Preliminary use of El expressions

I'm a rookie , If there is something wrong in the article , Or the expression is not clear , Please remind me in the comments .java I only studied for a few months , More commonly used jsp, So the content logic of the article is based on jsp Written in actual combat .

In my submission el Expressions are mainly used on pages , With it, the page can be used directly for Circulation and if sentence , Get rid of JavaScript, Save some code , Work well .

First of all el The scope of the expression pageContext. Use it to extract in servlet Save in session Data in ,session Has a long life cycle , Refresh will not reset session Of the data in , So use session To store login ID Or other data , It's more convenient to use .

El Of expression cfoEachr Loops can support and iterate Array of basic data prototype 、 Strings separated by commas 、List aggregate 、SQL Query the row obtained 、Object Instance array   wait . How to use cforEach：

Put the set or array that needs iteration in items Element ,var The element represents the data of each index in the iterated data . stay cforEach In the place html label , Insert data into the label , By iteration , There can be several indexes , There are just a few option label .

cif Use of judgment ：

Go to test Liser's judgment statement is true Is executed , by false Just skip. .

stay ${ } In braces of , You can also create variables , Then use variables to record values , Then through these statements forEach、if Reference variables , To accomplish some goals