我正在尝试模拟相册库。但我还可以按照作者姓名的字母顺序组织图书馆的内容。对于如何按字母顺序组织对象数组的内容有任何帮助吗？
我创建了一个名为Album 的类，我用它来创建我的对象
public class Album {
private String author;
private String name;
private String year;
public Album(String a, String n, String y) { // constructor
author = a;
name = n;
year = y;
}
public String toString()
{
return author +","+ name + "," + year;
}
}
Collection类用于将对象存储到数组中
public class AlbumCollection {
public Album collection[]= new Album[10];
private int numAlbums = 0;
public void add (Album a){
if (numAlbums >= collection.length){
Album newcollection[]= new Album [collection.length * 2];
for (int n = 0; n < numAlbums; n ++){
newcollection[n] = collection[n];
}
newcollection = collection;
}
collection[numAlbums] = a;
numAlbums = numAlbums + 1;
}
public String toString()
{
String details = "";
for ( int p = 0; p < collection.length ; p ++)
{
details = details + collection[p] + "\n" ;
}
details += "\n";
return details;
}
}
这是我用来创建专辑对象的类
public class TestCollection {
public static void main(String[] args) {
AlbumCollection c = new AlbumCollection();
c.add( new Album("DaftPunk","Discovery","2001"));
c.add( new Album ("Pink Floid","The Dark Side Of The Moon","1973"));
c.add( new Album( "The Clash", "London Calling", "1979"));
System.out.print(c);
}
}
最佳答案
我必须更改compareTo 方法以按作者排序。
public class Album {
private String author;
private String name;
private String year;
public Album(String a, String n, String y) { // constructor
author = a;
name = n;
year = y;
}
public String toString()
{
return author +","+ name + "," + year;
}
public int compareTo(Album a) {
// usually toString should not be used,
// instead one of the attributes or more in a comparator chain
return author.compareTo(a.author);
}
} 我添加了方法 sort 来对数组元素进行排序:
public class Collection {
public Album collection[]= new Album[10];
private int numAlbums = 0;
public void Add (Album a){
if (numAlbums >= collection.length){
Album newcollection[]= new Album [collection.length * 2];
for (int n = 0; n < numAlbums; n ++){
newcollection[n] = collection[n];
}
newcollection = collection;
}
collection[numAlbums] = a;
numAlbums = numAlbums + 1;
}
public String toString()
{
String details = "";
for ( int p = 0; p < numAlbums ; p ++)
{
details = details + collection[p] + "\n" ;
}
details += "\n";
return details;
}
public void sort(){
for(int i=0;i<numAlbums;i++){
for(int j=i;j<numAlbums-1;j++){
if(collection[j].compareTo(collection[j+1])>0){
Album tmp =collection[j];
collection[j]=collection[j+1];
collection[j+1]=tmp;
}
}
}
}
}
如果您存储作者数量，则不能使用数组的长度，因为您将打印空值
public static void main(String[] args) {
Collection c = new Collection();
c.Add( new Album("DaftPunk","Discovery","2001"));
c.Add( new Album ("Pink Floid","The Dark Side Of The Moon","1973"));
c.Add( new Album( "The Clash", "London Calling", "1979"));
c.sort();
System.out.print(c);
}
关于java - 如何在 Java 中按字母顺序组织对象数组，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/52918180/