El Expression-3

2. Implied objects related to the input

There are two hidden objects associated with the input:param and paramvalues, which are the more specific hidden objects in El.

For example, when we want to get the user's request parameters, we can take advantage of the following methods:

Request.getparameter (string name)
 request.getparametervalues (string name)

In El, you can use both Param and paramvalues to get the data.

${param.name}

${paramvalues.name}

3. Other hidden Objects

Cookies

JSTL does not provide a cookie-setting action,

Example: To get a value in a cookie that has a setting name of Usercountry, you can use ${cookie.usercountry} to get it.

headers and headervalues

The header stores the data that the user's browser and server use to communicate

Example: To get the version of the user's browser, you can use ${header["User-agent"}.

In some cases, it is possible to have different values for the same header name, and you must instead use Headervalues to obtain these values.

Initparam

Initparam get environment parameters for setting Web site (context)

Example: General method string Userid= (String) application.getinitparameter ("userid");

You can use ${initparam.userid} to get the name UserID