ジャクソンとのMoodle Webサービスからjsonを非直列化

Question

私はMoodle REST APIの呼び出しから得られたJSONオブジェクトを解析する必要があります。私が取得JSON応答は次のとおりです。

{"users":[{"id":2,"username":"admin","firstname":"Amministratore","lastname":"Utente","fullname":"Amministratore Utente","email":"email@address.com","department":"","firstaccess":1475831148,"lastaccess":1477493148,"description":"","descriptionformat":1,"profileimageurlsmall":"http:\/\/vmoodle.local\/theme\/image.php\/clean\/core\/1475846316\/u\/f2","profileimageurl":"http:\/\/vmoodle.local\/theme\/image.php\/clean\/core\/1475846316\/u\/f1","preferences":[{"name":"auth_manual_passwordupdatetime","value":"1475831184"},{"name":"email_bounce_count","value":"1"},{"name":"email_send_count","value":"1"},{"name":"_lastloaded","value":1477561370}]}],"warnings":[]} 

私はPOJOに、このJSONをマッピングしたいと思いますので、私は、2つのクラスを書いた：

public class MoodleUser { 

     public MoodleUser() { 
     } 

     private int id; 
     private String username; 

     /** 
     * @return the id 
     */ 
     public int getId() { 
      return id; 
     } 

     /** 
     * @param id the id to set 
     */ 
     public void setId(int id) { 
      this.id = id; 
     } 

     /** 
     * @return the username 
     */ 
     public String getUsername() { 
      return username; 
     } 

     /** 
     * @param username the username to set 
     */ 
     public void setUsername(String username) { 
      this.username = username; 
     } 

    } 

    public class MoodleUsers { 

     public MoodleUsers() { 

     } 

     private List<MoodleUser> users; 

     /** 
     * @return the users 
     */ 
     public List<MoodleUser> getUsers() { 
      return users; 
     } 

     /** 
     * @param users the users to set 
     */ 
     public void setUsers(List<MoodleUser> users) { 
      this.users = users; 
     } 

    } 

をそして私が呼ぶ：

MoodleUsers response = oMapper.readValue(result, MoodleUsers.class); 

次のエラーを報告する例外が表示されます。

com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of mypackage.lms.MoodleClientRest$MoodleUsers: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?) 
at [Source: {"users":[{"id":12,"username":"userok","firstname":"Nome test","lastname":"Cognome test","fullname":"Nome test Cognome test","email":"email@test.it","department":"","idnumber":"cftest","firstaccess":0,"lastaccess":0,"description":"","descriptionformat":1,"country":"IT","profileimageurlsmall":"http:\/\/vmoodle.local\/theme\/image.php\/clean\/core\/1475846316\/u\/f2","profileimageurl":"http:\/\/vmoodle.local\/theme\/image.php\/clean\/core\/1475846316\/u\/f1"}],"warnings":[]} 
; line: 1, column: 2] 
    at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:261) 
    at com.fasterxml.jackson.databind.DeserializationContext.instantiationException(DeserializationContext.java:1456) 
    at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1012) 
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1203) 
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:314) 
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:148) 
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3789) 
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2833) 

私はすでにpojoの中にデフォルトコンストラクタを持っているので、どこに問題があるのか​​理解できません。助言がありますか？ ありがとうございます。

excpetionで

Answer 1

クラスの名前：mypackage.lms.MoodleClientRest$MoodleUsersはMoodleUsersがMoodleClientRestの内部クラスであり、その場合には、それははジャクソンが正常にオブジェクトをインスタンス化するためには、公共静的であるとを持っていることを示唆しています。