Spring表单:select - multiple默认不选择第一个选项

Question

我一直在做一个使用Spring表单标签库的Spring项目(http://www.springframework.org/tags/form)。

我使用一些多个选择框来指示一些选项(国家，工厂，…)
当我将整个列表传递给选择时-一切都很好:选择列表的第一个选项默认情况下被选中。但是，当用户来自特定国家时，将对列表进行过滤，只显示他所在的国家。在这种情况下，第一个元素默认不被选中。

JSP页面:

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<form:select path="countryValues" multiple="true" size="9" style="width:192px;" cssErrorClass="field-error">
    <form:options items="${command.countries}" itemValue="countryCode" itemLabel="correctDisplayString"/>                                       
</form:select>

Command.java

public List<CountryMaster> getCountries() {
    return countries;
}
public void setCountries(List<CountryMaster> countries) {
    this.countries = countries;
}

Controller.java

@RequestMapping(value = "/overview", method = RequestMethod.GET)
public String overview(HttpServletRequest request, Model model) {
    Attrs attrs = getAttrs(request);
    UserLocale.initUser(getUser(request));
    User user = UserLocale.getUser();
    List<FactoryMaster> factoryList = getFactoryList(attrs);
    List<CountryMaster> countryList = getCountryList(attrs);
    Command command = initCommand(attrs);
    model.addAttribute(command);
    if(user.hasRole(User.NORMAL)&& user.getCountryCode() != null){
        if(countries == null){
             countries=  getDaoBuilder().getDaoCountry().countryMap();               
         }
        String isoCode = countries.get(user
                .getCountryCode());
        List<CountryMaster> buffer = new ArrayList<CountryMaster>();
        for(CountryMaster i : countryList){
            if(isoCode.equalsIgnoreCase(i.getIsoCode())){
                buffer.add(i);                  
            }
        }
        System.out.println("List size: "+buffer.size());
        command.setCountries(buffer);       
    }
    else{
        command.getCountries().addAll(getCountryList(attrs));
    }
    command.getModels().addAll(getModelList(attrs));
    command.setBrands(getBrandList(attrs));
    return "/reporting/overview";
}
private List<CountryMaster> getCountryList(Attrs attrs) {
    List<CountryMaster> result = new ArrayList<CountryMaster>();
    CountryMaster ct = new CountryMaster(CountryMaster.ISO_COUNTRY_JOKER, 00);
    ct.setDescription("ALL");
    result.add(ct);
    result.addAll(attrs.countryList);
    return result;
}

在HTML页面上，我可以在其他列表中看到第一个元素具有属性selected="selected"。有人知道为什么当我操纵我的列表时，情况不是这样吗?或者有人知道什么是负责这个选择属性分配?(这是javascript, java属性，…?)

提前感谢!

Answer 1

原来列表框的值是可以设置的:这段代码使得它很容易修复:

public String overview(HttpServletRequest request, Model model) {
Attrs attrs = getAttrs(request);
UserLocale.initUser(getUser(request));
User user = UserLocale.getUser();
List<FactoryMaster> factoryList = getFactoryList(attrs);
List<CountryMaster> countryList = getCountryList(attrs);
Command command = initCommand(attrs);
model.addAttribute(command);
if(user.hasRole(User.NORMAL)&& user.getCountryCode() != null){
    if(countries == null){
         countries=  getDaoBuilder().getDaoCountry().countryMap();               
     }
    String isoCode = countries.get(user
            .getCountryCode());
    List<CountryMaster> buffer = new ArrayList<CountryMaster>();
    for(CountryMaster i : countryList){
        if(isoCode.equalsIgnoreCase(i.getIsoCode())){
            buffer.add(i);                  
        }
    }
    System.out.println("List size: "+buffer.size());
    command.setCountries(buffer); 
    // FIXED SELECTION OF ELEMENT
    command.setFactoryValues(new String[]{isoCode});
    // FIXED SELECTION OF ELEMENT   
}
else{
    command.getCountries().addAll(getCountryList(attrs));
}
    command.getModels().addAll(getModelList(attrs));
    command.setBrands(getBrandList(attrs));
    return "/reporting/overview";
}

通过这种方式，您可以使用代码设置列表框的值，并且当页面打开时-该值已经存在，使其成为默认选择