我正在尝试使用带有无符号长比较器的树形图。但是，树形图的 put 似乎正在删除整体。没有比较器，它工作得很好，但我似乎无法弄清楚比较器有什么问题。下面的示例代码：
公共类主要{
public static void main(String args[]) {
class UnsignComparator implements Comparator<Long> {
@Override
public int compare(Long o1, Long o2) {
if (isLessThanUnsigned(o1, o2)) {
return -1;
} else if (o1.equals(o2)) {
return 0;
} else {
return -1;
}
}
}
TreeMap<Long, String> consistent = new TreeMap<Long, String>(
new UnsignComparator());
System.out.println("Treemap with comparator");
consistent.put(1L, "a");
System.out.println("1L: " + consistent.containsKey(1L));
consistent.put(2L, "b");
System.out.println("1L: " + consistent.containsKey(1L));
System.out.println("2L: " + consistent.containsKey(2L));
consistent.put(3L, "c");
System.out.println("1L: " + consistent.containsKey(1L));
System.out.println("2L: " + consistent.containsKey(2L));
System.out.println("3L: " + consistent.containsKey(3L));
System.out.println("Treemap with comparator keyset");
for (long keys : consistent.keySet()) {
System.out.println(keys);
}
System.out.println("Treemap without comparator");
TreeMap<Long, String> treemap = new TreeMap<Long, String>();
treemap.put(1L, "a");
System.out.println("1L: " + treemap.containsKey(1L));
treemap.put(2L, "b");
System.out.println("1L: " + treemap.containsKey(1L));
System.out.println("2L: " + treemap.containsKey(2L));
treemap.put(3L, "c");
System.out.println("1L: " + treemap.containsKey(1L));
System.out.println("2L: " + treemap.containsKey(2L));
System.out.println("3L: " + treemap.containsKey(3L));
}
//from http://www.javamex.com/java_equivalents/unsigned_arithmetic.shtml
private static boolean isLessThanUnsigned(long n1, long n2) {
return (n1 < n2) ^ ((n1 < 0) != (n2 < 0));
}
}
结果如下：
Treemap with comparator
1L: true
1L: true
2L: true
1L: false //expected true
2L: true
3L: true
Treemap with comparator keyset
3
2
1
Treemap without comparator
1L: true
1L: true
2L: true
1L: true
2L: true
3L: true