Jackson conversion Generic list error java.util.LinkedHashMap cannot be cast to com.xxx

Use the code on StackOverflow to describe the problem:

  Objectmapper mapper = new Objectmapper ();    list<consultantdto> list = new arraylist<consultantdto> ();    try {        list = Mapper.readvalue (Con.getinputstream (), arraylist.class);    } catch (Jsongenerationexception e) {        e.printstacktrace ();    } catch (Jsonmappingexception e) {        e.printstacktrace ();    } catch (IOException e) {        e.printstacktrace ();    }

The conversion will not have an error, but it will throw an exception when getting the specific data:

System.out.println (list.get (0)); System.out.println (List.get (0). Getforename ()); return list;

<span style= "color: #FF0000;" ><strong>java.lang.classcastexception:java.util.linkedhashmap cannot is cast to Com.xxx.xxx.web.dto.rp.consultantdto</strong></span>

There is very little exception information.

Workaround:

list<consultantdto> myobjects =    mapper.readvalue (jsoninput, New typereference<list<consultantdto >> () {});

Jackson conversion Generic list error java.util.LinkedHashMap cannot be cast to com.xxx