Scala：在一个语句中将字符串写入文件
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Scala: write string to file in one statement
提问by smartnut007
For reading files in Scala, there is
对于在 Scala 中读取文件，有
Source.fromFile("file.txt").mkString
Is there an equivalent and concise way to write a string to file?
是否有等效且简洁的方法将字符串写入文件？
Most languages support something like that. My favorite is Groovy:
大多数语言都支持类似的东西。我最喜欢的是 Groovy：
def f = new File("file.txt")
// Read
def s = f.text
// Write
f.text = "file contents"
I'd like to use the code for programs ranging from a single line to a short page of code. Having to use your own library doesn't make sense here. I expect a modern language to let me write something to a file conveniently.
我想将代码用于从一行到一小页代码的程序。必须使用自己的库在这里没有意义。我希望有一种现代语言能让我方便地向文件中写入内容。
There are posts similar to this, but they don't answer my exact question or are focused on older Scala versions.
有与此类似的帖子，但它们没有回答我的确切问题或专注于较旧的 Scala 版本。
For example:
例如：
采纳答案by LRLucena
A concise one line:
简洁的一行：
import java.io.PrintWriter
new PrintWriter("filename") { write("file contents"); close }
回答by Vladimir Matveev
It is strange that no one had suggested NIO.2 operations (available since Java 7):
奇怪的是，没有人建议过 NIO.2 操作（自 Java 7 开始可用）：
import java.nio.file.{Paths, Files}
import java.nio.charset.StandardCharsets
Files.write(Paths.get("file.txt"), "file contents".getBytes(StandardCharsets.UTF_8))
I think this is by far the simplest and easiest and most idiomatic way, and it does not need any dependencies sans Java itself.
我认为这是迄今为止最简单、最简单和最惯用的方法，它不需要任何依赖项，没有 Java 本身。
回答by Garrett Hall
Here is a concise one-liner using reflect.io.file, this works with Scala 2.12:
这是使用reflect.io.file的简洁单行，这适用于Scala 2.12：
reflect.io.File("filename").writeAll("hello world")
Alternatively, if you want to use the Java libraries you can do this hack:
或者，如果您想使用 Java 库，您可以执行以下操作：
Some(new PrintWriter("filename")).foreach{p => p.write("hello world"); p.close}
回答by paradigmatic
If you like Groovy syntax, you can use the Pimp-My-Librarydesign pattern to bring it to Scala:
如果您喜欢 Groovy 语法，可以使用Pimp-My-Library设计模式将其引入 Scala：
import java.io._
import scala.io._
class RichFile( file: File ) {
def text = Source.fromFile( file )(Codec.UTF8).mkString
def text_=( s: String ) {
val out = new PrintWriter( file , "UTF-8")
try{ out.print( s ) }
finally{ out.close }
}
}
object RichFile {
implicit def enrichFile( file: File ) = new RichFile( file )
}
It will work as expected:
它将按预期工作：
scala> import RichFile.enrichFile
import RichFile.enrichFile
scala> val f = new File("/tmp/example.txt")
f: java.io.File = /tmp/example.txt
scala> f.text = "hello world"
scala> f.text
res1: String =
"hello world
回答by xiefei
import sys.process._
"echo hello world" #> new java.io.File("/tmp/example.txt") !
回答by pathikrit
A micro library I wrote: https://github.com/pathikrit/better-files
我写的一个微库：https: //github.com/pathikrit/better-files
file.write("Hi!")
or
或者
file << "Hi!"
回答by RyuuGan
You can easily use Apache File Utils. Look at function writeStringToFile. We use this library in our projects.
您可以轻松使用Apache File Utils。看功能writeStringToFile。我们在我们的项目中使用这个库。
回答by Luigi Sgro
This is concise enough, I guess:
这足够简洁，我想：
scala> import java.io._
import java.io._
scala> val w = new BufferedWriter(new FileWriter("output.txt"))
w: java.io.BufferedWriter = java.io.BufferedWriter@44ba4f
scala> w.write("Alice\r\nBob\r\nCharlie\r\n")
scala> w.close()
回答by Dibbeke
One also has this format, which is both concise and the underlying library is beautifully written (see the source code):
一个也有这种格式，既简洁又底层库写得很漂亮（见源码）：
import scalax.io.Codec
import scalax.io.JavaConverters._
implicit val codec = Codec.UTF8
new java.io.File("hi-file.txt").asOutput.write("I'm a hi file! ... Really!")
回答by stefan.schwetschke
You can do this with a mix of Java and Scala libraries. You will have full control over the character encoding. But unfortunately, the file handles will not be closed properly.
您可以混合使用 Java 和 Scala 库来做到这一点。您将完全控制字符编码。但不幸的是，文件句柄将无法正确关闭。
scala> import java.io.ByteArrayInputStream
import java.io.ByteArrayInputStream
scala> import java.io.FileOutputStream
import java.io.FileOutputStream
scala> BasicIO.transferFully(new ByteArrayInputStream("test".getBytes("UTF-8")), new FileOutputStream("test.txt"))
