gson解析实体类报错，

com.google.gson.JsonSyntaxException: java.lang.NumberFormatException: Expected an int but was 640600000003 at line 1 column 61 path $.pscode

at com.google.gson.internal.bind.TypeAdapters$7.read(TypeAdapters.java:241)

at com.google.gson.internal.bind.TypeAdapters$7.read(TypeAdapters.java:231)

at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:103)

at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:196)

at com.google.gson.Gson.fromJson(Gson.java:810)

at com.google.gson.Gson.fromJson(Gson.java:775)

at com.google.gson.Gson.fromJson(Gson.java:724)

at 

这是什么原因导致的呢？