如何解决超类使用Java中构造函数的默认值覆盖子类
我有一个任务,我的超类默认值总是覆盖我在 Test main 方法中传递的值。在调试器中,我看到 productNumber(1234) 和 productTitle("Daughter") 的传递,但随后它被默认值覆盖。有什么想法,我一直在做细微的改变,检查变化,结果还是一样。
产品超类
public abstract class Product {
private int productNumber;
private String productTitle;
//Two constructors required
public Product(){
productNumber = 0;
productTitle = "";
}
public Product(int productNumber,String productTitle) {
this.productNumber = productNumber;
this.productTitle = productTitle;
}
public void setProductNumber(int productNumber) {
this.productNumber = productNumber;
}
public int getProductNumber() {
return productNumber;
}
public void setProductTitle(String productTitle) {
this.productTitle = productTitle;
}
public String getProductTitle() {
return productTitle;
}
//Override toString() required
@Override
public String toString() {
return productNumber + " " + productTitle;
}
// required Product class declares abstract method with this signature: public String getdisplayText()
public abstract String getdisplayText();
//Override equals() required
@Override
public boolean equals(Object object) {
if (object instanceof Product) {
Product product2 = (Product) object;
if (productNumber == (product2.getProductNumber()) &&
productTitle.equals(product2.getProductTitle())){
return true;
}
}
return false;
}
}
音乐子类扩展产品超类
public class Music extends Product {
private String artist;
private String style;
private String medium;
public Music() {
super();
artist = "";
style = "";
medium = "";
}
public Music(int productNumber,String productTitle,String artist,String style,String medium) {
super();
this.artist = artist;
this.style = style;
this.medium = medium;
}
public String getArtist() {
return artist;
}
public void setArtist(String artist) {
this.artist = artist;
}
public String getStyle() {
return style;
}
public void setStyle(String style) {
this.style = style;
}
public String getMedium() {
return medium;
}
public void setMedium(String medium) {
this.medium = medium;
}
@Override
public String getdisplayText() {
return super.toString() + " by " + artist + " " + style + " " + medium;
}
@Override
public boolean equals(Object object){
if (object instanceof Music){
Music m = (Music) object;
if (artist.equals(m.getArtist()) &&
style.equals(m.getStyle()) &&
medium.equals(m.getMedium())){
return true;
}
}
return false;
}
}
打印字符串
public class Test {
public static void main(String[] args) {
// Expected result: 1234 Daughter by Pearljam Alternative online
Music music1 = new Music(1234,"Daughter","Pearljam","Alternative","online");
System.out.println(music1.getdisplayText());
}
}
解决方法
您没有将值从子类传递到父类
你需要在下面做而不是 super() -
super(productNumber,productTitle);
您的代码需要更新:-
public Music(int productNumber,String productTitle,String artist,String style,String medium) {
super(productNumber,productTitle);
this.artist = artist;
this.style = style;
this.medium = medium;
}
,
您需要在 productNumber
构造函数内的 productTitle
调用中将 super(...,...)
和 Music
传递给父类。
你需要调用
on:
push:
branches:
- master
# rest of your workflow jobs
在 Music 构造函数中将参数传递给其父级。
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 dio@foxmail.com 举报,一经查实,本站将立刻删除。