El Expression-1

EL provides. and [] Two operators to navigate the data. The following two represent the same meaning:

${sessionscope.user.sex}

Equals

${sessionscope.user["Sex"]}

. And [] can also be mixed at the same time, as follows:

${sessionscope.shoppingcart[0].price}

The return result is the price of the first item in ShoppingCart.

However, there are two situations in which the two are different:

(1) When the name of the property to be accessed contains some special characters, such as. or – such as symbols that are not letters or numbers, you must use [], for example: ${user. My-name}

The above is not the correct way, should be replaced by: ${user["My-name"]}

(2) We will consider the following situations:

${sessionscope.user[data]}

At this point, data is a variable, if the value of data is "sex", then the above example equals ${sessionscope.user.sex};

If the value of data is "name", it is equal to ${sessionscope.user.name}. Therefore, if you want to dynamically fetch the value, you can do it with the above method, but. cannot be dynamically evaluated.

El Expression-1