Java 笔记

1、for循环的三种用法

　　1.1

1 int[] integers = {1, 2, 3, 4}; 
2 for (int j = 0; j < integers.length; j++) {  
3   int i = integers[j];  
4   System.out.println(i);  
5 }

　　1.2

1 String[] strings = {"A", "B", "C", "D"};  
2 Collection stringList = java.util.Arrays.asList(strings);  
3 for (Iterator itr = stringList.iterator(); itr.hasNext();) {  
4   Object str = itr.next();  
5   System.out.println(str);  
6 }

　　1.3

1 int[] integers = {1, 2, 3, 4};  
2 for (int i : integers) {  
3   System.out.println(i);
4 }