数组基础：http://www.cnblogs.com/mengdd/archive/2013/01/04/2844264.html
import java.util.Arrays;
1):创建数组
1 String[] a = new String[5];
2 String[] b = {"a","b","c", "d", "e"};
3 String[] c = new String[]{"a","b","c","d","e"};
2):输出数组
1 import java.util.*;
2 class js
3 {
4 public static void main(String[] args)
5 {
6 int[] a = { 1, 2, 3, 4, 5 };
7 String b = Arrays.toString(a);
8
9 // print directly will print reference value
10 System.out.println(a);
11 // [[email protected]
12
13 System.out.println(b);
14 // [1, 2, 3, 4, 5]
15 }
16 }
3):从一个数组创建数组列表
1 String[] a = { "a", "b", "c", "d", "e" };
2 ArrayList<String> List = new ArrayList<String>(Arrays.asList(a));
3 System.out.println(List);
4 // [a, b, c, d, e]
4):检查一个数组是否包含某个值
1 String[] stringArray = { "a", "b", "c", "d", "e" };
2 boolean b = Arrays.asList(stringArray).contains("a");
3 System.out.println(b);
4 // true
5):连接两个数组
1 int[] a = { 1, 2, 3, 4, 5 }; 2 int[] b = { 6, 7, 8, 9, 10 }; 3 int[] c = ArrayUtils.addAll(a,b);
6):声明一个内联数组
1 method(new String[]{"a", "b", "c", "d", "e"});
7):把提供的一个数组放入字符串
1 String j = StringUtils.join(new String[] { "a", "b", "c" }, ", "); 2 System.out.println(j); 3 // a, b, c
8):将一个数组列表转化为数组
1 String[] a = { "a", "b", "c", "d", "e" };
2 ArrayList<String> aList = new ArrayList<String>(Arrays.asList(a));
3 String[] b = new String[aList.size()];
4 aList.toArray(b);
5 for (String s : b)
6 System.out.println(s);
9):将一个数组转化为集(set)
1 Set<String> set = new HashSet<String>(Arrays.asList(stringArray)); 2 System.out.println(set); 3 //[d, e, b, c, a]
10):逆向一个数组
1 int[] intArray = { 1, 2, 3, 4, 5 };
2 ArrayUtils.reverse(intArray);
3 System.out.println(Arrays.toString(intArray));
4 //[5, 4, 3, 2, 1]
11):移除数组中的元素
1 int[] intArray = { 1, 2, 3, 4, 5 };
2 int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array
3 System.out.println(Arrays.toString(removed));
12):将整数转换为字节数组
1 byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();
2 for (byte t : bytes) {
3 System.out.format("0x%x ", t);
4 }
时间： 2024-10-03 23:16:08