package com.imooc;
class Student{
public void study(){
System.out.println("学生学习");
}
}
class StudentDemo{
public Student getStudent(){
return new Student();
}
}
public class ReturnDemo {
public static void main(String[] args){
StudentDemo sd = new StudentDemo();
Student s = sd.getStudent();
s.study();
}
}
抽象类作为返回值类型，返回的是该抽象类的子类对象
package com.imooc;
abstract class Person{
public abstract void study();
}
class Student extends Person{
public void study(){
System.out.println("学生爱学习");
}
}
class StudentDemo{
public Person getPerson(){
return new Student();
}
}
public class ReturnDemo {
public static void main(String[] args){
StudentDemo sd = new StudentDemo();
Person p = sd.getPerson();
p.study();
}
}
接口作为返回返回值类型，返回的是实现该接口的实现类的对象
package com.imooc;
interface Love{
public abstract void love();
}
class Teacher implements Love{
public void love(){
System.out.println("老师爱上课");
}
}
class TeacherDemo{
public Love getLove(){
return new Teacher(); //因为teacher实现了Love接口
}
}
public class TeacherTest {
public static void main(String[] args){
TeacherDemo td = new TeacherDemo();
Love l = td.getLove();
l.love();
}
}
如果每次调用完方法都返回一个对象，那么便可以实现链式编程
例如：
package com.imooc;
interface Love{
public abstract void love();
}
class Teacher implements Love{
public void love(){
System.out.println("老师爱上课");
}
}
class TeacherDemo{
public Love getLove(){
return new Teacher(); //因为teacher实现了Love接口
}
}
public class TeacherTest {
public static void main(String[] args){
TeacherDemo td = new TeacherDemo();
Love l = td.getLove();
l.love(); //链式编程：每次调用完方法之后返回的是一个对象
td.getLove().love();
//td是一个对象，td.getLovce()返回的是一个实现Love接口的对象，
//可以再调用这个对象的方法
}
}