Java编程泛型限定代码分享

package newFeatures8;import java.util.*;class GenericDemo6 {public static void main(String[] args) {//ArrayList<Person> al = new ArrayList<Student>();error//为了解决等号两边泛型不一致的情况，jdk1.7以后可以这么写ArrayList<Person> al = new ArrayList<>();//右边的泛型自动反射进来al.add(new Person("abc1"));al.add(new Person("abc2"));al.add(new Person("abc3"));// printColl(al);ArrayList<Student> al1 = new ArrayList<Student>();al1.add(new Student("abc--1"));al1.add(new Student("abc--2"));al1.add(new Student("abc--3"));printColl(al1); }public static void printColl(Collection<? extends Person> al) {Iterator<? extends Person> it = al.iterator();while (it.hasNext()) {System.out.println(it.next().getName());}}}class Person {private String name;Person(String name) {this.name = name;}public String getName() {return name;}}class Student extends Person {Student(String name) {super(name);}}