当类对象可以在方法的参数中传递时,为什么要使用@Body注释?

在getLocation()方法中,如果只传递TableParameter对象,会有什么不同?

    public interface MasterAPI {
    @POST("Master/getLocation")
    public Call<List<LocationGetTab>> getLocation(@Body TableParameter 
    parameter);
    }

Class TableParameter定义如下:

    public class TableParameter {
    @SerializedName("State")
    int State;
    @SerializedName("district")
    int District;
    @SerializedName("LocType")
    String locType;

    public TableParameter(int district, int state, String locType) {
    District = district;
    State = state;
    this.locType = locType;
    }
    }