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 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
【2018.12.18 java22】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{
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 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> 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;
j0){
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);
