//构造器 public DbNode() { data = default(T); next = null; }
//构造器 public DbNode(DbNode <T> p) { next = p; }
//构造器 public DbNode(T val) { data = val; next = null; }
private DbNode <T> next; //后继引用域 public DbNode(T val, DbNode <T> p) //构造器 { //构造器 data = val; next = p; }