Java中父类和子类之间的转换操作示例

这篇文章主要介绍了Java中父类和子类之间的转换操作,结合实例形式分析了Java中父类和子类之间的转换相关原理、操作技巧与使用注意事项,需要的朋友可以参考下

本文实例讲述了Java中父类和子类之间的转换操作。分享给大家供大家参考，具体如下：

一、父类引用强转成为子类引用

 package learn20180720; public class People { private String name; private Integer age; private Double height; public People(){ this.name = ""; this.age = 0 ; this.height = 0.0; } public People(String name, Integer age, Double height) { super(); this.name = name; this.age = age; this.height = height; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public Double getHeight() { return height; } public void setHeight(Double height) { this.height = height; } public void tellObjectName(People p) { System.err.println(p.name); } public void sayInformation() { System.err.println("我的名字叫做："+this.name+"我的年龄是："+this.age+"我的身高是"+this.height); } }

 package learn20180720; public class Chinese extends People{ private String country; public Chinese(){ super(); country = ""; } public Chinese(String aname,Integer aage,Double aheight) { super(aname,aage,aheight); this.country = "中国"; } public String getCountry() { return country; } public void setCountry(String country) { this.country = country; } public void sayInformation() { // TODO Auto-generated method stub System.err.println("我的名字叫做："+this.getName()+"  我的年龄是："+this.getAge()+"  我的身高是："+this.getHeight()+"  我的国家是："+this.country); } }

 package learn20180720; public class TestPeCh { public static void main(String[] args) { // TODO Auto-generated method stub People p1 = new Chinese(); Chinese c1 = (Chinese)p1; } }

可以看到，p1无法访问子类中的特有的方法（父类引用可以访问子类中重写父类中的方法），但是强转成为子类类型的引用c1之后，c1就可以访问子类中所有的方法啦。

二、父类不可以强转成为子类

 package learn20180720; public class TestPeCh { public static void main(String[] args) { // TODO Auto-generated method stub People p1 = new People(); Chinese c1 = (Chinese)p1; } }