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JSP nine large built-in objects
11 objects implied by an EL expression
Implied object name |
Description |
PageContext |
Corresponds to the PageContext object in the JSP page (note: The PageContext object is taken.) ) |
Pagescope |
Represents the Map object in the page field for saving properties |
Requestscope |
Represents the Map object in the Request field for saving properties |
Sessionscope |
Represents the Map object in the Session field for saving properties |
Applicationscope |
Represents the Map object in the Application field for saving properties |
Implied object name |
Description |
Param |
Represents a map object that holds all the request parameters |
Paramvalues |
Represents a map object that holds all the request parameters, and it returns a string[for a request parameter] |
Header |
Represents a map object that holds all the HTTP request header fields |
Headervalues |
Ibid., return string[] array. Note: If there is "-" in the head, example accept-encoding, headervalues["accept-encoding"] |
Cookies |
Represents a map object that holds all cookies |
Initparam |
Represents a map object that holds all the Web application initialization parameters |
Attention:
①: If the value is placed in the domain object can be obtained by ${requestscope.key}, or you can omit requestscope that is ${key}
②: But to get request,session and other objects must use PageContext to obtain, that is ${pagecontext.request.contextpath} and so on
JSP built-in objects and El expression built-in object myths