JSONオブジェクトをGsonで解析するとNull値が返されます

Question

私はJSONとそのメインクラスをAndroidプロジェクトに持っています。 GSONでデータを解析しようとすると、以下のエラーが表示されます。 抽出したデータですが、何らかのエラーがあります。 提案？事前に感謝

Attempt to invoke interface method 'java.lang.Object java.util.List.get(int)' on a null object reference 

コード

test3[] netsClass = new Gson().fromJson(String.valueOf(jsonObj),test3[].class); 
String objstr = netsClass[1].getNet().get(1).getDevice().get(1).getPlants().getPlant1().getDescription(); 
Log.d(TAG, "onCreate: STATUS "+ objstr); 

は、これはあなたがする必要がある必要がありますすべてが（jsonStringが含まれていると仮定している私のJSON配列

{ 
"Net": [ 
    { 
     "-IdAliasZone": "id1", 
     "-FullDomain": "domain", 
     "-PubIp": "IP", 
     "-RemMode": "0", 
     "Device": [ 
      { 
       "-IdAliasDevice": "id2", 
       "-Description": "device2", 
       "-IdType": "1", 
       "-Type": "2", 
       "-LocalUrl": "ip" 
      }, 
      { 
       "-IdAliasDevice": "id3", 
       "-Description": "device3", 
       "-IdType": "2", 
       "-Type": "64", 
       "-LocalUrl": "url", 
       "-RemotePort": "33", 
       "-Mac": "00:00:00:00", 
       "-Status": "asd", 
       "-Version": "1", 
       "-Uptime": "1234", 
       "Plants": { 
        "Plant1": { 
         "-Description": "1", 
         "-Enable": "1" 
        }, 
        "Plant2": { 
         "-Description": "2", 
         "-Enable": "1" 
        }, 
        "Plant3": { 
         "-Description": "3", 
         "-Enable": "1" 
        }, 
        "Plant4": { 
         "-Description": "4", 
         "-Enable": "1" 
        } 
       } 
      } 
     ] 
    } 
    ] 
} 

TEST3クラス

public class test3 implements Serializable { 

private List<NetClass> Net; 

public List<NetClass> getNet() { 
    return Net; 
} 

public void setNet(List<NetClass> Net) { 
    this.Net = Net; 
} 

public static class NetClass { 
    @SerializedName("-IdAliasZone") 
    private String IdAliasZone; 
    @SerializedName("-FullDomain") 
    private String FullDomain; 
    @SerializedName("-PubIp") 
    private String PubIp; 
    @SerializedName("-RemMode") 
    private String RemMode; 


    private List<DeviceClass> Device; 

    public String getIdAliasZone() { 
     return IdAliasZone; 
    } 

    public void setIdAliasZone(String IdAliasZone) { 
     this.IdAliasZone = IdAliasZone; 
    } 

    public String getFullDomain() { 
     return FullDomain; 
    } 

    public void setFullDomain(String FullDomain) { 
     this.FullDomain = FullDomain; 
    } 

    public String getPubIp() { 
     return PubIp; 
    } 

    public void setPubIp(String PubIp) { 
     this.PubIp = PubIp; 
    } 

    public String getRemMode() { 
     return RemMode; 
    } 

    public void setRemMode(String RemMode) { 
     this.RemMode = RemMode; 
    } 

    public List<DeviceClass> getDevice() { 
     return Device; 
    } 

    public void setDevice(List<DeviceClass> Device) { 
     this.Device = Device; 
    } 

    public static class DeviceClass { 
     @SerializedName("-IdAliasDevice") 
     private String IdAliasDevice; 
     @SerializedName("-Description") 
     private String Description; 
     @SerializedName("-IdType") 
     private String IdType; 
     @SerializedName("-Type") 
     private String Type; 
     @SerializedName("-LocalUrl") 
     private String LocalUrl; 
     @SerializedName("-RemotePort") 
     private String RemotePort; 
     @SerializedName("-Mac") 
     private String Mac; 
     @SerializedName("-Status") 
     private String Status; 
     @SerializedName("-Version") 
     private String Version; 
     @SerializedName("-Uptime") 
     private String Uptime; 


     private PlantsClass Plants; 

     public String getIdAliasDevice() { 
      return IdAliasDevice; 
     } 

     public void setIdAliasDevice(String IdAliasDevice) { 
      this.IdAliasDevice = IdAliasDevice; 
     } 

     public String getDescription() { 
      return Description; 
     } 

     public void setDescription(String Description) { 
      this.Description = Description; 
     } 

     public String getIdType() { 
      return IdType; 
     } 

     public void setIdType(String IdType) { 
      this.IdType = IdType; 
     } 

     public String getType() { 
      return Type; 
     } 

     public void setType(String Type) { 
      this.Type = Type; 
     } 

     public String getLocalUrl() { 
      return LocalUrl; 
     } 

     public void setLocalUrl(String LocalUrl) { 
      this.LocalUrl = LocalUrl; 
     } 

     public String getRemotePort() { 
      return RemotePort; 
     } 

     public void setRemotePort(String RemotePort) { 
      this.RemotePort = RemotePort; 
     } 

     public String getMac() { 
      return Mac; 
     } 

     public void setMac(String Mac) { 
      this.Mac = Mac; 
     } 

     public String getStatus() { 
      return Status; 
     } 

     public void setStatus(String Status) { 
      this.Status = Status; 
     } 

     public String getVersion() { 
      return Version; 
     } 

     public void setVersion(String Version) { 
      this.Version = Version; 
     } 

     public String getUptime() { 
      return Uptime; 
     } 

     public void setUptime(String Uptime) { 
      this.Uptime = Uptime; 
     } 

     public PlantsClass getPlants() { 
      return Plants; 
     } 

     public void setPlants(PlantsClass Plants) { 
      this.Plants = Plants; 
     } 

     public static class PlantsClass { 


      private Plant1Class Plant1; 
      private Plant1Class Plant2; 
      private Plant1Class Plant3; 
      private Plant1Class Plant4; 

      public Plant1Class getPlant1() { 
       return Plant1; 
      } 

      public void setPlant1(Plant1Class Plant1) { 
       this.Plant1 = Plant1; 
      } 

      public Plant1Class getPlant2() { 
       return Plant2; 
      } 

      public void setPlant2(Plant1Class Plant2) { 
       this.Plant2 = Plant2; 
      } 

      public Plant1Class getPlant3() { 
       return Plant3; 
      } 

      public void setPlant3(Plant1Class Plant3) { 
       this.Plant3 = Plant3; 
      } 

      public Plant1Class getPlant4() { 
       return Plant4; 
      } 

      public void setPlant4(Plant1Class Plant4) { 
       this.Plant4 = Plant4; 
      } 

      public static class Plant1Class { 
       @SerializedName("-Description") 
       private String Description; 
       @SerializedName("-Enable") 
       private String Enable; 

       public String getDescription() { 
        return Description; 
       } 

       public void setDescription(String Description) { 
        this.Description = Description; 
       } 

       public String getEnable() { 
        return Enable; 
       } 

       public void setEnable(String Enable) { 
        this.Enable = Enable; 
       } 
      } 
     } 
    } 
} 
} 

Answer 1

ですそのあなたは上記に含まれているjson）。

test3 netsClass = new Gson().fromJson(jsonString, test3.class);

上記のあなたの割り当てはまたに変更します：JSONがいっぱいでない

String objstr = netsClass.getNet().get(0).getDevice().get(1).getPlants().getPlant1().getDescription();