在我的servlet中,我有以下代码:
response.setContentType("application/json");//set json content type PrintWriter out = response.getWriter(); EntityManagerFactory emf=Persistence.createEntityManagerFactory("webPU"); GpsJpaController gjc=new GpsJpaController(emf); java.util.List<Gps> listGps=gjc.findGpsEntities();//retrieve the list of GPS from DB Gson gson=new Gson(); String json=gson.toJson(listGps); //convert List<Gps> to json out.println(json);
使用以下代码从ajax返回响应:
$.ajax({ type: "GET", url: "getInfoGeoActive", dataType: 'json', error: function(xhr, ajaxOptions, thrownError){ $("#content").empty().append("* Error from server cause: "+thrownError).addClass("error"); } , success:function(data){$("#content").empty().append(data);} });
当我运行代码时,我仍然收到以下错误(来自ajax):
Error from server cause:Internal Servlet Error
我还尝试List<Gps>在没有ajax的同一java页面中显示序列化对象,如下所示:
List<Gps>
EntityManagerFactory emf=Persistence.createEntityManagerFactory("JavaApplication21PU"); GpsJpaController gjc=new GpsJpaController(emf); java.util.List<Gps> listGps=gjc.findGpsEntities(); Gson gson=new Gson(); String json=gson.toJson(listGps); System.out.println(json);
我收到此错误:
Exception in thread "main" java.lang.StackOverflowError at java.lang.StrictMath.floorOrCeil(StrictMath.java:355) at java.lang.StrictMath.floor(StrictMath.java:340) at java.lang.Math.floor(Math.java:424) at sun.misc.FloatingDecimal.dtoa(FloatingDecimal.java:620) at sun.misc.FloatingDecimal.<init>(FloatingDecimal.java:459) at java.lang.Double.toString(Double.java:196) at java.lang.Double.toString(Double.java:633) at com.google.gson.stream.JsonWriter.value(JsonWriter.java:441) at com.google.gson.Gson$4.write(Gson.java:270) at com.google.gson.Gson$4.write(Gson.java:255)
请帮忙!
编辑 : 此问题的最终解决方案
由于无限递归,发生 Exception 。您可能需要彻底检查代码,以防任何意外的递归。