Expression Language, expressionlanguage

Expression Language, expressionlanguage

If EL cannot find the attribute, "" is returned.

Page -- request --- session --- application

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Get the java object type through EL

$ {Pagination. person. name }== pageContext. getAttribute ("person"). getName ();

$ {Pagination. person. age}

 

 

EL operation List

$ {Pagination. list [1]}: 2nd Elements

 

EL operation Map

$ {Pagination. map. key}

$ {Pagination. map ["key"]}

 

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EL function library

Custom:

1. Write java classes and provide static methods

2. Write a tld file and define the function description in the tld file.

 

Official EL function library in JSTL

Import jstl. jar

Introduce the library namespace in the jsp page

Http://java.sun.com/jsp/jstl/funcionts prefix = "fn"

 

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Jstl is divided into five categories

Core

Fmt Internationalization

SQL database

Xml XML

Fn EL function library

Both database operations and xml operations write the code into the Servlet.

 

Each tag library jar package has/META-INF corresponding to a tld file, called the tag library definition file

Translate the following (Computer Document)

The "executable" attribute can restrict the running of JSF processes only in specific components. The "executable" attribute can point to the ID of the component to be executed. The component can also be identified by Expression Language (EL.
In addition, the "executable" attribute also recognizes the following keywords:

Translate the following (Computer Document)

The "executable" attribute can restrict the running of JSF processes only in specific components. The "executable" attribute can point to the ID of the component to be executed. The component can also be identified by Expression Language (EL.
In addition, the "executable" attribute also recognizes the following keywords: