Java数组的12个常用方法

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"};

打印一个数组

Java数组的12个常用方法
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]
Java数组的12个常用方法

根据数组创建ArrayList

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]

判断数组内部是否包含某个值

String[] stringArray = { "a", "b", "c", "d", "e" };
boolean b = Arrays.asList(stringArray).contains("a");
System.out.println(b);
// true

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);

声明一个内联数组(array inline)

method(new String[]{"a", "b", "c", "d", "e"});

根据分隔符拼接数组元素(去掉最后一个分隔符)

// 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

ArrayList转数组

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);

Array转Set

Set<String> set = new HashSet<String>(Arrays.asList(stringArray));
System.out.println(set);
//[d, e, b, c, a]

反转数组

int[] intArray = { 1, 2, 3, 4, 5 };
ArrayUtils.reverse(intArray);
System.out.println(Arrays.toString(intArray));
//[5, 4, 3, 2, 1]

删除数组元素

int[] intArray = { 1, 2, 3, 4, 5 };
int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array
System.out.println(Arrays.toString(removed));

整形转字节数组

byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();
for (byte t : bytes) {
    System.out.format("0x%x ", t);
}

 

本文转自风一样的码农博客园博客,原文链接:http://www.cnblogs.com/chenpi/p/5507806.html,如需转载请自行联系原作者

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