用GSON解析Android JSON崩溃：LinkedTreeMap不能转换为对象

Question

java.lang.ClassCastException: com.google.gson.internal.LinkedTreeMap cannot be cast to appuccino.simplyscan.Objects.Folder
            at appuccino.simplyscan.Extra.DocumentAdapter.getView(DocumentAdapter.java:117)

Folder folder = folderList.get(position);

//folderList is a List<Folder> folderList = new ArrayList<>();
folderList.add(0, newFolder);
Gson gson = new Gson();
String newFoldersJson = gson.toJson(folderList);
PrefManager.putString(PrefManager.FOLDER_JSON, newFoldersJson);

 public static List<Folder> loadFolders(MainActivity main){
        //JSON containing a list of folder objects
        String foldersJSON = PrefManager.getString(PrefManager.FOLDER_JSON, "");
        if(!foldersJSON.isEmpty()){
            Gson gson = new Gson();
            List<Folder> folderList = gson.fromJson(foldersJSON, List.class);
            return folderList;
        }

        return new ArrayList<>();
    }

public class Folder {
    private String name;
    private List<String> docNameList;
    private transient List<Document> docList;

    public Folder(String n) {
        name = n;
        docList = new ArrayList<>();
        docNameList = new ArrayList<>();
    }

}

Answer 1

不是对你问题的回答，而是一个建议。我最近也在尝试在Android中使用json，并研究了很多关于使用jackson还是GSON的问题。似乎杰克逊有两个优点：

1. 杰克逊的表现优于GSON。
2. 如果在服务器端使用相同的方法，则可以获得一致性。

参考:[be-lazy-profaction-android][1]http://java.dzone.com/articles/be-lazy-profaction-android