java - 如何在Java中正确使用Comparable来处理字符串？

Question

我有以下界面:

public interface Generator <T> {
public T next ();}

以及具有多个方法和字段的类。我将按顺序编写代码，以便您能够理解我的问题。 类(class):

public class Example implements Comparable <Example>{}

此类具有以下字段:

private String name;
private static int count;
private int ID = count ++;
private static char [] chars = "qwertyuiopasdfghjklzxcvbnm".toCharArray();

构造函数:

public Example (String name){
    this.name = name;
}

返回类信息的方法:

public String toString (){
    return "ID #" + ID + ", name: " + name;
}

生成新类的方法:

public static Generator <Example> generator (){
    return new Generator <Example> (){
        public Example next() {
            Random rand = new Random ();
            StringBuilder str = new StringBuilder ();
            for (int i=0; i!=10; i++)
                str.append(chars[rand.nextInt(chars.length)]);
            return new Example (str.toString());
        }
    };
}

还有这个我无法理解的难以理解的方法:

    public int compareTo(Example o) {
    return (this.name < o.name ? -1 : (this.name == o.name ? 0 : 1)); // It does not works... :(
}

生成数组的通用方法:

    public static <T> List <T> array (List <T> list, Generator <T> gen, int size){
    for (int i=0; i!=size; i++){
        list.add(gen.next());
    } return list;
}

当我尝试比较排序数组时主要方法:

public static void main (String [] args){
    List <Example> list = new ArrayList <Example> (); // Created the array;
    array (list, generator(), 10); // Filled the array;
    Collections.sort(list); // Doesn't work :(

}

我对我的英语感到抱歉。英语不是我的母语。 谢谢:)

Answer 1

return (this.name < o.name ? -1 : (this.name == o.name ? 0 : 1)); // It does not works... :(

在你的compareTo()中您正在将 String 与 < 进行比较的实现无效的运算符。你可以这样做

return this.name.compareTo(o.name); // for natural string comparison