GSON解析JAVABEAN返回空值

{
"ErrorMessage": null,
"ResponseData": {
"Data": [
{
"DeviceTypeConfigId": "1",
"DeviceTypeName": "1",
"SensorInfos": [
{
"SensorCode": "AirTemperature",
"SensorConfigId": 1,
"SensorName": "空气温度",
"ValueType": "Value"
},
{
"SensorCode": "AirHumidity",
"SensorConfigId": 2,
"SensorName": "空气湿度",
"ValueType": "Value"
},
{
"SensorCode": "CarbonDioxide",
"SensorConfigId": 3,
"SensorName": "二氧化碳",
"ValueType": "Value"
},
{
"SensorCode": "Radiance",
"SensorConfigId": 4,
"SensorName": "辐射强度",
"ValueType": "Value"
},
{
"SensorCode": "SoilTemperature",
"SensorConfigId": 5,
"SensorName": "土壤温度",
"ValueType": "Value"
},
{
"SensorCode": "SoilHumidity",
"SensorConfigId": 6,
"SensorName": "土壤湿度",
"ValueType": "Value"
}
]
}
],
"Index": 1,
"PageSize": 1,
"TotalCount": 8
}
}
这是服务器返回的JSON数据，在转换的时候我是这样写的

jsonObject = new JSONObject(responseInfo.result);
JsonsRootBean jsonsRootBean=gson.fromJson(responseInfo.result, JsonsRootBean.class);
.Responsedata res=jsonsRootBean.getResponsedata();
System.out.println("--res-----"+res);
控制台中显示res 返回的值为NULL，请问这是为什么呢，实体类我已经写好了

转换之前你先打印一下responseInfo.result有没有数据，如果有数据你再看看你的实体类写的对不对啊。我直接拿的你上面的json数据测试是有数据的。

实体类有问题，下面是按你JSON数据写的一个实体类，get、set自行添加。

public class JsonsRootBean {
private String ErrorMessage;
private Data ResponseData;

public class Data {
    private List<DataList> Data;
    private int Index;
    private int PageSize;
    private int TotalCount;
}

public class DataList {
    private String DeviceTypeConfigId;
    private String DeviceTypeName;
    private List<SensorInfosList> SensorInfos;
}

public class SensorInfosList {
    private String SensorCode;
    private int SensorConfigId;
    private String SensorName;
    private String ValueType;
}

}

public class Sensorinfos {
private String sensorcode;
private int sensorconfigid;
private String sensorname;
private String valuetype;
public void setSensorcode(String sensorcode) {
this.sensorcode = sensorcode;
}
public String getSensorcode() {
return sensorcode;
}

public void setSensorconfigid(int sensorconfigid) {
     this.sensorconfigid = sensorconfigid;
 }
 public int getSensorconfigid() {
     return sensorconfigid;
 }

public void setSensorname(String sensorname) {
     this.sensorname = sensorname;
 }
 public String getSensorname() {
     return sensorname;
 }

public void setValuetype(String valuetype) {
     this.valuetype = valuetype;
 }
 public String getValuetype() {
     return valuetype;
 }

}