大约有 44,000 项符合查询结果（耗时：0.0620秒） [XML]
How to view the SQL queries issued by JPA?
...tabaseQuery();
databaseQuery.prepareCall(session, new DatabaseRecord());
String sqlString = databaseQuery.getSQLString();
This SQL will contain ? for parameters. To get the SQL translated with the arguments you need a DatabaseRecord with the parameter values.
DatabaseRecord recordWithValues= ne...
Why doesn't the example compile, aka how does (co-, contra-, and in-) variance work?
...w Integer[1];
arr[0] = "Hello, there!";
We just assigned a value of type String to an array of type Integer[]. For reasons which should be obvious, this is bad news. Java's type system actually allows this at compile time. The JVM will "helpfully" throw an ArrayStoreException at runtime. Scala...
Is it better to use Enumerable.Empty() as opposed to new List() to initialize an IEnumerable
...ing it to a new list in the constructor:
public class Person
{
public string Name { get; set; }
public IList<Role> Roles { get; private set; }
public Person()
{
Roles = new List<Role>();
}
}
If you really really want to have the public setter, leave Roles ...
Fully custom validation error message with Rails
..._name method on the model class. The method is passed the column name as a string and returns the string to use in validation messages.
class User < ActiveRecord::Base
HUMANIZED_ATTRIBUTES = {
:email => "E-mail address"
}
def self.human_attribute_name(attr)
HUMANIZED_ATTRIBUTE...
Weird Integer boxing in Java
...
public class Scratch
{
public static void main(String[] args)
{
Integer a = 1000, b = 1000; //1
System.out.println(a == b);
Integer c = 100, d = 100; //2
System.out.println(c == d);
}
}
Output:
false
true
Yep the first output...
How do you check if a JavaScript Object is a DOM Object?
... && typeof o.nodeType === "number" && typeof o.nodeName==="string"
);
}
//Returns true if it is a DOM element
function isElement(o){
return (
typeof HTMLElement === "object" ? o instanceof HTMLElement : //DOM2
o && typeof o === "object" && o !== null ...
How do I return early from a rake task?
... an exit code of 1) you'll want to use abort, which also takes an optional string param that will get outputted on exit:
task :check do
# If any of your checks fail, you can exit early like this.
abort( "One of the checks has failed!" ) if check_failed?
end
On the command line:
$ rake che...
What's the difference between encoding and charset?
...ere are multiple encodings for Unicode. An encoding is a way of mapping a string of characters to a string of bytes. Examples of Unicode encodings include UTF-8, UTF-16 BE, and UTF-16 LE . Each of these has advantages for particular applications or machine architectures.
...
How does the const constructor actually work?
...3
var baz1 = const Baz(const Foo(1, 1), "hello"); // $Baz$Foo$int$1$int$1$String$hello
var baz2 = const Baz(const Foo(1, 1), "hello"); // $Baz$Foo$int$1$int$1$String$hello
Constants are not recreated each time. They are canonicalized at compile time and stored in special lookup tables (where they...
How can I search for a commit message on GitHub?
...me point mid-2013. To achieve this locally, you can do:
git log -g --grep=STRING
(Use the -g flag if you want to search other branches and dangling commits.)
-g, --walk-reflogs
Instead of walking the commit ancestry chain, walk reflog entries from
the most recent one to older ones.
...