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Freemarker TemplateLoader with MultiTemplateLoader Example

By Arvind Rai, October 18, 2015
On this page we will provide Freemarker TemplateLoader with MultiTemplateLoader example. freemarker.cache.MultiTemplateLoader is the collection of other TemplateLoader class instances. These TemplateLoader classes are ClassTemplateLoader, StringTemplateLoader, FileTemplateLoader etc. In our example we are using ClassTemplateLoader and StringTemplateLoader. We will instantiate these loaders and will put in array of TemplateLoader using which MultiTemplateLoader will be instantiated. Now using getTemplate() method of Configuration class, we will be able to access all templates loaded by ClassTemplateLoader and StringTemplateLoader as usual. Find the complete example.

build.gradle

Find the gradle file to resolve Freemarker JAR dependency.
apply plugin: 'java'
apply plugin: 'eclipse'
archivesBaseName = 'Concretepage'
version = '1.0-SNAPSHOT' 
repositories {
    maven { url "https://repo.spring.io/libs-release" }
    mavenLocal()
    mavenCentral()
}
dependencies {
    compile 'org.freemarker:freemarker:2.3.23'
} 



Template for ClassTemplateLoader

Find the template for ClassTemplateLoader.
template1.ftl
College : ${college}
Location : ${location}  

Freemarker Configuration with TemplateLoader and MultiTemplateLoader

We are using ClassTemplateLoader and StringTemplateLoader which will be added in MultiTemplateLoader in our demo.
ConfigurationUtil.java
package com.concretepage.freemarker;
import freemarker.cache.ClassTemplateLoader;
import freemarker.cache.MultiTemplateLoader;
import freemarker.cache.StringTemplateLoader;
import freemarker.cache.TemplateLoader;
import freemarker.template.Configuration;
import freemarker.template.TemplateExceptionHandler;
public class ConfigurationUtil {
    private static Configuration configuration ;
    static {
        configuration = new Configuration(Configuration.VERSION_2_3_23);
        //First loader
        ClassTemplateLoader classLoader = new ClassTemplateLoader(
        		new ConfigurationUtil().getClass(), "/ftl");
        //Second loader
        StringTemplateLoader stringLoader = new StringTemplateLoader();
        stringLoader.putTemplate("template2.ftl", "Hello! My name is ${name} and I am from ${country}");
        // Create TemplateLoader array 
        TemplateLoader[] loaderArray = {classLoader, stringLoader};
        //Instantiate MultiTemplateLoader
        MultiTemplateLoader loader = new MultiTemplateLoader(loaderArray);
        //Set to Configuration
        configuration.setTemplateLoader(loader);
        configuration.setDefaultEncoding("UTF-8");
        configuration.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);
    }
    public static Configuration getConfiguration() {
       return configuration;
    }
} 

Main Class


MultiTemplateLoaderDemo.java
package com.concretepage.freemarker;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;
import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateException;
public class MultiTemplateLoaderDemo {
	public static void main(String[] args) {
         try {
            Configuration cfg = ConfigurationUtil.getConfiguration();
            //Create Data Model for first template 
            Map map1 = new HashMap<>();
            map1.put("college", "ABC College");
            map1.put("location", "Varanasi");
            Template template1 = cfg.getTemplate("template1.ftl");
            //Create Data Model for second template             
            Map map2 = new HashMap<>();
            map2.put("name", "Ram Chandra");
            map2.put("country", "India");
            Template template2 = cfg.getTemplate("template2.ftl");
            
            Writer console = new OutputStreamWriter(System.out);
            //Console output for first template
            System.out.println("--Console output for first template--");
            template1.process(map1, console);
            console.flush();
            //Console output for second template
            System.out.println("\n--Console output for second template--");
            template2.process(map2, console);
            console.flush();
            //File output
            Writer file1 = new FileWriter (new File("template-output1.txt"));
            template1.process(map1, file1);
            file1.flush();
            file1.close();
            Writer file2 = new FileWriter (new File("template-output2.txt"));
            template2.process(map2, file2);
            file2.flush();
            file2.close();
         } catch (IOException e) {
            e.printStackTrace();
         } catch (TemplateException e) {
            e.printStackTrace();
         }
 	}
} 
Find the output.
--Console output for first template--
College : ABC College
Location : Varanasi 
--Console output for second template--
Hello! My name is Ram Chandra and I am from India  

Download Source Code

POSTED BY
ARVIND RAI
ARVIND RAI
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