我有一个特许经营类别,其中包含所有者(特许经营所有者名称)、州(特许经营所在州的 2 个字符串)和销售额(当天的总销售额)
public class Franchise implements Comparable <Franchise> {
final String owner;
final String state;
final double sales;
protected Franchise(String owner, String state, double sales ) {
this.owner = owner;
this.state = state;
this.sales = sales;
}
public String toString() {
String str = state + ", " + sales + ", " + owner;
return str;
}
public String getState() {
return state;
}
public double getSales() {
return sales;
}
public int compareTo(Franchise that) {
double thatSales = that.getSales();
if (this.getState().compareTo(that.getState()) < 0)
return -1;
else if (this.getSales() > thatSales)
return -1;
else if (this.getSales() < thatSales)
return 1;
else
return 0;
}
}
比较基于状态升序和销售额降序
import java.util.ArrayList;
import java.util.Collections;
public class FranchiseTester {
public static void main(String[] args) {
ArrayList<Franchise> franchises = new ArrayList<Franchise>();
Franchise a = new Franchise("Andrew Luck", "IN", 1270.5);
Franchise b = new Franchise("Ray Rice", "MD", 1210);
Franchise c = new Franchise("Alfred Morris", "WA", 980.5);
Franchise d = new Franchise("Roddy White", "GA", 670);
Franchise e = new Franchise("Greg Olsen", "SC", 740);
Franchise f = new Franchise("T.Y. Hilton", "IN", 950);
Franchise g = new Franchise("Julio Jones", "GA", 560);
franchises.add(a);
franchises.add(b);
franchises.add(c);
franchises.add(d);
franchises.add(e);
franchises.add(f);
franchises.add(g);
Collections.sort(franchises);
for(int i = 0; i < franchises.size(); i++) {
System.out.print(franchises.get(i) + "\n");
}
}
}
当我比较这些特许经营对象时Collections.sort
他们比较正确,但是当我使用Collections.sort
就像我在这里得到的输出是这样的:
GA,670.0,罗迪·怀特
GA,560.0,胡里奥·琼斯
IN,1270.5,安德鲁·勒克
IN,950.0,T.Y.希尔顿
MD,1210.0,雷·赖斯
SC,740.0,格雷格·奥尔森
西澳州,980.5,阿尔弗雷德·莫里斯
该州的比较仍然正确,但没有正确地按销售额进行比较(特定统计数据的较低销售额应该首先出现)
我认为 .sort 默认情况下比较字符串是状态仍然正确的原因,我的问题是如何实现它以基于销售额进行比较?