FreeMarker: String concatenation

Using ‘+’ operator, you can concatenate strings.

 

Example

<#assign str1="Foo" >

<#assign str2="Bar" >

<#assign str3="Fin" >

 

<#assign result = str1 + "," + str2 + "," + str3>

 

Find the below working application.

 

Step 1: Define stringConctenation.ftl file under src/main/resources/templates folder.

 

stringConctenation.ftl

<#assign str1="Foo" >
<#assign str2="Bar" >
<#assign str3="Fin" >

<#assign result = str1 + "," + str2 + "," + str3>

Value Of str1 is : ${str1}
Value Of str2 is : ${str2}
Value Of str3 is : ${str3}
Value Of result is : ${result}

Step 2: Define ‘FreeMarkerUtil’ class that takes model object and template file as input and merge them.

 

FreeMarkerUtil.java

package com.sample.app.util;

import java.io.StringWriter;
import java.util.Locale;

import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateExceptionHandler;

public class FreeMarkerUtil {

	private static final Configuration FREE_MARKER_CONFIGURATION = new Configuration(Configuration.VERSION_2_3_30);

	static {
		FREE_MARKER_CONFIGURATION.setClassForTemplateLoading(FreeMarkerUtil.class, "/templates/");
		FREE_MARKER_CONFIGURATION.setDefaultEncoding("UTF-8");
		FREE_MARKER_CONFIGURATION.setLocale(Locale.US);
		FREE_MARKER_CONFIGURATION.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);
		FREE_MARKER_CONFIGURATION.setFallbackOnNullLoopVariable(false);
	}

	public static StringWriter mergeModelAndTemplate(Object modelObject, String ftlFile) throws Exception {
		StringWriter stringWriter = new StringWriter();

		Template template = FREE_MARKER_CONFIGURATION.getTemplate(ftlFile);

		template.process(modelObject, stringWriter);

		return stringWriter;
	}

}

Step 3: Define StringConcatenationPopulator.

 

StringConcatenationPopulator.java

package com.sample.app;

import java.io.StringWriter;
import java.util.HashMap;
import java.util.Map;

import com.sample.app.util.FreeMarkerUtil;

public class StringConcatenationPopulator {
	public static void main(String args[]) throws Exception {

		Map<String, Object> modelObject = new HashMap<String, Object>();
		
		StringWriter stringWriter = FreeMarkerUtil.mergeModelAndTemplate(modelObject, "stringConcatenation.ftl");
		System.out.println(stringWriter.toString().trim());

	}
}

Output

Value Of str1 is : Foo
Value Of str2 is : Bar
Value Of str3 is : Fin
Value Of result is : Foo,Bar,Fin

Previous                                                    Next                                                    Home