问题描述
首先:我是Spring的初学者,这是我第一次尝试使用Spring MVC实现Web应用程序.这是我已经完成的事情:
First of all: I'm a beginner in Spring and this is my first try to implement an web application with Spring MVC.Here is what I've done yet:
实体:
@Entity
@Table(name = "coins")
public class Coin
{
@Id
@GeneratedValue
private Integer id;
@OneToOne
private Country country;
private double value;
private int year;
}
@Entity
@Table(name = "countries")
public class Country
{
@Id
@GeneratedValue
private Integer id;
private String name;
}
控制器:
@Controller
public class CoinViewController {
@Autowired
private CoinService service;
@Autowired
private CountryService countryService;
@ModelAttribute("countries")
public List<Country> frequencies() {
return countryService.get();
}
@RequestMapping(value = "/coins/add", method = RequestMethod.GET)
public String addCoin(Model model) {
model.addAttribute("coin", new Coin());
return "coins/add";
}
@RequestMapping(value = "/coins/add", method = RequestMethod.POST)
public String addCoinResult(@ModelAttribute("coin") Coin coin, BindingResult result) {
// TODO: POST HANDLING
return "/coins/add";
}
}
JSP:
<form:form action="add" method="POST" modelAttribute="coin">
<div class="form-group">
<label for="country">Country:</label>
<form:select path="country" class="form-control" >
<form:option value="" label="-- Choose one--" />
<form:options items="${countries}" itemValue="id" itemLabel="name" />
</form:select>
</div>
<div class="form-group">
<label for="value">Value:</label>
<form:input path="value" class="form-control" />
</div>
<div class="form-group">
<label for="year">Year:</label>
<form:input path="year" class="form-control" />
</div>
<button type="submit" value="submit" class="btn btn-default">Erstellen</button>
</form:form>
但是,当我尝试保存JSP的输入时,总是会得到以下提示:
But when I try to save the input from the JSP I always get this:
所以我的问题是:
- 我应该使用什么编辑器/转换器?
- 如何在我的控制器中注册其中之一?
推荐答案
您可以将自定义编辑器注册到控制器类的initBinder中:
You can register a custom editor into initBinder of your controller class:
@Controller
public class CoinViewController {
@Autowired
private CountryEditor countryEditor;
@InitBinder
protected void initBinder(final WebDataBinder binder, final Locale locale) {
binder.registerCustomEditor(Country.class, countryEditor);
}
......
}
(在这种情况下不需要locale
参数,但是如果您需要使用语言环境进行转换,例如在使用日期时,该参数很有用)
(locale
parameter is not needed in this case, but it can be useful if you need locale to make conversion - for example if you are working with dates)
,您可以定义您的CountryEditor
,如下所示:
and you can define your CountryEditor
like the following:
@Component
public class CountryEditor extends PropertyEditorSupport {
@Autowired
private CountryService countryService;
@Override
public void setAsText(final String text) throws IllegalArgumentException {
try{
final Country country = countryService.findById(Long.parseLong(text));
setValue(cliente);
}catch(Exception e){
setValue(country);
// or handle your exception
}
}
}
我让spring用@Component
注释处理编辑器的注入.因此,如果您喜欢这种方式,请记住为该类启用程序包扫描!
I let spring handle injection of my editors with @Component
annotation. So if you like to do in that way remember to enable package scan for that class!
希望获得帮助!
这篇关于Spring MVC表单处理的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!