我如何处理 JS 从复选框中获取的值，然后在 Java 操作中对其进行处理？

Question

I have a checkbox like this in JSP

<input type="checkbox" id="checkBox" name="checkBox"/>

In JS file I wrote a function to set data for a variable when checkbox be clicked

$("checkBox").change(function(){
var checkBox= 0;
if(this.checked) {
    checkBox= 1;
} else {
    checkBox= 0;
}
})

Then in Java action class I want to do something when checkbox be clicked

if(bean.getCheckBox == 1) {//do something}

But it's not working. Please help me fix this one ! thanks

Answer 1

The var checkBox is a client-side JavaScript local variable and its value will only ever be visible inside the change event listener; your action class which (I'm assuming) is a server side component will not have access to this value.

Your action class should instead check for the value of the checkBox request parameter which comes from the value attribute.

<input type="checkbox" id="checkBox" name="checkBox" value="1" />

Then in your action class you'll have something like:

if ("1".equals(request.getParameter("checkBox"))) {
    ...
}

Or, you can also simply do a null-check and not check for any specific value.

if (request.getParameter("checkBox") != null) {
    ...
}

If you're using some framework bean, you'll use something like below depending on the bean's checkBox variable's data type.

if ("1".equals(bean.getCheckBox())) { // String
    ...
}

// or
if (bean.getCheckBox() != null) { // String or Integer
    ...
}

// or
if (bean.getCheckBox() == 1) { // int primitive
    ...
}

The value to check for still comes from the value attribute above.