import java.util.Comparator; import java.util.Map; public class ValueComparator implements Comparator { Map base; //这里需要将要比较的map集合传进来 public ValueComparator(Map base) { this.base = base; } // Note: this comparator imposes orderings that are inconsistent with equals. //比较的时候，传入的两个参数应该是map的两个key，根据上面传入的要比较的集合base，可以获取到key对应的value，然后按照value进行比较 public int compare(String a, String b) { if (base.get(a) >= base.get(b)) { return -1; } else { return 1; } // returning 0 would merge keys } }