Question

为什么spring没有绑定嵌套对象上的值？

RegistrationBean上的SecurityQuestion对象分别设置为问题和答案为null，null，尽管在视图中使用bean表示法在表单中进行设置。

豆类：

public class SecurityQuestion {
  SecurityQuestionType type;
  String answer;
}

public class RegistrationBean {
  @Valid
  SecurityQuestion securityQuestion;
  String name;


  public SecurityQuestionType[] getSecurityQuestionOptions() {
    return SecurityQuestionType.values();
  }
}

查看：

<form:form modelAttribute="registrationBean" method="POST">
  <form:select id="securityQuestion" path="securityQuestion.question">
    <c:forEach var="securityQuestionOption" items="${securityQuestionOptions}">
      <form:option value="${securityQuestionOption}">${securityQuestionOption</form:option>
    </c:forEach>
  </form:select>

  <form:input id="securityAnswer" path="securityQuestion.answer" />
  <form:input id="name" path="name" />
</form:form>

控制器：

@RequestMapping(value = URL_PATTERN, method = RequestMethod.POST)
public ModelAndView submit(@Valid final RegistrationBean registrationBean) {
  // registrationBean.getSecurityQuestion().getQuestion() == null
  // registrationBean.getSecurityQuestion().getAnswer() == null
}

解决方案

所有bean都必须拥有所有字段的getter / setter。 Spring使用默认构造函数，然后使用setter从视图中改变对象。

Answer 1

您可以尝试为RegistrationBean提供合适的getter / setter。

public class RegistrationBean {
  @Valid
  SecurityQuestion securityQuestion;
  String name;

  public SecurityQuestion getSecurityQuestion(){
        return securityQuestion;
  }
  public void setSecurityQuestion(SecurityQuestion q){
      this.securityQuestion = q;
  }    
  public SecurityQuestionType[] getSecurityQuestionOptions() {
    return SecurityQuestionType.values();
  }
}

Spring 3.0 MVC绑定嵌套对象

1 个答案: