本帖最后由 黄小贝 于 2012-10-3 02:29 编辑
目测你的Student_Human没有实现Comparable接口,TreeSet的add方法调用了TreeMap的put方法
如果比较器为null ,则插入的元素需要实现Comparable 接口,所以~你要么传一个比较器进去,要么实现Comparable 接口~- public V put(K key, V value) {
- Entry<K,V> t = root;
- if (t == null) {
- // TBD:
- // 5045147: (coll) Adding null to an empty TreeSet should
- // throw NullPointerException
- //
- // compare(key, key); // type check
- root = new Entry<K,V>(key, value, null);
- size = 1;
- modCount++;
- return null;
- }
- int cmp;
- Entry<K,V> parent;
- // split comparator and comparable paths
- Comparator<? super K> cpr = comparator;
- if (cpr != null) {
- do {
- parent = t;
- cmp = cpr.compare(key, t.key);
- if (cmp < 0)
- t = t.left;
- else if (cmp > 0)
- t = t.right;
- else
- return t.setValue(value);
- } while (t != null);
- }
- else {
- if (key == null)
- throw new NullPointerException();
- Comparable<? super K> k = (Comparable<? super K>) key;
- do {
- parent = t;
- cmp = k.compareTo(t.key);
- if (cmp < 0)
- t = t.left;
- else if (cmp > 0)
- t = t.right;
- else
- return t.setValue(value);
- } while (t != null);
- }
- Entry<K,V> e = new Entry<K,V>(key, value, parent);
- if (cmp < 0)
- parent.left = e;
- else
- parent.right = e;
- fixAfterInsertion(e);
- size++;
- modCount++;
- return null;
- }
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