相关疑难解决方法(0)

在尝试根据元素字符串长度对数组进行排序时,我遇到了编译错误.我有一套开始,

Set<String> arraycat = new HashSet<String>();
//add contents to arraycat
String[] array = arraycat.toArray(new String[0]);
//array looks like this now:
//array=[cat,cataaaa,cataa,cata,cataaa]

我理想的是要排序到

array=[cat,cata,cataa,cataaa,cataaaa]

所以我有一个类型的比较器

class comp implements Comparator {

    public int compare(String o1, String o2) {
        if (o1.length() > o2.length()) {
            return 1;
        } else if (o1.length() < o2.length()) {
            return -1;
        } else {
            return 0;
        }
    }
}

然后我打电话给上课

Collections.sort(array, new comp());

但是,它抛出了两个编译错误:

comp is not abstract and does not override abstract method   compare(java.lang.Object,java.lang.Object) in java.util.Comparator
class comp …