- String[] aArray = new String[5];
- String[] bArray = {"a","b","c", "d", "e"};
- String[] cArray = new String[]{"a","b","c","d","e"};
2. 輸出一個數組
- 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. 從一個數組創建數組列表
- 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. 檢查一個數組是否包含某個值
- String[] stringArray = { "a", "b", "c", "d", "e" };
- boolean b = Arrays.asList(stringArray).contains("a");
- System.out.println(b);
- // true
5. 連接兩個數組
- 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. 聲明一個內聯數組(Array inline)
- method(new String[]{"a", "b", "c", "d", "e"});
7. 把提供的數組元素放入一個字符串
- // 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. 將一個數組列表轉換爲數組
- 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. 將一個數組轉換爲集(set)
- Set<String> set = new HashSet<String>(Arrays.asList(stringArray));
- System.out.println(set);
- //[d, e, b, c, a]
10. 逆向一個數組
- int[] intArray = { 1, 2, 3, 4, 5 };
- ArrayUtils.reverse(intArray);
- System.out.println(Arrays.toString(intArray));
- //[5, 4, 3, 2, 1]
11. 移除數組中的元素
- int[] intArray = { 1, 2, 3, 4, 5 };
- int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array
- System.out.println(Arrays.toString(removed));
12. 將整數轉換爲字節數組
- byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();
- for (byte t : bytes) {
- System.out.format("0x%x ", t);
- }