JAVA的集合框架与迭代器的测试------JAVA

清疚 2024-03-22 14:53 96阅读 0赞

>     import java.util.*;
>     
>     public class L
>     {
>         public static void main(String[] args)
>         {
>             Collection c = new ArrayList();
>             c.add("aa");
>             c.add(128);
>             c.add("尚硅谷");
>             c.add(1.0);
>             c.add(new Object());
>             c.add(new Person("sd",12));
>             System.out.println(c);
>             Collection c1 = new ArrayList();
>             c1.add(3.0);
>             c1.add(2.0);
>             c.addAll(c1);
>             c.add(c1);
>             System.out.println(c);
>             System.out.println(c.size());
>             System.out.println(c.isEmpty());
>             System.out.println(c.contains("aa"));
>             System.out.println(c.contains(1.0));
>             System.out.println(c.contains(128));
>             System.out.println(c.contains(new Person("sd",12)));
>             c1.remove(2.0);
>             Object[] o = c.toArray();
>             System.out.println(Arrays.toString(o));
>             String[] arr = new String[]{"AA","bb","CC"};
>             Collection list = Arrays.asList(arr);
>             System.out.println(list);
>             list = Arrays.asList("AAi","bbi","CCi");
>             System.out.println(list);
>             Integer[] arr1 = new Integer[]{1,2,3};
>             List list1 = Arrays.asList(arr1);
>             System.out.println(list1.size());
>             System.out.println(list1);
>             int[] arr2 = new int[]{1,2,3};
>             List list2 = Arrays.asList(arr2);
>             System.out.println(list2.size());
>             System.out.println(list2);
>         }
>     }
>     
>     class Person
>     {
>         String name;
>         int age;
>         public Person() {
>         }
>         public Person(String name, int age) {
>             this.name = name;
>             this.age = age;
>         }
>     
>         public String getName() {
>             return name;
>         }
>     
>         public void setName(String name) {
>             this.name = name;
>         }
>     
>         public int getAge() {
>             return age;
>         }
>     
>         public void setAge(int age) {
>             this.age = age;
>         }
>     
>         @Override
>         public String toString() {
>             return "Person{" +
>                     "name='" + name + '\'' +
>                     ", age=" + age +
>                     '}';
>         }
>     
>         @Override
>         public boolean equals(Object o) {
>             if (this == o) return true;
>             if (!(o instanceof Person person)) return false;
>             return getAge() == person.getAge() && Objects.equals(getName(), person.getName());
>         }
>     }
> 
>     import java.sql.SQLOutput;
>     import java.util.*;
>     
>     public class IteratorTest
>     {
>         public static void main(String[] args)
>         {
>             Collection c = new ArrayList();
>             c.add("aa");
>             c.add(128);
>             c.add(new String("尚硅谷"));
>             c.add("尚硅谷");
>             c.add(1.0);
>             c.add(new Object());
>             Iterator iterator = c.iterator();
>     //        for (int i = 0; i < c.size(); i++)
>     //        {
>     //            System.out.println(iterator.next());
>     //        }
>             while(iterator.hasNext())
>             {
>                 System.out.println(iterator.next());
>             }
>             //错误的
>     //        while((iterator.next()) != null)
>     //        {
>     //            System.out.println(iterator.next());
>     //        }
>             for(Object obj : c)
>             {
>                 System.out.println(obj);
>             }
>             int[] arr = new int[]{1,2,2,3,4,5};
>             for(int i : arr)
>             {
>                 System.out.println(i);
>             }
>             String[] arr3 = new String[]{"aa","bb","cc","ss"};
>             for(String s : arr3)
>             {
>                 System.out.println(s);
>             }
>             //for-each循环底层仍然使用iterator(迭代器)
>             //增强for循环无法修改索引元素
>             List list = new ArrayList();
>             list.add("aA");
>             list.add(123);
>             list.add("BB");
>             list.add(new Person("tom",12));
>             System.out.println(list.toString());
>             list.add(2,"CC");
>             System.out.println(list);
>             List list1 = Arrays.asList(1,2,3);
>             list.addAll(1,list1);
>             //将list1作为整体插入
>             list.add(1,list1);
>             System.out.println(list);
>             List list2 = new ArrayList();
>             list.add("AA");
>             list.add("BB");
>             list.add(1223);
>             list.add(2);
>             list.add(new Person("tOM",12));
>             list.remove(2);
>             System.out.println(list);
>             System.out.println(list.get(2));
>             Iterator iterator1 = list.iterator();
>             while(iterator1.hasNext() == true)
>             {
>                 System.out.println(iterator1.next());
>             }
>             for(Object obj : list)
>             {
>                 System.out.println(obj);
>             }
>             for (int i = 0; i < list.size(); i++)
>             {
>                 System.out.println(list.get(i));
>             }
>     
>         }
>     }