Spring FreeMarker

last modified October 18, 2023

Spring FreeMarker tutorial shows how to use FreeMarker template engine in a classic Spring application.

Spring is a popular Java application framework for creating enterprise applications.

FreeMarker

FreeMarker is a server-side Java template engine for both web and standalone environments. Templates are written in the FreeMarker Template Language (FTL), which is a simple, specialized language. FreeMarker templates have .ftlh extension.

Spring FreeMarker example

The following application uses FreeMarker to generate views.

pom.xml src ├───main │ ├───java │ │ └───com │ │ └───zetcode │ │ ├───config │ │ │ MyWebInitializer.java │ │ │ WebConfig.java │ │ ├───controller │ │ │ MyController.java │ │ └───service │ │ WordService.java │ └───resources │ │ logback.xml │ └───templates │ index.ftlh │ showWords.ftlh └───test └───java

This is the project structure.

pom.xml

<?xml version=“1.0” encoding=“UTF-8”?> <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/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion>

<groupId>com.zetcode</groupId>
<artifactId>springfreemarkerex</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>17</maven.compiler.source>
    <maven.compiler.target>17</maven.compiler.target>
    <spring-version>5.3.23</spring-version>
</properties>

<dependencies>

    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.4.0</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${spring-version}</version>
    </dependency>

    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
        <scope>provided</scope>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context-support</artifactId>
        <version>${spring-version}</version>
    </dependency>

    <dependency>
        <groupId>org.freemarker</groupId>
        <artifactId>freemarker</artifactId>
        <version>2.3.31</version>
    </dependency>

</dependencies>

<build>
    <plugins>

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>3.3.2</version>
        </plugin>

        <plugin>
            <groupId>org.eclipse.jetty</groupId>
            <artifactId>jetty-maven-plugin</artifactId>
            <version>9.4.49.v20220914</version>
        </plugin>
    </plugins>
</build>

</project>

In the pom.xml we have the necessary dependencies.

resources/logback.xml

<?xml version=“1.0” encoding=“UTF-8”?> <configuration> <logger name=“org.springframework” level=“ERROR”/> <logger name=“com.zetcode” level=“INFO”/>

<appender name="consoleAppender" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
        <Pattern>%d{HH:mm:ss.SSS} %blue(%-5level) %magenta(%logger{36}) - %msg %n
        </Pattern>
    </encoder>
</appender>

<root>
    <level value="INFO" />
    <appender-ref ref="consoleAppender" />
</root>

</configuration>

The logback.xml is a configuration file for the Logback logging library.

com/zetcode/config/MyWebInitializer.java

package com.zetcode.config;

import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

@Configuration public class MyWebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

@Override
protected Class<?>[] getRootConfigClasses() {
    return null;
}

@Override
protected Class<?>[] getServletConfigClasses() {

    return new Class[]{WebConfig.class};
}

@Override
protected String[] getServletMappings() {

    return new String[]{"/"};
}

}

MyWebInitializer registers the Spring DispatcherServlet, which is a front controller for a Spring web application.

@Override protected Class<?>[] getServletConfigClasses() {

return new Class[]{WebConfig.class};

}

The getServletConfigClasses returns a web configuration class.

com/zetcode/config/WebConfig.java

package com.zetcode.config;

import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.config.annotation.EnableWebMvc; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer; import org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer; import org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver;

@Configuration @EnableWebMvc @ComponentScan(basePackages = {“com.zetcode”}) public class WebConfig implements WebMvcConfigurer {

@Bean
public FreeMarkerViewResolver freemarkerViewResolver() {

    var resolver = new FreeMarkerViewResolver();
    resolver.setCache(true);
    resolver.setSuffix(".ftlh");
    return resolver;
}

@Bean
public FreeMarkerConfigurer freemarkerConfig() {

    var freeMarkerConfigurer = new FreeMarkerConfigurer();
    freeMarkerConfigurer.setTemplateLoaderPath("classpath:/templates/");
    return freeMarkerConfigurer;
}

}

WebConfig configures FreeMarker template engine. We set the template files location to templates directory on the classpath. (The resources is on the classpath.)

com/zetcode/service/WordService.java

package com.zetcode.service;

import org.springframework.stereotype.Service; import java.util.List;

@Service public class WordService {

private final List<String> words = List.of("pen", "sky",
        "rock", "forest", "falcon", "eagle");

public List<String> all() {

    return words;
}

}

The WordService returns a few words.

com/zetcode/controller/MyController.java

package com.zetcode.controller;

import com.zetcode.service.WordService; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.GetMapping;

@Controller public class MyController {

@GetMapping(value = "/")
public String home() {

    return "index";
}

@GetMapping(value = "/words")
public String showWords(Model model, WordService wordService) {

    var words = wordService.all();
    model.addAttribute("words", words);

    return "showWords";
}

}

MyController provides mappings between request paths and handler methods. We have two mappings: the home page and the showWords page.

var words = wordService.all(); model.addAttribute(“words”, words);

We retrieve all the words using the wordService and put it into the model. The model is passed to FreeMarker which will process the data in the template.

resources/templates/index.ftlh

<!DOCTYPE html> <html lang=“en”> <head> <meta charset=“UTF-8”> <title>Home page</title> </head> <body>

<p> <a href=“words”>Show words</a> </p>

</body> </html>

The home page contains the anchor which shows all words.

resources/templates/showWords.ftlh

<!DOCTYPE html> <html lang=“en”> <head> <meta charset=“UTF-8”> <title>Show words</title> </head> <body>

<h2>List of words</h2>

<ul> <#list words as word> <li>${word}</li> </#list> </ul>

</body> </html>

With the FreeMarker’s list directive, we show all the words in an HTML list.

$ mvn jetty:run

We run the server and locate to localhost:8080 to get the home page, which has the anchor.

In this article we have worked with the FreeMarker template engine in a classic Spring application.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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