List to string joining java

2. List to String Using Standard toString() method

List.toString() is the simplest one but it adds the square brackets at the start and end with each string is separated with comma separator.

The drawback is that we can not replace the comma with another separator and can not remove the square brackets.

package com.javaprogramto.convert.list2string; import java.util.Arrays; import java.util.List; /** * Example to convert List to string using toString() method. * * @author javaprogramto.com * */ public class ListToStringUsingToStringExample < public static void main(String[] args) < // creating a list with strings. Listlist = Arrays.asList("One", "Two", "Three", "Four", "Five"); // converting List to String using toString() method String stringFromList = list.toString(); // priting the string System.out.println("String : "+stringFromList); > >

String : [One, Two, Three, Four, Five]

3. List to String Using Java 8 String.join() Method

The above program works before java 8 and after. But, java 8 String is added with a special method String.join() to convert the collection to a string with a given delimiter.

import java.util.Arrays; import java.util.List; /** * Example to convert List to string using String.join() method. * * @author javaprogramto.com * */ public class ListToStringUsingString_JoinExample < public static void main(String[] args) < // creating a list with strings. Listlist = Arrays.asList("One", "Two", "Three", "Four", "Five"); // converting List to String using toString() method String stringFromList = String.join("~", list); // priting the string System.out.println("String with tilde delimiter: "+stringFromList); // delimiting with pipe | symbol. String stringPipe = String.join("|", list); // printing System.out.println("String with pipe delimiter : "+stringPipe); > >

String with tilde delimiter: One~Two~Three~Four~Five String with pipe delimiter : One|Two|Three|Four|Five

4. List to String Using Java 8 Collectors.joining() Method

Collectors.join() method is from java 8 stream api. Collctors.joining() method takes delimiter, prefix and suffix as arguments. This method converts list to string with the given delimiter, prefix and suffix.

Look at the below examples on joining() method with different delimiters. But, String.join() method does not provide the prefix and suffix options.

If you need a custom delimiter, prefix and suffix then go with these. If you do not want the prefix and suffix then provide empty string to not to add any before and after the result string.

import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; /** * Example to convert List to string using Collectors.joining() method. * * @author javaprogramto.com * */ public class ListToStringUsingString_JoinExample < public static void main(String[] args) < // creating a list with strings. Listlist = Arrays.asList("One", "Two", "Three", "Four", "Five"); // using java 8 Collectors.joining with delimiter, prefix and suffix String joiningString = list.stream().collect(Collectors.joining("-", "")); // printing System.out.println("Collectors.joining string : "+joiningString); String joiningString3 = list.stream().collect(Collectors.joining("@", "", "")); // printing System.out.println("Collectors.joining string with @ separator : "+joiningString3); > >

Collectors.joining string : Collectors.joining string with @ separator : One@Two@Three@Four@Five

5. List to String Using Apache Commons StringUtils.join() method

Finally way is using external library from apache commons package. This library has a method StringUtils.join() which takes the list and delimiter similar to the String.join() method.

import org.apache.commons.lang3.StringUtils; /** * Example to convert List to string using apache commons stringutils.join() method. * * @author javaprogramto.com * */ public class ListToStringUsingStringUtils_JoinExample < public static void main(String[] args) < // creating a list with strings. Listlist = Arrays.asList("One", "Two", "Three", "Four", "Five"); // using java 8 Collectors.joining with delimiter, prefix and suffix String joiningString = StringUtils.join(list, "^"); // printing System.out.println("StringUtils.join string with ^ delimiter : "+joiningString); String joiningString3 = StringUtils.join(list, "$"); // printing System.out.println("StringUtils.join string with @ separator : "+joiningString3); > >

StringUtils.join string with ^ delimiter : One^Two^Three^Four^Five StringUtils.join string with @ separator : One$Two$Three$Four$Five

6. Conclusion

In this article, we’ve seen how to convert List to String in java using different methods before and after java 8.

or If you want to add a prefix or suffix then use stream api Collectors.joining() method with delimiter, prefix and suffix values.

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A quick guide to convert List to String in java using different methods and apache commons api with examples.

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Java List to String

We can use StringBuilder class to convert List to String. StringBuilder is the best approach if you have other than String Array, List.We can add elements in the object of StringBuilder using the append() method while looping and then convert it into string using toString() method of String class at the end.

Using + operator

This is not an efficient way so, normally avoid it.We use concate( + ) operator to add one by one element from array inside loop and assign it into String.

Using String’s join method in java 8

String’s join method is introduced in Java 8 . This method is very handy to create delimited separated String from list.

This approach will work only for List of String. In case, if you have list of Double, then you can use java 8‘s Collectors to join the String.
Here is an example:

As you can see, we have used Collectors.joining(«,») to join elements of String by ,

Using Apache common lang3

You can also use Apache common’s StringUtils to convert list to String.
Here is the dependency which you need to add for Apache common lang3 in pom.xml .

Using Guava library

You can also use Guava’s Joiner class to convert list to String.
Here is the dependency which you need to add for guava in pom.xml .

As you can see, we have used com.google.common.base.Joiner class to join elements of String by *

Print elements of list as String

Sometimes, we just need to print elements of the list. We can simply use toString() method
Let’s understand with the help of example.

Did you notice we did not even call toString() method on intList object?
JVM internally calls toString() method of type of element within this list. In this case, we have list of Integers, so it will call Integer’s toString() method.

In case, you have custom object, then you should override toString() method, else it will give you unexpected results.
Let’s see with the help of example
Create a simple class named Color.java

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