java data structure -API collection of tools commonly used methods

java data structure -API collection of tools commonly used methods

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class CollectionsTest {
	public static void main(String[] args) {
		List<Integer> list = new ArrayList<Integer>();
		list.add(12);
		list.add(-15);
		list.add(7);
		list.add(4);
		list.add(35);
		list.add(9);
		
		System.out.println("源列表：" + list);

		// 最大值
		System.out.println("最大值：" + Collections.max(list));
		
		// 最小值
		System.out.println("最小值：" + Collections.min(list));
		
		// 替换
		Collections.replaceAll(list, -15, 12);
		System.out.println("-15替换12：" + list);
 
		// 出现次数
		System.out.println("12出现次数：" + Collections.frequency(list, 12));

		// 排序（自然顺序）
		Collections.sort(list);
		System.out.println("自然序：" + list);
		
		// 逆序
		Collections.reverse(list);
		System.out.println("逆序：" + list);
		
		
		// 随机排序
		Collections.shuffle(list);
		System.out.println("随机序：" + list);
		
		// 定制排序的用法，将int类型转成string进行比较
		Collections.sort(list, new Comparator<Object>() {
			@Override
			public int compare(Object o1, Object o2) {
				String str1 = String.valueOf(o1);
				String str2 = String.valueOf(o2);
				
				return str1.compareTo(str2);
			}
		});
		System.out.println("定制序：" + list);
		
		// 根据指定的距离轮换指定列表中的元素。即旋转，当distance为正数时，将list后distance个元素整体移到前面；当distance为负数时，将list的前distance个元素整体移到后面。
		Collections.rotate(list, 3);
		System.out.println("旋转3：" + list);
		
		Collections.rotate(list, -3);
		System.out.println("旋转-3：" + list);
		
		Collections.sort(list);		
		
		// 二分查找
		System.out.println("-15下标：" + Collections.binarySearch(list, -15));
		System.out.println("7下标：" + Collections.binarySearch(list, 7));
		System.out.println("35下标：" + Collections.binarySearch(list, 35));
	
        //copy(List m,List n)方法的使用(含义：将集合n中的元素全部复制到m中,并且覆盖相应索引的元素)。
		List m = Arrays.asList("one two three four five six siven".split(" "));
		Collections.swap(m, 2, 3);
		System.out.println(m);
		List n = Arrays.asList("我 是 复制过来的哈".split(" "));
        Collections.copy(m,n);
        System.out.println(m);
        Collections.fill(m, "啊啊啊");
        System.out.println(m);
	}
	
}