public void extract(JSONPath path, DefaultJSONParser parser, Context context) {
            JSONLexerBase lexer = (JSONLexerBase) parser.lexer;
            if (lexer.seekArrayToItem(index)
                    && context.eval)
            {
                context.object = parser.parse();
            }
        }
@since 1.2.51
@param json
@param path
@return
src/main/java/com/alibaba/fastjson/JSONPath.java