大约有 15,210 项符合查询结果（耗时：0.0678秒） [XML]
What is hashCode used for? Is it unique?
...ingerprint. We can use this finger print to identify people of interest.
Read below for more details:
Think of a Hashcode as us trying to To Uniquely Identify Someone
I am a detective, on the look out for a criminal. Let us call him Mr Cruel. (He was a notorious murderer when I was a kid -- he b...
What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
...ence', 1)
INSERT INTO post_comment (post_id, review, id)
VALUES (2, 'Must-read for Java developers', 2)
INSERT INTO post_comment (post_id, review, id)
VALUES (3, 'Five Stars', 3)
INSERT INTO post_comment (post_id, review, id)
VALUES (4, 'A great reference book', 4)
N+1 query problem with plain ...
Why is require_once so bad to use?
Everything I read about better PHP coding practices keeps saying don't use require_once because of speed.
14 Answers
...
Abusing the algebra of algebraic data types - why does this work?
...nked to a paper about that in my answer but I could swear I remember first reading about it on your blog.
– C. A. McCann
Feb 8 '12 at 20:00
1
...
Various ways to remove local Git changes
...It all depends on exactly what you are trying to undo/revert. Start out by reading the post in Ube's link. But to attempt an answer:
Hard reset
git reset --hard [HEAD]
completely remove all staged and unstaged changes to tracked files.
I find myself often using hard resetting, when I'm like "ju...
How do servlets work? Instantiation, sessions, shared variables and multithreading
...tore their scoped beans as an attribute of its closest matching scope.
Thread Safety
That said, your major concern is possibly thread safety. You should now know that servlets and filters are shared among all requests. That's the nice thing about Java, it's multithreaded and different threads (re...
public friend swap member function
... and others mistakenly thought would be the case. If you were bit by this, read here.
In short: the member function is just noise, the specialization is ugly and incomplete, but the friend function is complete and works. And when you swap, either use boost::swap or an unqualified swap with std::s...
What do
... not find implicit value for parameter evidence: =:=[Int,String]
You can read that error as "could not find evidence that Int == String"... that's as it should be! getStringLength is imposing further restrictions on the type of A than what Foo in general requires; namely, you can only invoke getSt...
Creating a singleton in Python
...h essentially recreates C-style structs in Python using metaclasses. The thread What are some (concrete) use-cases for metaclasses? also provides some examples, they generally seem to be related to declarative programming, especially as used in ORMs.
In this situation, if you use your Method #2, and...
Servlet returns “HTTP Status 404 The requested resource (/servlet) is not available”
... name, case sensitive!), and the servlet hasn't failed its initialization (read server logs for any deploy/servlet success/fail messages and the actual context path and servlet mapping), then a servlet with URL pattern of /servlet is available at http://localhost:8080/contextname/servlet.
You can ...