PlayFrameWork与DataTables空指针异常

Question

我试图从数据库中提取数据并将其发布到数据表中。

我的控制器如下

public static Result vwFarmerslist(){
        UserAccount user = isLoggedIn();
        if (user == null || user.username == null ){
            return redirect(controllers.routes.Application.login());
        } else {

            /**
            Get needed params
            */

            Map<String, String[]> params = request().queryString();

            /**Get Total Records*/

            Integer iTotalFarmers = Farmers.find.findRowCount();
            Logger.info ("Total Farmers: "+iTotalFarmers);
            Logger.info("params+ "+params);
            String filter = params.get("search[value]")[0];

            Logger.info ("Filter : "+filter);

            //get page Size
            Integer pageSize = Integer.valueOf(params.get("length")[0]);
            Integer page = Integer.valueOf(params.get("start")[0]) / pageSize;

            /**
             *** Get sorting order and column
             */
            String sortBy = "name";
            String order = params.get("order[0][dir]")[0];
            switch (Integer.valueOf(params.get("order[0][column]")[0])) {
                case 0 : sortBy = "name"; break;
                case 1 : sortBy = "idno"; break;
                //case 2 : sortBy = "regions"; break;
                case 2 : sortBy = "mobile"; break;
            }

            /**
             * Get data from db
             */
            Page<Farmers> vwfarmerslistPage = Farmers.find.where(
                    Expr.or(
                            Expr.ilike("name", "%" + filter + "%"),
                            Expr.or(
                                Expr.ilike("idno", "%" + filter + "%"),
                                Expr.ilike("mobile", "%" + filter + "%")
                                    //Expr.ilike("regions", "%" + filter + "%"),

                            )
                    )
            ).orderBy(sortBy + " " + order + ", id " + order)
                            .findPagingList(pageSize).setFetchAhead(false)
                            .getPage(page);

            Integer iTotalFarmersRecord = vwfarmerslistPage.getTotalRowCount();

            /**
             * Construct JSON Return Object
             *
             */
            ObjectNode result = Json.newObject();
            result.put("draw", Integer.valueOf(params.get("draw")[0]));
            result.put("recordsTotalFarmers",iTotalFarmers);
            result.put("recordsFilter",iTotalFarmersRecord);

            ArrayNode arrayNode = result.putArray("data");
            for (Farmers c : vwfarmerslistPage.getList()){
                ObjectNode row = Json.newObject();
                row.put("0",c.toString());
                row.put("1",c.idno);
                row.put("2",c.mobile);
                arrayNode.add(row);
                Logger.info("Farmers array: " +arrayNode);

            }

            return ok(result);
        }
    }

我的模型如下

public class Farmers extends Model {
    @Id
    public Long id;

    @Constraints.Required
    public String fname="";

    public String mname="";

    @Constraints.Required
    public String lname="";

    @Constraints.Required
    public String idno ="";

    @Constraints.Required
    public String mobile = "";

    public String bankaccountno="";

    public String bankname="";

    @OneToOne
    public Regions regions;

    @Formats.DateTime(pattern = "yyyy-mm-dd hh:mm:ss")
    public Date createdon = new Date();

    @OneToOne
    public UserAccount user;

    @OneToOne
    public UserAccount updateduser;

    public static Finder<Long, Farmers> find = new Finder<Long, Farmers>(Long.class,Farmers.class);

    /**public static Farmers findByIdno(String idno){

        return Farmers.find.where().eq("idno",idno).findUnique();
    }

    public static Map<String, String> options(){
        LinkedHashMap<String, String> options = new LinkedHashMap<String, String>();
        for(Farmers c:Farmers.find.orderBy("idno").findList()){
            options.put(String.valueOf(c.id), c.idno);
        }

        return options;
    }*/

    public static List<Farmers> findall(){

        return find.all();

    }

    public String toString(){

       String name = fname+" "+mname+" "+lname;
        return name;
    }


}

当我运行代码时，我得到一个空指针异常，如下面的调试所示

play.api.Application$$anon$1: Execution exception[[NullPointerException: null]]
    at play.api.Application$class.handleError(Application.scala:296) ~[play_2.11-2.3.6.jar:2.3.6]
    at play.api.DefaultApplication.handleError(Application.scala:402) [play_2.11-2.3.6.jar:2.3.6]
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3$$anonfun$applyOrElse$4.apply(PlayDefaultUpstreamHandler.scala:320) [play_2.11-2.3.6.jar:2.3.6]
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3$$anonfun$applyOrElse$4.apply(PlayDefaultUpstreamHandler.scala:320) [play_2.11-2.3.6.jar:2.3.6]
    at scala.Option.map(Option.scala:145) [scala-library-2.11.1.jar:na]
Caused by: java.lang.NullPointerException: null
    at controllers.ContractCtrl.vwFarmerslist(ContractCtrl.java:66) ~[classes/:na]
    at Routes$$anonfun$routes$1$$anonfun$applyOrElse$9$$anonfun$apply$9.apply(routes_routing.scala:361) ~[classes/:na]
    at Routes$$anonfun$routes$1$$anonfun$applyOrElse$9$$anonfun$apply$9.apply(routes_routing.scala:361) ~[classes/:na]
    at play.core.Router$HandlerInvokerFactory$$anon$4.resultCall(Router.scala:264) ~[play_2.11-2.3.6.jar:2.3.6]
    at play.core.Router$HandlerInvokerFactory$JavaActionInvokerFactory$$anon$15$$anon$1.invocation(Router.scala:255) ~[play_2.11-2.3.6.jar:2.3.6]

我的农民桌也不是空的。它有两个左右的条目。