Professional Java for Web Applications

Chapter 6Using the Expression Language in JSPs

IN THIS CHAPTER

• All about Expression Language
• How to write with the EL syntax
• How to use scoped variables in EL expressions
• How to access collections with Java 8 streams in EL expressions
• Switching out Java code with Expression Language

WROX.COM CODE DOWNLOADS FOR THIS CHAPTER

You can find the wrox.com code downloads for this chapter at www.wrox.com/go/projavaforwebapps on the Download Code tab. The code for this chapter is divided into the following major examples:

• User-Profile Project
• Customer-Support-v4 Project

NEW MAVEN DEPENDENCIES FOR THIS CHAPTER

In addition to Maven dependencies introduced in previous chapters, you also need the following Maven dependency:

        <dependency>
            <groupId>javax.el</groupId>
            <artifactId>javax.el-api</artifactId>
            <version>3.0.0</version>
            <scope>provided</scope>
        </dependency>

UNDERSTANDING EXPRESSION LANGUAGE

Up to this point, you have used Java to output dynamic content from your JSPs. However, recall that Chapter 4 covers how the use of declarations, scriptlets, and expressions is discouraged. Not only does this provide a great deal of power (sometimes too much) to your JSPs, but it also makes writing JSPs difficult for UI developers with little or no Java background. There must be an easier way to display data and perform simple operations than using Java code. You might think that the <jsp> tags could provide a solution, and indeed these tags can be used to replace certain Java operations. ...