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Arrays工具类十大常用方法
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
// [I@7150bd4d
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);
}
Arrays工具类十大常用方法