Question

我有两个表User和Roles，一对一的关系如下所示。

User
_________________________________________
| Id  | user_name | full_name | creator |
_________________________________________
| 1   | a         | A         | a       |
| 2   | b         | B         | a       |
| 3   | c         | C         | a       |
| 4   | d         | D         | c       |
| 5   | e         | E         | c       |
| 6   | f         | F         | e       |
| 7   | g         | G         | e       |
| 8   | h         | H         | e       |
| 9   | i         | I         | e       |
|10   | j         | J         | i       |
_________________________________________

Roles
_______________________________________
| id | user_mgmt | others | user_id |
_______________________________________
| 1  | 1        | 1      | 1           |
| 2  | 0        | 1      | 2           |
| 3  | 1        | 0      | 3           |
| 4  | 0        | 1      | 4           |
| 5  | 1        | 1      | 5           |
| 6  | 0        | 1      | 6           |
| 7  | 0        | 0      | 7           |
| 8  | 0        | 0      | 8           |
| 9  | 1        | 0      | 9           |
________________________________________

Roles表格有boolean个列，因此如果User具有user_mgmt个角色，则可以添加多个用户（用户可以添加多少个用户）定）。我想获取用户和他的子用户创建的所有用户（a是父级，c是a的子级，e是c的子级）。

以下是我获取用户的代码

public void loadUsers(){
  List<Users> users = new ArrayList<>();

  String creator = user.getUserName();
  List<Users> createdUsers = userService.getUsersByCreator(creator);
  for(Users user : createdUsers) {
    Roles role = createdUsers.getRoles();
    if(role.isEmpMgnt()){
      users.add(user);
      loadUsers();
    }
  }
}

这给了我一个堆栈溢出错误。如果我不以递归方式调用loadUsers()，则只返回单个子结果。那有什么解决方案吗？感谢您提前提供任何帮助。

Answer 1

这会导致堆栈溢出错误，因为12-02 00:32:50.429 3720-4954/? E/Parcel: Class not found when unmarshalling: com.facebook.gdp.LightWeightLoginParameters java.lang.ClassNotFoundException: com.facebook.gdp.LightWeightLoginParameters at java.lang.Class.classForName(Native Method) at java.lang.Class.forName(Class.java:400) at android.os.Parcel.readParcelableCreator(Parcel.java:2517) at android.os.Parcel.readParcelable(Parcel.java:2471) at android.os.Parcel.readValue(Parcel.java:2374) at android.os.Parcel.readArrayMapInternal(Parcel.java:2727) at android.os.BaseBundle.unparcel(BaseBundle.java:269) at android.os.BaseBundle.getString(BaseBundle.java:992) at android.content.Intent.getStringExtra(Intent.java:6702) at com.android.server.am.ActivityStarter.startActivityLocked(ActivityStarter.java:336) at com.android.server.am.ActivityStarter.startActivityMayWait(ActivityStarter.java:1094) at com.android.server.am.ActivityManagerService.startActivityAsUser(ActivityManagerService.java:5822) at com.android.server.am.ActivityManagerService.startActivity(ActivityManagerService.java:5627) at android.app.ActivityManagerNative.onTransact(ActivityManagerNative.java:176) at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:3612) at android.os.Binder.execTransact(Binder.java:573) Caused by: java.lang.ClassNotFoundException: com.facebook.gdp.LightWeightLoginParameters at java.lang.Class.classForName(Native Method) at java.lang.BootClassLoader.findClass(ClassLoader.java:1346) at java.lang.BootClassLoader.loadClass(ClassLoader.java:1406) at java.lang.ClassLoader.loadClass(ClassLoader.java:312) at java.lang.Class.classForName(Native Method) at java.lang.Class.forName(Class.java:400) at android.os.Parcel.readParcelableCreator(Parcel.java:2517) at android.os.Parcel.readParcelable(Parcel.java:2471) at android.os.Parcel.readValue(Parcel.java:2374) at android.os.Parcel.readArrayMapInternal(Parcel.java:2727) at android.os.BaseBundle.unparcel(BaseBundle.java:269) at android.os.BaseBundle.getString(BaseBundle.java:992) at android.content.Intent.getStringExtra(Intent.java:6702) at com.android.server.am.ActivityStarter.startActivityLocked(ActivityStarter.java:336) at com.android.server.am.ActivityStarter.startActivityMayWait(ActivityStarter.java:1094) at com.android.server.am.ActivityManagerService.startActivityAsUser(ActivityManagerService.java:5822) at com.android.server.am.ActivityManagerService.startActivity(ActivityManagerService.java:5627) at android.app.ActivityManagerNative.onTransact(ActivityManagerNative.java:176) at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:3612) at android.os.Binder.execTransact(Binder.java:573) Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available 12-02 00:32:50.429 3720-4954/? W/Bundle: Failed to parse Bundle, but defusing quietly android.os.BadParcelableException: ClassNotFoundException when unmarshalling: com.facebook.gdp.LightWeightLoginParameters at android.os.Parcel.readParcelableCreator(Parcel.java:2545) at android.os.Parcel.readParcelable(Parcel.java:2471) at android.os.Parcel.readValue(Parcel.java:2374) at android.os.Parcel.readArrayMapInternal(Parcel.java:2727) at android.os.BaseBundle.unparcel(BaseBundle.java:269) at android.os.BaseBundle.getString(BaseBundle.java:992) at android.content.Intent.getStringExtra(Intent.java:6702) at com.android.server.am.ActivityStarter.startActivityLocked(ActivityStarter.java:336) at com.android.server.am.ActivityStarter.startActivityMayWait(ActivityStarter.java:1094) at com.android.server.am.ActivityManagerService.startActivityAsUser(ActivityManagerService.java:5822) at com.android.server.am.ActivityManagerService.startActivity(ActivityManagerService.java:5627) at android.app.ActivityManagerNative.onTransact(ActivityManagerNative.java:176) at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:3612) at android.os.Binder.execTransact(Binder.java:573)有创建者a。所以你有一个无限循环的用户a。对于a，您应将创建者设置为a或跳过代码中的自引用。此外，您应该将当前用户传递给null方法，并且只读取由其创建的用户。喜欢

loadUsers()

并且仅处理由该创建者创建的用户。在这里

public void loadUsers(String creator)

什么是用户？你应该使用创作者。问题是你如何获得初始创作者。可能初始创建者应该是创建者为空的用户。

迭代java中的列表列表

1 个答案: