package cn.Tim.org; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Set; import org.junit.Test; public class ForeachDemo1 { @Test public void ArrayTest() { int arr[] = {1,2,3}; for(int i: arr) { System.out.println(i); } } @Test public void SetTest() { List list = new ArrayList(); list.add(1); list.add(2); list.add(3); for(Object obj : list) { int i = (Integer) obj; System.out.println(i); } } @Test public void MapOldTest() { Map map = new HashMap(); map.put(1, "one"); map.put(2, "two"); map.put(3, "three"); //通过keySet迭代Map Set set = map.keySet(); Iterator it = set.iterator(); while(it.hasNext()) { Integer key = (Integer)it.next(); String value = (String)map.get(key); System.out.println(key + ":" + value); } //通过entrySet迭代Map Set set1 = map.entrySet(); Iterator it1 = set1.iterator(); while(it1.hasNext()) { Map.Entry entry = (Map.Entry) it1.next(); Integer key = (Integer)entry.getKey(); String value = (String)entry.getValue(); System.out.println(key + ":" + value); } } @Test public void MapNewTest() { Map map = new HashMap(); map.put(1, "one"); map.put(2, "two"); map.put(3, "three"); //通过keySet,for-each来迭代Map for(Object obj : map.keySet()) { Integer key = (Integer)obj; String value = (String)map.get(key); System.out.println(key + ":" + value); } //通过entrySet,for-each来迭代Map for(Object obj : map.entrySet()) { Map.Entry entry = (Map.Entry) obj; Integer key = (Integer)entry.getKey(); String value = (String)entry.getValue(); System.out.println(key + ":" + value); } } }