In this post, we will learn “How to sort a stream of numbers, strings and list in Java 8?”.
Sorting of a Stream in Java 8...!!! Share on X
In this tutorial, we are going to cover below topics:
- Sorting of stream of number in Ascending(Natural) Order
- Sorting of stream of number in Descending(Reverse) Order
- Sorting of stream of string in Ascending Order
- Sorting of stream of string in Descending Order
- Sorting of stream of list in Ascending Order
- Sorting of stream of list custom object in Ascending Order
Let’s begin:
1. Sort number in natural order
import java.util.Comparator;
import java.util.stream.Stream;
public class Number_Sort_Stream_Java8_Example1 {
public static void main(String[] args) {
System.out.println("Sorted stream of Numbers in Ascending Order Example");
Stream <Integer> numberStream = Stream.of(54, 22, 78, 11, 9);
numberStream.sorted(Comparator.naturalOrder())
.forEach(System.out::println);
}
}
Output:
Sorted stream of Numbers in Ascending Order Example 9 11 22 54 78
2. Sort number in reverse order
import java.util.Comparator;
import java.util.stream.Stream;
public class Number_Sort_Stream_Java8_Example2 {
public static void main(String[] args) {
System.out.println("Sorted stream of Numbers in Descending Order Example");
Stream <Integer> numberStream = Stream.of(54, 22, 78, 11, 9);
numberStream.sorted(Comparator.reverseOrder())
.forEach(System.out::println);
}
}
Output:
Sorted stream of Numbers in Descending Order Example 78 54 22 11 9
3. Sort string in natural order
import java.util.Comparator;
import java.util.stream.Stream;
public class String_Sort_Stream_Java8_Example1 {
public static void main(String[] args) {
System.out.println("Sorted stream of Strings in Ascending Order Example");
Stream <String> stringStream = Stream.of("Tom", "Mark", "Lucas", "Amber", "Cash", "Joey");
stringStream.sorted(Comparator.naturalOrder())
.forEach(System.out::println);
}
}
Output:
Sorted stream of Strings in Ascending Order Example Amber Cash Joey Lucas Mark Tom
4. Sort string in reverse order
import java.util.Comparator;
import java.util.stream.Stream;
public class String_Sort_Stream_Java8_Example2 {
public static void main(String[] args) {
System.out.println("Sorted stream of Strings in Descending Order Example");
Stream <String> stringStream = Stream.of("Tom", "Mark", "Lucas", "Amber", "Cash", "Joey");
stringStream.sorted(Comparator.reverseOrder())
.forEach(System.out::println);
}
}
Output:
Sorted stream of Strings in Descending Order Example Tom Mark Lucas Joey Cash Amber
5. Sort list in natural order
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
public class List_Sort_Stream_Java8_Example1 {
public static void main(String[] args) {
List <String> listOfStudents = Arrays.asList("Tom", "Mark", "Lucas", "Amber", "Cash", "Joey");
System.out.println("Before Sorting:\n");
for (String s: listOfStudents) {
System.out.println(s);
}
System.out.println("\nAfter Sorting:\n");
//Sort the list directly using Lambda expression
listOfStudents.stream().sorted(Comparator.naturalOrder())
.forEach(System.out::println);;
}
}
Output:
Before Sorting: Tom Mark Lucas Amber Cash Joey After Sorting: Amber Cash Joey Lucas Mark Tom
6. Sort custom list object
import java.util.ArrayList;
import java.util.List;
public class List_Sort_Stream_Java8_Example2 {
public static void main(String[] args) {
List <Actor> listOfActors = getActors();
System.out.println("Before Sorting:\n");
for (Actor actor: listOfActors) {
System.out.println(actor.getAge() + "---" + actor.getName());
}
System.out.println("\nAfter Sorting:\n");
//Sort the list directly using Lambda expression
listOfActors.sort((Actor a1, Actor a2) -> a1.getAge() - a2.getAge());
//Print the sorted list using Java 8 foreach method
listOfActors.forEach((actor) -> System.out.println(actor.getAge() + "---" + actor.getName()));
}
static List <Actor> getActors() {
List <Actor> actors = new ArrayList <Actor> ();
actors.add(new Actor(5, "yashu"));
actors.add(new Actor(64, "gaurangee"));
actors.add(new Actor(22, "pulkit"));
actors.add(new Actor(93, "isha"));
actors.add(new Actor(8, "deepak"));
actors.add(new Actor(44, "yogi"));
actors.add(new Actor(87, "yashi"));
return actors;
}
}
class Actor {
int age;
String name;
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Actor(int age, String name) {
this.name = name;
this.age = age;
}
}
Output:
Before Sorting: 5---yashu 64---gaurangee 22---pulkit 93---isha 8---deepak 44---yogi 87---yashi After Sorting: 5---yashu 8---deepak 22---pulkit 44---yogi 64---gaurangee 87---yashi 93---isha
See, how elegant and powerful Java 8 is.
Sorting of a Stream in Java 8...!!! Share on X
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