2018.12.18 java22

假设顺序列表ArrayList中存储的元素是整型数字1~5，遍历每个元素，将每个元素顺序输出

public static void main(String[] args) {
		ArrayList<Integer> arr = new ArrayList<>();
		
		arr.add(1);
		arr.add(2);
		
		arr.add(4);
		arr.add(5);
		arr.add(3);
		
		
		for(Object obj:arr) {
			
			System.out.println(obj.toString());
		}
		
		System.out.println(arr);

3、在一个列表中存储以下元素：apple,grape,banana,pear

3.1 返回集合中的最大的和最小的元素
3.2 将集合进行排序，并将排序后的结果打印在控制台上

public class Fruit implements Comparable<Fruit>{
	private String name;

	public Fruit() {
		super();
		// TODO 自动生成的构造函数存根
	}

	@Override
	public String toString() {
		return "Fruit [name=" + name + "]";
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((name == null) ? 0 : name.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Fruit other = (Fruit) obj;
		if (name == null) {
			if (other.name != null)
				return false;
		} else if (!name.equals(other.name))
			return false;
		return true;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Fruit(String name) {
		super();
		this.name = name;
	}

	@Override
	public int compareTo(Fruit arg0) {
		// TODO 自动生成的方法存根
		return this.name.compareTo(arg0.name);
	}
}


public static void main(String[] args) {
		Fruit fru1 = new Fruit("apple");
		Fruit fru2 = new Fruit("grape");
		Fruit fru3 = new Fruit("banana");
		Fruit fru4 = new Fruit("pear");
		
		ArrayList<Fruit> list = new ArrayList<>();
		list.add(fru1);
		list.add(fru2);
		list.add(fru3);
		list.add(fru4);
		
		Fruit max = Collections.max(list);
		System.out.println("Max="+max);
		Fruit min = Collections.min(list);
		System.out.println("Min="+min);
		Collections.sort(list);
		System.out.println(list);

从控制台输入若干个单词（输入回车结束）放入集合中，将这些单词排序后（忽略大小写）打印出来

ArrayList<String> list = new ArrayList<>();
		Scanner in = new Scanner(System.in);
		String s = in.nextLine();
		String[] a = s.split(" ");
		for(int i=0;i < a.length;i++){
			for(int j =i+1;j<a.length;j++){
				if(a[i].compareToIgnoreCase(a[j])>0){
					s = a[i];
					a[i]= a[j];
					a[j] = s;
				}
			}
		}
		for(String o:a){
			list.add(o);
			System.out.println(o);
	}
		System.out.println(list);