Foreach 循环: ArrayList, Primitive data, HashMap

 
import java.util.ArrayList;
import java.util.HashMap; 
import java.util.Map;
 
 
 
 
 
public class ForEachLoop {
 
 
 
public static void main(String[] args) {
 
//Simple object or primitive type data loop
 
String[] names = { "Michal", "Mainel", "Merka" };
 
 
 
for (String name : names) {
 
System.out.println(name);
 
}
 
 
 
//Collection API loop
 
 
 
ArrayList<Integer> numbers = new ArrayList<Integer>();
 
//Autoboxing no need cast or creating object new Integer
 
numbers.add(123);
 
numbers.add(12);
 
numbers.add(12445);
 
 
 
for (Integer number : numbers) {
 
System.out.println(number.toString());
 
}
 
 
 
HashMap<String, Integer> nameAndAges = new HashMap<String, Integer>();
 
nameAndAges.put("Jurka", 18);
 
nameAndAges.put("Mina", 19);
 
nameAndAges.put("Michal", 29);
 
 
 
for (Map.Entry<String, Integer> entry : nameAndAges.entrySet()) {
 
System.out.println("Name : " + entry.getKey() + " age " + entry.getValue());
 
}
 
}
 
 
 
}