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