春天的表单标签中的modelAttribute和commandName属性之间的区别? [英] Difference between modelAttribute and commandName attributes in form tag in spring?

问题描述

在Spring 3中，我在jsp的form标记中看到了两个不同的属性

In Spring 3, I have seen two different attribute in form tag in jsp

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

在此属性modelAttribute是表单对象的名称，其属性用于填充表单.在发布表单时使用了它，在控制器中使用了@ModelAttribute来获取值，调用验证器，应用业务逻辑.这里一切都很好.现在

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">

此属性有什么用，它也是我们要填充其属性的表单对象吗?

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

推荐答案

如果您查看

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;
}

它们都指向相同的字段，因此具有相同的效果.

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

但是，正如字段名所示，modelAttribute应该是首选，正如其他人也指出的那样.

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

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