Arrays工具类十大常用方法

以下是由 * 网站 投票决出的Java数组最常用的十个方法, 

0. 声明数组

String[] aArray = new String[5];



String[] bArray = {"a","b","c", "d", "e"};



String[] cArray = new String[]{"a","b","c","d","e"};

1. 打印数组

int[] intArray = { 1, 2, 3, 4, 5 };



String intArrayString = Arrays.toString(intArray);







// 直接打印,则会打印出引用对象的Hash值



// [[email protected]



System.out.println(intArray);







// [1, 2, 3, 4, 5]



System.out.println(intArrayString);

2. 根据数组创建ArrayList

String[] stringArray = { "a", "b", "c", "d", "e" };



ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));



// [a, b, c, d, e]



System.out.println(arrayList);

3. 检查数组是否包含某个值

String[] stringArray = { "a", "b", "c", "d", "e" };



boolean b = Arrays.asList(stringArray).contains("a");



// true



System.out.println(b);

4. 合并连接两个数组

int[] intArray = { 1, 2, 3, 4, 5 };




int[] intArray2 = { 6, 7, 8, 9, 10 };



// Apache Commons Lang 库




int[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2);

5. 声明内联数组

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

6. 用给定的字符串连结(join)数组

// containing the provided list of elements



// Apache common lang



String j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");



// a, b, c



System.out.println(j);

7. 将ArrayList转换为数组

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);

8. 将数组转换为Set

Set<String> set = new HashSet<String>(Arrays.asList(stringArray));



//[d, e, b, c, a]



System.out.println(set);

9. 数组元素反转

int[] intArray = { 1, 2, 3, 4, 5 };



ArrayUtils.reverse(intArray);



//[5, 4, 3, 2, 1]



System.out.println(Arrays.toString(intArray));

10. 移除元素

int[] intArray = { 1, 2, 3, 4, 5 };




int[] removed = ArrayUtils.removeElement(intArray, 3);//创建新的数组




System.out.println(Arrays.toString(removed));

更多——转换int值为字节数组

byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();








for (byte t : bytes) {



   System.out.format("0x%x ", t);



}

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