In this quick tutorial, we’re going to write the contents of a Reader to a File using plain Java, then Guava and finally the Apache Commons IO library.
在这个快速教程中，我们将使用普通Java，然后是Guava，最后是Apache Commons IO库来将Reader的内容写入文件。
This article is part of the “Java – Back to Basic” series here on Baeldung.
本文是Baeldung网站上“Java – Back to Basic “系列的一部分。
1. With Java
1.使用Java
Let’s start with the simple Java solution:
让我们从简单的Java解决方案开始。
@Test
public void givenUsingPlainJava_whenWritingReaderContentsToFile_thenCorrect()
throws IOException {
Reader initialReader = new StringReader("Some text");
int intValueOfChar;
StringBuilder buffer = new StringBuilder();
while ((intValueOfChar = initialReader.read()) != -1) {
buffer.append((char) intValueOfChar);
}
initialReader.close();
File targetFile = new File("src/test/resources/targetFile.txt");
targetFile.createNewFile();
Writer targetFileWriter = new FileWriter(targetFile);
targetFileWriter.write(buffer.toString());
targetFileWriter.close();
}First – we’re reading the contents of the Reader into a String; then we’re simply writing the String to File.
首先–我们把阅读器的内容读成一个字符串；然后我们简单地把这个字符串写到File。
2. With Guava
2.有番石榴
The Guava solution is simpler – we now have the API to deal with writing the reader to file:
Guava的解决方案更简单–我们现在有API来处理将阅读器写入文件的问题。
@Test
public void givenUsingGuava_whenWritingReaderContentsToFile_thenCorrect()
throws IOException {
Reader initialReader = new StringReader("Some text");
File targetFile = new File("src/test/resources/targetFile.txt");
com.google.common.io.Files.touch(targetFile);
CharSink charSink = com.google.common.io.Files.
asCharSink(targetFile, Charset.defaultCharset(), FileWriteMode.APPEND);
charSink.writeFrom(initialReader);
initialReader.close();
}3. With Apache Commons IO
3.使用Apache Commons IO
And finally, the Commons IO solution – also using higher level APIs to read data from the Reader and write that data to file:
最后是Commons IO解决方案–也是使用更高级别的API从Reader读取数据，并将该数据写入文件。
@Test
public void givenUsingCommonsIO_whenWritingReaderContentsToFile_thenCorrect()
throws IOException {
Reader initialReader = new CharSequenceReader("CharSequenceReader extends Reader");
File targetFile = new File("src/test/resources/targetFile.txt");
FileUtils.touch(targetFile);
byte[] buffer = IOUtils.toByteArray(initialReader);
FileUtils.writeByteArrayToFile(targetFile, buffer);
initialReader.close();
}And there we have it – 3 simple solutions for writing the contents of a Reader to File. Make sure to check out the sample over on GitHub.