getValue(), mapValueObjectInspector, JSON_NULL);
}
sb.append(RBRACE);
}
break;
}
case STRUCT:
{
StructObjectInspector soi = (StructObjectInspector) oi;
List<? extends StructField> structFields = soi.getAllStructFieldRefs();
if (o == null) {
sb.append(nullStr);
} else {
sb.append(LBRACE);
for (int i = 0; i < structFields.size(); i++) {
if (i > 0) {
sb.append(COMMA);
}
sb.append(QUOTE);
sb.append(structFields.get(i).getFieldName());
sb.append(QUOTE);
sb.append(COLON);
buildJSONString(
sb,
soi.getStructFieldData(o, structFields.get(i)),
structFields.get(i).getFieldObjectInspector(),
JSON_NULL);
}
sb.append(RBRACE);
}
break;
}
case UNION:
{
UnionObjectInspector uoi = (UnionObjectInspector) oi;
if (o == null) {
sb.append(nullStr);
} else {
sb.append(LBRACE);
sb.append(uoi.getTag(o));
sb.append(COLON);
buildJSONString(
sb, uoi.getField(o), uoi.getObjectInspectors().get(uoi.getTag(o)), JSON_NULL);
sb.append(RBRACE);
}
break;
}
default:
throw new RuntimeException("Unknown type in ObjectInspector!");
}
}
/**
* Use this if you need to have custom representation of top level null . (ie something other than
* 'null') eg, for hive output, we want to to print NULL for a null map object.
*
* @param o Object
* @param oi ObjectInspector
* @param nullStr The custom string used to represent null value
* @return
*/
public static String getJSONString(Object o, ObjectInspector oi, String nullStr) {
StringBuilder sb = new StringBuilder();
buildJSONString(sb, o, oi, nullStr);
return sb.toString();
}