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超实用的Java数组技巧攻略


 

        本文分享了关于Java数组最顶级的11大方法,帮助你解决工作流程问题,无论是运用在团队环境或是在私人项目中,你都可以直接拿来用! 

 
0.  声明一个数组(Declare an array) 
 
String[] aArray = new String[5];
String[] bArray = {"a","b","c", "d", "e"};
String[] cArray = new String[]{"a","b","c","d","e"};
 
 
 
1.  在Java中输出一个数组(Print an array in Java)
 
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]
 
 
 
 
 
2. 从数组中创建数组列表(Create an ArrayList from an array)
 
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. 检查数组中是否包含特定值(Check if an array contains a certain value)
 
String[] stringArray = { "a", "b", "c", "d", "e" };
boolean b = Arrays.asList(stringArray).contains("a");
System.out.println(b);
// true
 
 
 
 
4. 连接两个数组( Concatenate two arrays)
 
int[] intArray = { 1, 2, 3, 4, 5 };
int[] intArray2 = { 6, 7, 8, 9, 10 };
// Apache Commons Lang library
int[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2);
5. 声明一个数组内链(Declare an array inline )
 
method(new String[]{"a", "b", "c", "d", "e"});
 
 
 
 
6. 将数组元素加入到一个独立的字符串中(Joins the elements of the provided array into a 
 
single String)
 
 
// 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
 
 
7. 将数组列表转换成一个数组 (Covnert an ArrayList to an array) 
 
 
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. 将数组转换成一个集合(Convert an array to a set) 
 
Set<String> set = new HashSet<String>(Arrays.asList(stringArray));
System.out.println(set);
//[d, e, b, c, a]
 
 
 
 
 
9. 反向数组(Reverse an array)
 
int[] intArray = { 1, 2, 3, 4, 5 };
ArrayUtils.reverse(intArray);
System.out.println(Arrays.toString(intArray));
//[5, 4, 3, 2, 1]
 
 
 
 
 
10. 删除数组元素(Remove element of an array)
 
int[] intArray = { 1, 2, 3, 4, 5 };
int[] removed = ArrayUtils.removeElement(intArray, 3);
//create a new array
System.out.println(Arrays.toString(removed));
 
 
 
One more – convert int to byte array 
 
byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();
  
for (byte t : bytes) {
   System.out.format("0x%x ", t);
}