如何使用Hibernate在Spring MVC中保存模型返回查看的列表

Question

Controller

 @RequestMapping(value = "/chartofaccount", method = RequestMethod.GET)
public String getChartofAccount(Model model) {

    try {

        List CoaCategoryList = new ArrayList();
        COACategoriesModel obj;
        List<COACategoriesModel> getCoaCategoryList = coaCategoriesService
                .getAllCOACategories();

        if (getCoaCategoryList.size() > 0) {
            for (int i = 0; i < getCoaCategoryList.size(); i++) {

                obj = getCoaCategoryList.get(i);
                CoaCategoryList.add(obj.getId());
                CoaCategoryList.add(obj.getName());
                model.addAttribute("list", CoaCategoryList);

            }
        }

    } catch (Exception ex) {
        log.error("Exception.." + ex);

    }

    return "fin/coa";
}

fin/coa.jsp

<ct:Select setIdentity="coaCategoryId" list="${list}" selected="0" />

the above list successfully populate, In my custom tag.

but 

Another controller

    @RequestMapping(value = "/addCoaMaintenance", method = RequestMethod.POST)
public String addCoaCategory(
        @RequestParam("mainAccount") long mainAccount,
        @RequestParam("subAccount") long subAccount,
        @RequestParam("accountName") String accountName,
        @RequestParam("coaCategoryId") long coaCategoryId,
        @RequestParam("postingType") int postingType,
        @RequestParam("typicalBalance") int typicalBalance,
        @RequestParam("isActive") int isActive,
        Model model) {

     Date sysdate = null;
     String Message="";

     try{

     sysdate = new Date();

     Message="Operation Fail!";
     COAMaintenanceModel coaMaintenanceModel= new COAMaintenanceModel(mainAccount, subAccount, accountName, coaCategoryId, postingType, typicalBalance, isActive, GetSessionValue.getSysUserId(), GetSessionValue.getSysUserIp(), sysdate, 0);
     coaMaintenanceService.AddCOAMaintenance(coaMaintenanceModel);

     Message="Account Save Successfully";
     model.addAttribute("result_success", Message);

     }catch(Exception ex){
         log.error("Exception.."+ex);
         model.addAttribute("result_fail", Message);
     }



     return "fin/coa";

    }

as the this second one controller return fin/coa.jsp , list is null. how to control this? I am using spring Mvc + hibernate. How to make the first controller list make available, until I required.

Answer 1

I'm not sure I understood the problem correctly, however, the way I see it, you didn't include the list in the model in the second handler method / controller.

Are both handler methods (@RequestMapping annotated methods) inside the same controller class? If yes, one solution is to add @ModelAttribute on a metod that populates the list. Eg you would add the following:

@ModelAttribute("list")
public List getCategoryList() {
    List CoaCategoryList = new ArrayList();
    COACategoriesModel obj;
    List<COACategoriesModel> getCoaCategoryList = coaCategoriesService
            .getAllCOACategories();
    // this if is unncessary
    // if (getCoaCategoryList.size() > 0) {
    for (int i = 0; i < getCoaCategoryList.size(); i++) {
        obj = getCoaCategoryList.get(i);
        CoaCategoryList.add(obj.getId());
        CoaCategoryList.add(obj.getName());            
    }    
    return CoaCategoryList;
}

This will make attribute "list" available in models of all requests in this controller and you will not need to add it via model.addAttribute(...).

Other solution would be to populate the list manually in each handler and add it manually to the model (you already do that for the first handler method, but not in the second one).

If the handler methods are not inside same controller class than you again need to make sure list is in the model before rendering the view (either by making both controller classes extending a common abstract controller were you add functionality to populate the list, or by manually populating the model, or some other way).

PS. Also, consider taking a look at "Code Conventions for the Java Programming Language" (eg variable names in Java usually start with lowercase letter to distinguish them form class names) http://www.oracle.com/technetwork/java/codeconv-138413.html

Answer 2

One solution : test if your list is null or empty

<c:if test="${not empty list}">
   <ct:Select setIdentity="coaCategoryId" list="${list}" selected="0" />
</c:if>