Spring MVC – JSTL forEach Tag with Example

JSP Standard Tag Library (JSTL) is a set of tags that can be used for implementing some common operations such as looping, conditional formatting, and others. JSTL aims to provide an easy way to maintain SP pages The use of tags defined in JSTL has Simplified the task of the designers to create Web pages. They can now simply use a tag related to the task that they need to implement on a JSP page.

To read more in-depth about JSTL refer to the article: JSP Standard Tag Library

The <c:forEach> tag is a commonly used tag because it iterates over a collection of objects. For example, ${list} points to a List<Object>, then the following

<c:forEach var="item" items="${list}" >
    ${item}
</c:forEach>

does basically the same as following in “core Java”:

for (Object item : list) {
    System.out.println(item);
}

So in this article, we are going to discuss the JSTL forEach Tag in detail with an example project in Spring MVC. 

Example Project

Setup the Project

We are going to use Spring Tool Suite 4 IDE for this project. Please refer to this article to install STS on your local machine How to Download and Install Spring Tool Suite (Spring Tools 4 for Eclipse) IDE? Go to your STS IDE then create a new maven project, File > New > Maven Project, and choose the following archetype as shown in the below image as follows:  

Add the following maven dependencies and plugin to your pom.xml file. 

<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.3.18</version>
</dependency>

<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>4.0.1</version>
    <scope>provided</scope>
</dependency>

<!-- plugin -->
<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>2.6</version>
            <configuration>
                <failOnMissingWebXml>false</failOnMissingWebXml>
            </configuration>
        </plugin>
    </plugins>
</build>

Below is the complete code for the pom.xml file after adding these dependencies.

File: pom.xml 

XML

<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.geeksforgeeks</groupId>
    <artifactId>simple-calculator</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>simple-calculator Maven Webapp</name>
    <url>http://maven.apache.org</url>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.18</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <finalName>simple-calculator</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.6</version>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Configuring Dispatcher Servlet

Before moving into the coding part let’s have a look at the file structure in the below image. 

Note: Please refer to the green color box files. Other files are not present in this project. 

So at first create an src/main/java folder and inside this folder create a class named CalculatorAppIntilizer and put it inside the com.geeksforgeeks.calculator.config package and extends the AbstractAnnotationConfigDispatcherServletInitializer class. Refer to the below image.

And whenever you are extending this class, it has some pre abstract methods that we need to provide the implementation. Now inside this class, we have to just write two lines of code to Configure the Dispatcher Servlet. Before that, we have to create another class for the Spring configuration file. So, go to the src/main/java folder and inside this folder create a class named CalculatorAppConfig and put it inside the com.geeksforgeeks.calculator.config package. Below is the code for the CalculatorAppConfig.java file.

File: CalculatorAppConfig.java

Java

package com.geeksforgeeks.calculator.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan(basePackages = "com.geeksforgeeks.calculator.controllers")
public class CalculatorAppConfig {

}

And below is the complete code for the CalculatorAppIntilizer.java file. Comments are added inside the code to understand the code in more detail.

File: CalculatorAppIntilizer.java

Java

package com.geeksforgeeks.calculator.config;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class CalculatorAppIntilizer extends AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    protected Class<?>[] getRootConfigClasses() {
        // TODO Auto-generated method stub
        return null;
    }

    // Registering the Spring config file
    @Override
    protected Class<?>[] getServletConfigClasses() {
        Class aClass[] = { CalculatorAppConfig.class };
        return aClass;
    }

    // Add mapping url
    @Override
    protected String[] getServletMappings() {
        String arr[] = { "/geeksforgeeks.org/*" };
        return arr;
    }

}

Setup ViewResolver

Spring MVC is a Web MVC Framework for building web applications. In generic all MVC frameworks provide a way of working with views. Spring does that via the ViewResolvers, which enables you to render models in the browser without tying the implementation to specific view technology. Refer to the following article ViewResolver in Spring MVC. So for setting up ViewResolver go to the CalculatorAppConfig.java file and write down the code as follows

@Bean
public InternalResourceViewResolver viewResolver() {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/view/");
        viewResolver.setSuffix(".jsp");
        return viewResolver;
    }

And below is the updated code for the CalculatorAppConfig.java file after writing the code for setting up the ViewResolver. 

File: Updated CalculatorAppConfig.java

Java

package com.geeksforgeeks.calculator.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@EnableWebMvc
@Configuration
@ComponentScan(basePackages = "com.geeksforgeeks.calculator.controllers")
public class CalculatorAppConfig {

    // setup ViewResolver
    @Bean
    public InternalResourceViewResolver viewResolver() {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/view/");
        viewResolver.setSuffix(".jsp");
        return viewResolver;
    }

}

Create Controller 

Go to the src/main/java folder and inside this folder create a class named Jstldemocontroller and put it inside the com.geeksforgeeks.calculator.controllers package. Below is the code for the Jstldemocontroller.java file. In this file, we are going to create the ArrayList. 

File: Jstldemocontroller.java file

Java

package com.geeksforgeeks.calculator.controllers;

import java.util.ArrayList;
import java.util.List;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class Jstldemocontroller {

    @RequestMapping("/jstldemo")
    public ModelAndView showHomePage() {

        // Create the List of Skills
        List<String> skills = new ArrayList<String>();
        skills.add("Data Sceince");
        skills.add("Data Structure");
        skills.add("Javascript");
        skills.add("Python");
        skills.add("SQL");

        // Using ModelAndView
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.setViewName("jstl-demo-page");
        modelAndView.addObject("skillList", skills);

        return modelAndView;

    }

}

Create JSP Page and Iterate List using JSTL

Now we have to create a view named “registration-page” inside the WEB-INF/view folder with the .jsp extension. So go to the src > main > webapp > WEB-INF and create a folder view and inside that folder create a jsp file named jstl-demo-page. Before using JSTL we have to make the following changes to our project. 

Step 1: Add the below dependency to your pom.xml file. 

XML

<!-- https://mvnrepository.com/artifact/jstl/jstl -->
<dependency>
    <groupId>jstl</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
</dependency>

Step 2: Add the JSTL tags in the JSP files (Here  jstl-demo-page.jsp file).

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

Step 3: Write down the following for loop to iterate the Array.

<c:forEach var="skill" items="${skillList}">
            <li>${skill}</li>
</c:forEach>

Below is the complete code for the jstl-demo-page.jsp file. 

File: jstl-demo-page.jsp

HTML

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<html>
<head>
</head>
<body>
    <h3>List Without Iteration :</h3>
    ${skillList}
    <h3>List With Iteration :</h3>
    <ul>

        <c:forEach var="skill" items="${skillList}">
            <li>${skill}</li>
        </c:forEach>

    </ul>
</body>
</html>

So now we have done with the coding part. Let’s run and test our application. 

Run Your Application

To run our Spring MVC Application right-click on your project > Run As > Run on Server. And run your application as shown in the below image as depicted below as follows:  

After that use the following URL to run your controller

http://localhost:8080/simple-calculator/geeksforgeeks.org/jstldemo

Output:

So on the output screen, you can see both the list with and without Iteration.