Java added a new final class StringJoiner in java.util package. It is used to construct a sequence of characters separated by a delimiter. Now, you can create a string by passing delimiters like a comma(,), hyphen(-) etc.
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| Java 8 StringJoiner Class |
You can also pass prefix and suffix to the char sequence. In this post, we will learn how to use StringJoiner with examples.
StringJoiner Example 1: Simple Delimiters Example
import java.util.StringJoiner;
public class StringJoinerExample{
public static void main(String []args){
delimiterDemonstration();
}
private static void delimiterDemonstration() {
StringJoiner joinNames = new StringJoiner(","); // passing comma(,) as delimiter
// Adding values to StringJoiner
joinNames.add("John");
joinNames.add("Tony");
joinNames.add("Amir");
joinNames.add("Prabhas");
System.out.println(joinNames);
joinNames = new StringJoiner("|"); // passing comma(,) as delimiter
// Adding values to StringJoiner
joinNames.add("John");
joinNames.add("Tony");
joinNames.add("Amir");
joinNames.add("Prabhas");
System.out.println(joinNames);
}
}
Output:
John,Tony,Amir,Prabhas
John|Tony|Amir|PrabhasStringJoiner Example 2: adding prefix and suffix
import java.util.StringJoiner;
/**
* Java added a new final class StringJoiner in java.util package. It is used to construct
* a sequence of characters separated by a delimiter
* @author RAMESH
*
*/
public class StringJoinerClassExample {
public static void main(String[] args) {
addingPrefixAndSuffix();
}
private static void addingPrefixAndSuffix() {
// passing comma(,) and
// square-brackets as
// delimiter
StringJoiner joinNames = new StringJoiner(",", "[", "]");
// Adding values to StringJoiner
joinNames.add("Ramesh");
joinNames.add("Tony");
joinNames.add("Stark");
joinNames.add("John");
System.out.println(joinNames);
}
}
Output:
[Ramesh,Tony,Stark,John]StringJoiner Example 3: Merge Two StringJoiner
The merge() method merges two StringJoiner objects excluding of prefix and suffix of the second StringJoiner object.
import java.util.StringJoiner;
/**
* Java added a new final class StringJoiner in java.util package. It is used to construct
* a sequence of characters separated by a delimiter
* @author RAMESH
*
*/
public class StringJoinerClassExample {
public static void main(String[] args) {
mergeTwoStringJoiner();
}
private static void mergeTwoStringJoiner(){
// passing comma(,) and square-brackets as delimiter
StringJoiner joinNames = new StringJoiner(",", "[", "]");
// Adding values to StringJoiner
joinNames.add("Rahul");
joinNames.add("Raju");
// Creating StringJoiner with :(colon) delimiter
StringJoiner joinNames2 = new StringJoiner(":", "[", "]"); // passing colon(:) and square-brackets as delimiter
// Adding values to StringJoiner
joinNames.add("Stark");
joinNames.add("John");
// Merging two StringJoiner
StringJoiner merge = joinNames.merge(joinNames2);
System.out.println(merge);
}
}
Output:
[Rahul,Raju,Stark,John]StringJoiner Example 4: StringJoiner Methods
import java.util.StringJoiner;
/**
* Java added a new final class StringJoiner in java.util package. It is used to construct
* a sequence of characters separated by a delimiter
* @author RAMESH
*
*/
public class StringJoinerClassExample {
public static void main(String[] args) {
stringJoinerMethods();
}
private static void stringJoinerMethods(){
StringJoiner joinNames = new StringJoiner(","); // passing comma(,) as delimiter
// Prints nothing because it is empty
System.out.println(joinNames);
// We can set default empty value.
joinNames.setEmptyValue("It is empty");
System.out.println(joinNames);
// Adding values to StringJoiner
joinNames.add("Rahul");
joinNames.add("Raju");
System.out.println(joinNames);
// Returns length of StringJoiner
int length = joinNames.length();
System.out.println("Length: "+length);
// Returns StringJoiner as String type
String str = joinNames.toString();
System.out.println(str);
// Now, we can apply String methods on it
char ch = str.charAt(3);
System.out.println("Character at index 3: "+ch);
// Adding one more element
joinNames.add("Sorabh");
System.out.println(joinNames);
// Returns length
int newLength = joinNames.length();
System.out.println("New Length: "+newLength);
}
}
Output:
It is empty
Rahul,Raju
Length: 10
Rahul,Raju
Character at index 3: u
Rahul,Raju,Sorabh
New Length: 17Complete Example for Reference
import java.util.StringJoiner;
/**
* Java added a new final class StringJoiner in java.util package. It is used to construct
* a sequence of characters separated by a delimiter
* @author RAMESH
*
*/
public class StringJoinerClassExample {
public static void main(String[] args) {
delimiterDemonstration();
addingPrefixAndSuffix();
mergeTwoStringJoiner();
stringJoinerMethods();
}
private static void delimiterDemonstration() {
StringJoiner joinNames = new StringJoiner(","); // passing comma(,) as delimiter
// Adding values to StringJoiner
joinNames.add("Ramesh");
joinNames.add("Tony");
joinNames.add("Stark");
joinNames.add("John");
System.out.println(joinNames);
joinNames = new StringJoiner("|"); // passing comma(,) as delimiter
// Adding values to StringJoiner
joinNames.add("Ramesh");
joinNames.add("Tony");
joinNames.add("Stark");
joinNames.add("John");
System.out.println(joinNames);
}
private static void addingPrefixAndSuffix() {
// passing comma(,) and
// square-brackets as
// delimiter
StringJoiner joinNames = new StringJoiner(",", "[", "]");
// Adding values to StringJoiner
joinNames.add("Ramesh");
joinNames.add("Tony");
joinNames.add("Stark");
joinNames.add("John");
System.out.println(joinNames);
}
private static void mergeTwoStringJoiner(){
// passing comma(,) and square-brackets as delimiter
StringJoiner joinNames = new StringJoiner(",", "[", "]");
// Adding values to StringJoiner
joinNames.add("Rahul");
joinNames.add("Raju");
// Creating StringJoiner with :(colon) delimiter
StringJoiner joinNames2 = new StringJoiner(":", "[", "]"); // passing colon(:) and square-brackets as delimiter
// Adding values to StringJoiner
joinNames.add("Stark");
joinNames.add("John");
// Merging two StringJoiner
StringJoiner merge = joinNames.merge(joinNames2);
System.out.println(merge);
}
private static void stringJoinerMethods(){
StringJoiner joinNames = new StringJoiner(","); // passing comma(,) as delimiter
// Prints nothing because it is empty
System.out.println(joinNames);
// We can set default empty value.
joinNames.setEmptyValue("It is empty");
System.out.println(joinNames);
// Adding values to StringJoiner
joinNames.add("Rahul");
joinNames.add("Raju");
System.out.println(joinNames);
// Returns length of StringJoiner
int length = joinNames.length();
System.out.println("Length: "+length);
// Returns StringJoiner as String type
String str = joinNames.toString();
System.out.println(str);
// Now, we can apply String methods on it
char ch = str.charAt(3);
System.out.println("Character at index 3: "+ch);
// Adding one more element
joinNames.add("Sorabh");
System.out.println(joinNames);
// Returns length
int newLength = joinNames.length();
System.out.println("New Length: "+newLength);
}
}
Output:
Ramesh,Tony,Stark,John
Ramesh|Tony|Stark|John
[Ramesh,Tony,Stark,John]
[Rahul,Raju,Stark,John]
It is empty
Rahul,Raju
Length: 10
Rahul,Raju
Character at index 3: u
Rahul,Raju,Sorabh
New Length: 17Source code on GitHub
The source code of this post is available on GitHub Repository.
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