Tri d'un tableau à l'aide du Comparateur

Tout d'abord: le tri d'un tableau, comme Software[], vous devez utiliser java.util.Arrays.sort plutôt que java.util.Collections.sort.

Deuxièmement: depuis votre Comparator est spécifiquement pour les Software le cas, vous devriez écrire new Comparator<Software>() plutôt que de simplement new Comparator(). (Le dernier est en fait mauvais code, même quand elle ne fonctionne pas.)

OriginalL'auteur ruakh

Parce que vous essayez d'utiliser l'objet du tableau d'utilisation ci-dessous:

Arrays.sort(aSoftware);

et votre logiciel de classe implémente implémente Comparable et redéfinir sa méthode compareTo:

@Override
public int compareTo(Software o) {
return this.getSoftwareTitle().compareTo(o.getSoftwareTitle());
}

J'ai fait la correction de votre classe comme ci-dessous:

public class Software implements Comparable<Software>{
//Declare variables
String SoftwareTitle; //SoftwareTitle
int SoftwareStock; //Software totals
double SoftwarePrice; //Software Price
int SoftwareNum; //Software Product ID
double CalculateInventory; //To add inventory
double SoftwareValue; //Software Total value
double value; //Complete inventory total
Software(){
}
Software(String softtitle, int softstock, double softprice, int softitemnum)
{
//Create object constructor
SoftwareTitle = softtitle;
SoftwareStock = softstock;
SoftwarePrice = softprice;
SoftwareNum = softitemnum;
}
//Set Software Title
public void setSoftwareTitle(String softtitle) {
SoftwareTitle = softtitle;
}
//Return Software Title
public String getSoftwareTitle() {
return SoftwareTitle;
}
//Set software inventory
public void setSoftwareStock(int softstock) {
SoftwareStock = softstock;
}
//Return software inventory
public int getSoftwareStock() {
return SoftwareStock;
}
//Set software price
public void setSoftwarePrice(double softprice) {
SoftwarePrice = softprice;
}
//Return software price
public double getSoftwarePrice() {
return SoftwarePrice;
}
//Set item number
public void setSoftwareNum(int softitemnum) {
SoftwareNum = softitemnum;
} //
//return software item number
public int getSoftwareNum() {
return SoftwareNum;
} //
//calculate inventory value
public double Softwarevalue() {
return SoftwarePrice * SoftwareStock;
}
public void setCalculateInventory(double value) {
this.CalculateInventory = value;
}
public double getCalculateInventory() {
double value = 0;
for (int i = 0; i < 3; i++) {
value = Softwarevalue();
}
return value;
}
@Override
public int compareTo(Software o) {
return this.getSoftwareTitle().compareTo(o.getSoftwareTitle());
}
}//end method value

Votre Inventaire class:

public class Inventory {
public static void main(String args[])
{
//Start array of software titles
Software[] aSoftware = new Software[4];
aSoftware[0] = new Software("Command and Conquer ", 6, 29.99, 10122);
aSoftware[1] = new Software("Alice in Wonderland", 1, 10.99, 10233);
aSoftware[2] = new Software("Doom", 1, 10.99, 10344);
aSoftware[3] = new Software("Walking Dead", 6, 9.99, 10455);
//Set currency format
DecimalFormat money = new DecimalFormat("$0.00");
Arrays.sort(aSoftware);
//Display software title, number of units, cost, item number and total
//inventory
for (int i = 0; i < aSoftware.length; i++) {
System.out.println("Software Title is "
+ aSoftware[i].getSoftwareTitle());
System.out.println("The number of units in stock is "
+ aSoftware[i].getSoftwareStock());
System.out.println("The price of the Software Title is "
+ (money.format(aSoftware[i].getSoftwarePrice())));
System.out.println("The item number is "
+ aSoftware[i].getSoftwareNum());
System.out.println("The value of the Software Inventory is "
+ (money.format(aSoftware[i].Softwarevalue())));
System.out.println();
}
//output total inventory value
double total = 0.0;
for (int i = 0; i < 3; i++) {
total += aSoftware[i].getCalculateInventory();
}
System.out.printf("Total Value of Software Inventory is: \t$%.2f\n",
total);
//end output total inventory value
}
}

Ci-dessous est la sortie finale dans l'ordre de tri:

Software Title is Alice in Wonderland
The number of units in stock is 1
The price of the Software Title is $10.99
The item number is 10233
The value of the Software Inventory is $10.99
Software Title is Command and Conquer 
The number of units in stock is 6
The price of the Software Title is $29.99
The item number is 10122
The value of the Software Inventory is $179.94
Software Title is Doom
The number of units in stock is 1
The price of the Software Title is $10.99
The item number is 10344
The value of the Software Inventory is $10.99
Software Title is Walking Dead
The number of units in stock is 6
The price of the Software Title is $9.99
The item number is 10455
The value of the Software Inventory is $59.94
Total Value of Software Inventory is:   $201.92

OriginalL'auteur user3468976