spring中formAttribute和commandName属性在form标签中的区别？ [英] Difference between modelAttribute and commandName atributes in form tag in spring?

问题描述

我是Spring 3的新手，所以可能我正在问一个糟糕的标准问题。我在jsp中看到了两个不同的form标签属性：

 < form：form method =postmodelAttribute =login > 
  

在此属性中，modelAttribute是表单对象的名称，其属性用于填充表单。我用它发布表单并在控制器中使用 @ModelAttribute 来捕获值，调用验证器，应用业务逻辑。这里一切都很好。现在

 < form：form method =postcommandName =login> 
  

这个属性期望什么，它也是一个表单对象，它的属性我们将要填充？ ？

解决方案

如果您查看源代码 FormTag （4.3.x），它支持你的< form> 元素，你会注意到这个

  / ** 
 *在模型中设置表单属性的名称。 
 *< p>可能是一个运行时表达式。 
 * / 
 public void setModelAttribute（String modelAttribute）{
 this.modelAttribute = modelAttribute; 
} 
 
 / ** 
 *获取模型中表单属性的名称。 
 * / 
保护字符串getModelAttribute（）{
返回this.modelAttribute; 
} 
 
 / ** 
 *在模型中设置表单属性的名称。 
 *< p>可能是一个运行时表达式。 
 * @see #setModelAttribute 
 * / 
 public void setCommandName（String commandName）{
 this.modelAttribute = commandName; 
} 
 
 / ** 
 *获取模型中表单属性的名称。 
 * @see #getModelAttribute 
 * / 
 protected String getCommandName（）{
 return this.modelAttribute; 
} 
  

它们都指向相同的字段，因此具有相同的效果。 p>

但是，正如字段名称所示， modelAttribute 应该是首选的，正如其他人也指出的那样。

I am new to Spring 3 so may be I am asking a poor standard question. I have seen two different attribute in form tag in jsp

<form:form method="post" modelAttribute="login">

in this the attribute modelAttribute is the name of the form object whose properties are used to populate the form. And I used it in posting a form and in controller I have used @ModelAttribute to capture value, calling validator, applying business logic. Everything is fine here. Now

<form:form method="post" commandName="login">

What is expected by this attribute, is it also a form object whose properties we are going to populate??

解决方案

If you look at the source code of FormTag (4.3.x) which backs your <form> element, you'll notice this

/**
 * Set the name of the form attribute in the model.
 * <p>May be a runtime expression.
 */
public void setModelAttribute(String modelAttribute) {
    this.modelAttribute = modelAttribute;
}

/**
 * Get the name of the form attribute in the model.
 */
protected String getModelAttribute() {
    return this.modelAttribute;
}

/**
 * Set the name of the form attribute in the model.
 * <p>May be a runtime expression.
 * @see #setModelAttribute
 */
public void setCommandName(String commandName) {
    this.modelAttribute = commandName;
}

/**
 * Get the name of the form attribute in the model.
 * @see #getModelAttribute
 */
protected String getCommandName() {
    return this.modelAttribute;
}

They are both referring to the same field, thus having same effect.

But, as the field name indicates, modelAttribute should be preferred, as others have also pointed out.

这篇关于spring中formAttribute和commandName属性在form标签中的区别？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IT屋！