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关于Java数组的12个最佳方法


 

下面是stackoverflow中关于数组方法的相关问题中,获得最多票数的12个数组操作方法。
  1.  声明一个数组
  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
  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
  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
  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
  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)
  method(new String[]{"a", "b", "c", "d", "e"});
  7.  把提供的数组元素放入一个字符串
  // 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.  将一个数组列表转换为数组
  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);
  9.  将一个数组转换为集(set)
  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
  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
  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
  byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();
  for (byte t : bytes) {
  System.out.format("0x%x ", t);
  }