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Thymeleaf is a Java-based template engine used for processing HTML, XML, JS, and many other documents. In this tutorial, we will learn how to iterate over a list of objects in the Thymeleaf HTML page using th:each attribute.

Learn Thymeleaf at https://www.javaguides.net/p/thymeleaf-tutorial.html

In this example, we will create a Spring boot project to demonstrate the iteration in Thymeleaf.

Iteration attribute th:each

Thymeleaf comes with a special attribute th:each, used to iterate over collections of different object types.

There are several objects that Thymeleaf considered iterable:

objects implementing java.util.Iterable interface,
objects implementing java.util.Enumeration interface,
objects implementing java.util.Iterator interface,
objects implementing java.util.Map interface,
and also arrays.

Thymeleaf Loop or Iteration Example with Spring Boot

Let's assume that we want to display a list of employees in a simple HTML table using the Thymeleaf engine.

Maven Dependency

Let's add the below dependency to integrate Thymeleaf with Spring boot:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

Employee Model Class

In our example application Employee object will have the following structure:

package net.javaguides.springboot;

public class Employee {
    private String firstName;
    private String lastName;
    private String email;

    public Employee(String firstName, String lastName, String email) {
        super();
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }

    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
}

Spring MVC Controller - EmployeeController.java

EmployeeController class was defined to handle all GET requests to /iteration URI and return a rendered page iteration.html as an output (which is our Thymeleaf template located in /resources/templates)

package net.javaguides.springboot;

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

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;

@Controller
public class EmployeeController {

    @GetMapping("/iteration")
    public String iteration(Model model) {
        List < Employee > employees = new ArrayList < > ();
        employees.add(new Employee("Ramesh", "Fadatare", "ramesh@gmail.com"));
        employees.add(new Employee("John", "Cena", "john@gmail.com"));
        employees.add(new Employee("Tom", "Cruise", "tom@gmail.com"));
        employees.add(new Employee("Tony", "Stark", "tony@gmail.com"));
        model.addAttribute("employees", employees);
        return "iteration";
    }
}

Thymeleaf template - iteration.html

We will use th:each to iterate through the list of employees:

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">

<head>
    <meta charset="ISO-8859-1">
    <title>Add Bootstrap CSS Demo</title>

    <link th:href="@{/css/bootstrap.min.css}" rel="stylesheet" />
</head>

<body>
    <div class="container">
        <div class="row">
            <h1>Employees</h1>

            <table class="table">
                <thead>
                    <tr>
                        <th>Employee First Name</th>
                        <th>Employee Last Name</th>
                        <th>Employee Email</th>
                    </tr>
                </thead>
                <tbody>
                    <tr th:each="employee : ${employees}">
                        <td th:text="${employee.firstName}"></td>
                        <td th:text="${employee.lastName}"></td>
                        <td th:text="${employee.email}"></td>
                    </tr>
                </tbody>
            </table>
        </div>

    </div>
</body>

</html>

Status Variable

Thymeleaf also enables a useful mechanism to keep track of the iteration process via the status variable.

The status variable provides the following properties:

index: the current iteration index, starting with 0 (zero)
count: the number of elements processed so far
size: the total number of elements in the list
even/odd: checks if the current iteration index is even or odd
first: checks if the current iteration is the first one
last: checks if the current iteration is the last one

Let's see how the status variable works in our example:

<tr th:each="employee : ${employees}"
 th:style="${employeeStat.odd}? 'font-weight: bold;'"
 th:alt-title="${employeeStat.even}? 'even' : 'odd'">
 <td th:text="${employee.firstName}"></td>
 <td th:text="${employee.lastName}"></td>
 <td th:text="${employee.email}"></td>
</tr>

Here, we included the employeeStat.odd property to evaluate the condition and set a bold style for the current row.

The employeeStat is the aggregation of the variable employee with the suffix Stat.

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Thymeleaf Loop or Iteration Example with Spring Boot - th:each Attribute

Iteration attribute th:each

Thymeleaf Loop or Iteration Example with Spring Boot

Maven Dependency

Employee Model Class

Spring MVC Controller - EmployeeController.java

Thymeleaf template - iteration.html

Status Variable

Related Thymeleaf Tutorials and Examples

Related Spring and Spring Boot Tutorials/Guides:

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