0. 聲明一個數(shù)組（Declare an array）
1 2 3 | String[] aArray = new String[5];String[] bArray = {"a","b","c", "d", "e"};String[] cArray = new String[]{"a","b","c","d","e"}; |
1. 在Java中輸出一個數(shù)組（Print an array in Java）
1 2 3 4 5 6 7 8 9 | int[] intArray = { 1, 2, 3, 4, 5 };String intArrayString = Arrays.toString(intArray); // print directly will print reference valueSystem.out.println(intArray);// [I@7150bd4d System.out.println(intArrayString);// [1, 2, 3, 4, 5] |
2. 從數(shù)組中創(chuàng)建數(shù)組列表（Create an ArrayList from an array）
1 2 3 4 | 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] |
3. 檢查數(shù)組中是否包含特定值（Check if an array contains a certain value）
1 2 3 4 | String[] stringArray = { "a", "b", "c", "d", "e" };boolean b = Arrays.asList(stringArray).contains("a");System.out.println(b);// true |
4. 連接兩個數(shù)組（ Concatenate two arrays）
1 2 3 4 | int[] intArray = { 1, 2, 3, 4, 5 };int[] intArray2 = { 6, 7, 8, 9, 10 };// Apache Commons Lang libraryint[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2); |
5. 聲明一個數(shù)組內(nèi)鏈（Declare an array inline ）
1 | method(new String[]{"a", "b", "c", "d", "e"}); |
6. 將數(shù)組元素加入到一個獨立的字符串中（Joins the elements of the provided array into a single String）
1 2 3 4 5 | // containing the provided list of elements// Apache common langString j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");System.out.println(j);// a, b, c |
7. 將數(shù)組列表轉(zhuǎn)換成一個數(shù)組 （Covnert an ArrayList to an array）
1 2 3 4 5 6 | 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. 將數(shù)組轉(zhuǎn)換成一個集合（Convert an array to a set）
1 2 3 | Set<String> set = new HashSet<String>(Arrays.asList(stringArray));System.out.println(set);//[d, e, b, c, a] |
9. 反向數(shù)組（Reverse an array）
1 2 3 4 | int[] intArray = { 1, 2, 3, 4, 5 };ArrayUtils.reverse(intArray);System.out.println(Arrays.toString(intArray));//[5, 4, 3, 2, 1] |
10. 刪除數(shù)組元素（Remove element of an array）
1 2 3 | int[] intArray = { 1, 2, 3, 4, 5 };int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new arraySystem.out.println(Arrays.toString(removed)); |
One more – convert int to byte array
1 2 3 4 5 | byte[] bytes = ByteBuffer.allocate(4).putInt(8).array(); for (byte t : bytes) { System.out.format("0x%x ", t);} |
