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Last edited time
Jun 25, 2024 11:28 AM
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👉 Overview
👀 What ?
The Expression Language (EL) is a scripting language that can be used in JSP to simplify the accessibility of data stored in the Java Bean component. It provides an easier way to manipulate and access application data on JSP pages.
🧐 Why ?
EL is important because it resolves the complexities of accessing data in JSP. Traditionally, developers had to write extensive Java code in JSP to access the bean components. With EL, accessing data becomes more straightforward and it reduces the amount of Java code needed in JSP. This makes the code cleaner and easier to maintain.
⛏️ How ?
To use EL in a JSP page, the syntax is ${expression}. Here, expression is the data we are trying to access. For example, to access a bean named 'user' and get the value of its 'name' property, we use ${user.name}. This directly returns the name of the user from the bean without writing any explicit Java code.
⏳ When ?
EL was introduced in JSP 2.0. It has since become a staple in web development with Java and JSP.
⚙️ Technical Explanations
EL works by evaluating the expressions in the ${} syntax. It then looks for the named bean in various scopes like page, request, session, and application. If it finds the bean, it tries to access the property mentioned in the expression. If the property is found, it returns the value. If not, it returns null. EL also supports array and collection objects. It can access the data in these objects using the '.' or '[]' operator. For example, ${arrayObj[1]} or ${listObj[0]}.