Java 笔记

1、for循环的三种用法

　　1.1

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

　　1.2

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

　　1.3

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