Java 8 - StringJoiner with examples

Java 8 - StringJoiner with examples

StringJoiner  

StringJoiner is used to construct a sequence of characters separated by a delimiter and optionally starting with a supplied prefix and ending with a supplied suffix. Internally StringJoiner uses the String.join()

Lets see simple examples with various uses of StringJoiner class.

• Joning string by delimiter
• Other way to join string with delimiter
• List to string
• Adding delimiter, prefix and suffix
• Using setEmptyValue() method
• Using setEmptyValue() method - Same after adding some value
• Merging 2 string joiner 

public class StringJoiners {

 public static void main(String[] args) {
  
  //Joning string by delimiter
  StringJoiner sj = new StringJoiner(",");
  sj.add("Java");
  sj.add("Discover");
  sj.add("2018");
  System.out.println("Joning string by delimiter :: "+ sj.toString());
  
  
  
  //Other way to join string with delimiter
  String str = String.join(",", "JAVA", "DISCOVER", "2018");
  System.out.println("\nOther way : "+str);
  
  
  //List to string
  List<String> list = Arrays.asList("Java", "String", "Joiner");
  String str1 = String.join(", ", list);
  System.out.println("\nList to string : "+str1);
  
  
  //Adding delimiter, prefix and suffix
  StringJoiner sj1 = new StringJoiner(".","Hello "," :)");
  sj1.add("Java");
  sj1.add("Discover");
  sj1.add("2018");
  System.out.println("\nAdding delimiter, prefix and suffix :: "+ sj1.toString());
  
  
  
  /*
   * Using setEmptyValue() method - set default value of the string
   * if string is empty
   */
  StringJoiner sj2 = new StringJoiner("*");   
  sj2.setEmptyValue("DEFUALT EMPTY STRING");
  System.out.println("\nUsing setEmptyValue() method-1 :: "+ sj2.toString() + " ---- LENGTH : "+sj2.toString().length());
  

  // Same after adding some value
  sj2.add("ORACLE");
  sj2.add("LAMBDA");
  System.out.println("\nUsing setEmptyValue() method-2 :: "+ sj2.toString() + " ---- LENGTH : "+sj2.toString().length());
  
  
  
  //Merging 2 string joiner 
  StringJoiner sj3 = sj1.merge(sj2);
  System.out.println("\nMerging 2 string joiner :: "+sj3.toString());
 }
}

OUTPUT:

Joning string by delimiter :: Java,Discover,2018

Other way : JAVA,DISCOVER,2018

List to string : Java, String, Joiner

Adding delimiter, prefix and suffix :: Hello Java.Discover.2018 :)

Using setEmptyValue() method-1 :: DEFUALT EMPTY STRING ---- LENGTH : 20

Using setEmptyValue() method-2 :: ORACLE*LAMBDA ---- LENGTH : 13

Merging 2 string joiner :: Hello Java.Discover.2018.ORACLE*LAMBDA :)

Java 8 - StringJoiner

Java 8 - StringJoiner

StringJoiner  

In Java-8 we got new class called StringJoiner to join multiple strings. Nothing new in StringJoiner class when we compare with already existing classes like StringBuffer and StringBuilder. Only the difference here we can set prefix and suffix along with delimiter, or we can set only delimiter by using different constructor. Lets see simple example as how to use StringJoiner from Java-8.

public class StringJoinerExample {

 public static void main(String[] args) {
  
  StringJoiner sJoin = new StringJoiner(",");
  
  sJoin.add("java");
  sJoin.add("python");
  sJoin.add("C#");
  sJoin.add("scala");
    
  System.out.println(sJoin);
 }
}

OUTPUT:

java,python,C#,scala

public class StringJoinerExample {

 public static void main(String[] args) {
  
  StringJoiner sJoin = new StringJoiner("," ,"{" ,"}");
  
  sJoin.add("java");
  sJoin.add("python");
  sJoin.add("C#");
  sJoin.add("scala");
    
  System.out.println(sJoin);  
 }
}

OUTPUT:

{java,python,C#,scala}