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.
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Java StringJoiner Example
The following example shows:
- Simple Delimiters Example
- adding prefix and suffix
- Merge Two StringJoiner
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 Main {
public static void main(String[] args) {
delimiterDemonstration();
addingPrefixAndSuffix();
mergeTwoStringJoiner();
}
private static void delimiterDemonstration() {
StringJoiner joinNames = new StringJoiner(","); // passing comma(,) as delimiter
// Adding values to StringJoiner
joinNames.add("John");
joinNames.add("Tom");
joinNames.add("Tony");
joinNames.add("Cap");
System.out.println(joinNames);
joinNames = new StringJoiner("|"); // passing pipe(|) as delimiter
// Adding values to StringJoiner
joinNames.add("John");
joinNames.add("Tom");
joinNames.add("Tony");
joinNames.add("Cap");
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("John");
joinNames.add("Tom");
joinNames.add("Tony");
joinNames.add("Cap");
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("John");
joinNames.add("Tom");
// Creating StringJoiner with :(colon) delimiter
StringJoiner joinNames2 = new StringJoiner(":", "[", "]"); // passing colon(:) and square-brackets as delimiter
// Adding values to StringJoiner
joinNames2.add("Tony");
joinNames2.add("Cap");
// Merging two StringJoiner
StringJoiner merge = joinNames.merge(joinNames2);
System.out.println(merge);
}
}
Output:
John,Tom,Tony,Cap
John|Tom|Tony|Cap
[John,Tom,Tony,Cap]
[John,Tom,Tony:Cap]
Java StringJoiner Class Methods Example
The following example demonstrates the usage of StringJoiner class APIs with examples:
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 Main {
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: 17
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