java数组的12个方法

最近再微信上看见一篇关于java数组操作的12个方法，特分享一下：

1.  声明一个数组 


Java代码 
String[] aArray = new String[5];  
String[] bArray = {"a","b","c", "d", "e"};  
String[] cArray = new String[]{"a","b","c","d","e"};  




2.  输出一个数组 


Java代码 
int[] intArray = { 1, 2, 3, 4, 5 };  
String intArrayString = Arrays.toString(intArray);  
   
// print directly will print reference value  
System.out.println(intArray);  
// [I@7150bd4d  
   
System.out.println(intArrayString);  
// [1, 2, 3, 4, 5]  




3.  从一个数组创建数组列表 




Java代码 
String[] stringArray = { "a", "b", "c", "d", "e" };  
ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));  
System.out.println(arrayList);  
// [a, b, c, d, e]  




4.  检查一个数组是否包含某个值 




Java代码 
String[] stringArray = { "a", "b", "c", "d", "e" };  
boolean b = Arrays.asList(stringArray).contains("a");  
System.out.println(b);  
// true  




5.  连接两个数组 


Java代码 
int[] intArray = { 1, 2, 3, 4, 5 };  
int[] intArray2 = { 6, 7, 8, 9, 10 };  
// Apache Commons Lang library  
int[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2);  




6.  声明一个内联数组（Array inline） 




Java代码 
method(new String[]{"a", "b", "c", "d", "e"});  




7.  把提供的数组元素放入一个字符串 




Java代码 
// containing the provided list of elements  
// Apache common lang  
String j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");  
System.out.println(j);  
// a, b, c  




8.  将一个数组列表转换为数组 


Java代码 
String[] stringArray = { "a", "b", "c", "d", "e" };  
ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));  
String[] stringArr = new String[arrayList.size()];  
arrayList.toArray(stringArr);  
for (String s : stringArr)  
    System.out.println(s);  




9.  将一个数组转换为集（set） 




Java代码 
Set<String> set = new HashSet<String>(Arrays.asList(stringArray));  
System.out.println(set);  
//[d, e, b, c, a]  




10.  逆向一个数组 


Java代码 
int[] intArray = { 1, 2, 3, 4, 5 };  
ArrayUtils.reverse(intArray);  
System.out.println(Arrays.toString(intArray));  
//[5, 4, 3, 2, 1]  




11.  移除数组中的元素 


Java代码 
int[] intArray = { 1, 2, 3, 4, 5 };  
int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array  
System.out.println(Arrays.toString(removed));  




12.  将整数转换为字节数组 


Java代码 
byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();  
   
for (byte t : bytes) {  
   System.out.format("0x%x ", t);  
}