ArrayList复制

1，已有集合A，新建集合B，希望将A中内容完整复制到B public class Person implements Cloneable{ private String name; private String hobby; private int age; public Person(String name, String hobby, int age) { this.name = name; this.hobby = hobby; this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getHobby() { return hobby; } public void setHobby(String hobby) { this.hobby = hobby; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } @Override public String toString() { return "habaobei{" + "name='" + name + '\'' + ", hobby='" + hobby + '\'' + ", age=" + age + '}'; } public Person clone(){ try { return (Person)super.clone(); }catch (Exception var2) { return null; } } }  通过addAll()方法，实现复制， private static void testCloneForlist(){ ArrayList qiao = new ArrayList<>(); qiao.add(new Person("qiao haha","maimaimai",18)); qiao.add(new Person("sha haha","maimaimai",19)); List qiaosan = new ArrayList<>(); List qiaosan2 = new ArrayList<>(); qiaosan2.addAll(qiao);//addAll() for (Person habaobei :qiao) { Person haha = habaobei.clone(); haha.setAge(20); qiaosan.add(haha); } System.out.println(qiao); System.out.println(qiaosan); System.out.println(qiaosan2);   for (Person habaobei :qiao) { habaobei.setAge(21); } System.out.println(qiao); } 类的复制，需要实现Cloneable，重写clone方法