Java 8 ForEach Example __java

In this article, we'll show you how to loop through a list and a map with the Java 8 new features ForEach.

1. ForEach and Map

1.1 Normal way to loop a Map.

	map<string, integer> items = new hashmap<> ();
	Items.put ("A");
	Items.put ("B");
	Items.put ("C");
	Items.put ("D",);
	Items.put ("E", m);
	Items.put ("F",);

	For (map.entry<string, integer> entry:items.entrySet ()) {
		System.out.println ("Item:" + entry.getkey () + "Co") UNT: "+ entry.getvalue ());
	}

1.2 In Java 8, you can loop through a map with a foreach + lambda expression.

	map<string, integer> items = new hashmap<> ();
	Items.put ("A");
	Items.put ("B");
	Items.put ("C");
	Items.put ("D",);
	Items.put ("E", m);
	Items.put ("F",);
	
	Items.foreach ((k,v)->system.out.println ("Item:" + k + "Count:" + V));
	
	Items.foreach ((k,v)->{
		System.out.println ("Item:" + k + "Count:" + V);
		if ("E". Equals (k)) {
			System.out.println ("Hello E");
		}
	);

2. ForEach and List

2.1 Normally use a For loop to loop through a List.

	list<string> items = new arraylist<> ();
	Items.Add ("A");
	Items.Add ("B");
	Items.Add ("C");
	Items.Add ("D");
	Items.Add ("E");

	for (String item:items) {
		System.out.println (item);
	}

2.2 In Java 8, you can loop through a list with a ForEach + lambda expression or a method reference.

 list<string> items = new arraylist<> ();
	Items.Add ("A");
	Items.Add ("B");
	Items.Add ("C");
	Items.Add ("D");

	Items.Add ("E");
		
	Lambda//output:a,b,c,d,e Items.foreach (item->system.out.println (item));
		Output:c Items.foreach (item->{if ("C". Equals (item)) {SYSTEM.OUT.PRINTLN (item);
		
	}
	});
	
	Method Reference//output:a,b,c,d,e Items.foreach (system.out::p rintln); Stream and Filter//output:b Items.stream (). Filter (S->s.contains ("B")). ForEach (System.out::p rintln);