大约有 46,000 项符合查询结果（耗时：0.0386秒） [XML]
When do you use map vs flatMap in RxJava?
...onError handler for you.
Observable.from(jsonFile).map(new Func1<File, String>() {
@Override public String call(File file) {
try {
return new Gson().toJson(new FileReader(file), Object.class);
} catch (FileNotFoundException e) {
// this exception is...
Computed / calculated / virtual / derived columns in PostgreSQL
...l, but makes makes life a bit easier).
Suppose my computation is md5(some_string_field), then I create the index as:
CREATE INDEX some_string_field_md5_index ON some_table(MD5(some_string_field));
Now, any queries that act on MD5(some_string_field) will use the index rather than computing it fr...
Is there any kind of hash code function in JavaScript?
...
JavaScript objects can only use strings as keys (anything else is converted to a string).
You could, alternatively, maintain an array which indexes the objects in question, and use its index string as a reference to the object. Something like this:
var Ob...
How can I ssh directly to a particular directory?
... specific (or any) hosts with the normal ssh command without having to use extra command line arguments, you can set the RequestTTY and RemoteCommand options in your ssh config file.
For example, I'd like to type only this command:
ssh qaapps18
but want it to always behave like this command:
ss...
How can I use inverse or negative wildcards when pattern matching in a unix/linux shell?
...s) <(ls *Music*)
comm is preferable over diff because it doesn't have extra cruft.
This returns all elements of set 1, ls, that are not also in set 2, ls *Music*. This requires both sets to be in sorted order to work properly. No problem for ls and glob expansion, but if you're using something...
When use getOne and findOne methods Spring Data JPA
...));
}
LockModeType type = metadata.getLockModeType();
Map<String, Object> hints = getQueryHints().withFetchGraphs(em).asMap();
return Optional.ofNullable(type == null ? em.find(domainType, id, hints) : em.find(domainType, id, type, hints));
}
And here em.find() is an Entit...
How can I make a multipart/form-data POST request using Java?
...ost = new HttpPost(url);
FileBody bin = new FileBody(new File(fileName));
StringBody comment = new StringBody("Filename: " + fileName);
MultipartEntity reqEntity = new MultipartEntity();
reqEntity.addPart("bin", bin);
reqEntity.addPart("comment", comment);
httppost.setEntity(reqEntity);
HttpRespo...
Why does javascript replace only first instance when using replace? [duplicate]
...C#/.NET class library (and most other sensible languages), when you pass a String in as the string-to-match argument to the string.replace method, it doesn't do a string replace. It converts the string to a RegExp and does a regex substitution. As Gumbo explains, a regex substitution requires the g...
Inline SVG in CSS
... and if it doesn't work (it might complain about invalid characters in the string), you can simply use https://www.base64encode.org/.
Example to set a div background:
var mySVG = "<svg xmlns='http://www.w3.org/2000/svg' width='10' height='10'><linearGradient id='gradient'><stop ...
Android Layout with ListView and Buttons
..._height="wrap_content" android:id="@+id/testbutton"
android:text="@string/hello" android:layout_alignParentBottom="true" />
<ListView android:layout_width="fill_parent"
android:layout_height="fill_parent" android:id="@+id/list"
android:layout_alignParentTop="true" ...