[英]Display JSR-303 errors before form submission with Spring MVC
在提交表單之前,Spring MVC 3.x中是否有一種簡單的方法來顯示表單錯誤消息(通過JSR303驗證獲得)?
請考慮本文結尾處的示例代碼。
最終用戶應該編輯其中初始數據已經無效的表單。
提交表單時,錯誤會正確顯示(POST方法),但在初始表單顯示時(GET方法)不會正確顯示錯誤。
有沒有一種簡單的方法可以在初始表單顯示中顯示錯誤(GET方法)? (是否有一種方法可以為此目的重新使用form:errors標簽?)
JSP查看 form1.jsp:
<%@ page session="true" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://www.springframework.org/tags" prefix="s" %>
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form" %>
<html><body>
<form:form commandName="form1" method="post">
<s:bind path="*">
<c:if test="${status.error}">
<div style="color: red;">There are errors:</div>
<form:errors /><br />
</c:if>
</s:bind>
<form:label path="field1" >Field1:</form:label>
<form:input path="field1" />
<form:errors path="field1" cssStyle="color: red;"/>
<br />
<form:label path="field2" >Field2:</form:label>
<form:input path="field2" />
<form:errors path="field2" cssStyle="color: red;"/>
<br />
<form:button name="submit">Ok</form:button>
</form:form>
</body></html>
控制器 :
@Controller @SessionAttributes("form1")
public class Form1Controller {
@ModelAttribute("form1") public Form1Bean createForm1() { return new Form1Bean(); }
@RequestMapping(value = "/form1/edit", method = RequestMethod.GET)
public String getEdit(Model model) {
// here we pretend to get form1 from database, and store it in session.
// form1 in database may have invalid field values.
// Perform a JSR-303 validation here ?
// MAIN QUESTION: What's the easy way to add errors to model and display them ?
return "/form1";
}
@RequestMapping(value = "/form1/edit", method = RequestMethod.POST)
public String postEdit(@Valid @ModelAttribute("form1") Form1Bean form1, BindingResult result, Model model) {
if (result.hasErrors()) {
return "/form1";
} else {
return "redirect:/done";
}
}
}
菜豆 :
public class Form1Bean {
@Size(min=4,max=10) private String field1; // getters and setters ommited for brevity
@Size(min=4,max=10) private String field2;
public Form1Bean() {
this.field1 = "bad"; this.field2="good"; // start with an invalid field1
}
//...
}
編輯:從@ jb-nizet解釋答案后,這里是完整的控制器源 :
@Controller @SessionAttributes("form1")
public class Form1Controller {
@Autowired org.springframework.validation.Validator validator;
@ModelAttribute("form1") public Form1Bean createForm1() { return new Form1Bean(); }
@RequestMapping(value = "/form1/edit", method = RequestMethod.GET)
public String getEdit(@ModelAttribute("form1") Form1Bean form1, Errors errors, Model model) {
// here we pretend to get form1 from database, and store it in session.
// form1 in database may have invalid field values.
validator.validate(form1, errors);
return "/form1";
}
@RequestMapping(value = "/form1/edit", method = RequestMethod.POST)
public String postEdit(@Valid @ModelAttribute("form1") Form1Bean form1, BindingResult result, Model model) {
if (result.hasErrors()) {
return "/form1";
} else {
return "redirect:/done";
}
}
}
進行了一些測試,似乎可以正常工作! 比你@ jb-nizet
沒有經過測試,但是據我了解的文檔 ,您只需要在控制器中注入org.springframework.validation.Validator
類型的對象,創建並綁定Errors實例即可,如GET METHOD中的“ 添加錯誤”中所述。調用驗證器的validate()方法,並將表單和Errors作為參數傳遞。
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