How do I create and write a file? Recommended | Java Debug Notes

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Question: How do I join two arrays in Java

What is the easiest way to create and write (text) files in Java?

Answer:

$\color{purple} a lot of knowledge points, really need to write out just can master!! {~}$

Note that each of the following code examples may throw an IOException. The try/catch/finally block is omitted for simplicity. See this tutorial for information about exception handling.

Note that each code example below overwrites this file (if it already exists)

Create a text file:

PrintWriter writer = new PrintWriter("the-file-name.txt", "UTF-8");
writer.println("The first line");
writer.println("The second line");
writer.close();
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Create a binary file:

byte data[] = ...
FileOutputStream out = new FileOutputStream("the-file-name");
out.write(data);
out.close();
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Java 7+ users can use the Files class to write Files:

Create a text file:

List<String> lines = Arrays.asList("The first line", "The second line");
Path file = Paths.get("the-file-name.txt");
Files.write(file, lines, StandardCharsets.UTF_8);
//Files.write(file, lines, StandardCharsets.UTF_8, StandardOpenOption.APPEND);
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Create a binary file:

byte data[] = ...
Path file = Paths.get("the-file-name");
Files.write(file, data);
//Files.write(file, data, StandardOpenOption.APPEND);
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In Java 7 and later:

try (Writer writer = new BufferedWriter(new OutputStreamWriter(
              new FileOutputStream("filename.txt"), "utf-8"))) {
   writer.write("something");
}
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The article translated from kgs4h5t57thfb6iyuz6dqtun5y ac4c6men2g7xr2a – stackoverflow – com. Translate. Goog/questions / 2…

The author suggests: the high score answer here is simply a simple implementation

As you can see, The Performance of FileChannel is relatively high. Briefly, take rocketMQ, which is a popular file system for storing data, producing and consuming data as directly manipulated files, It involves page caching, FileChannel, and FileChannel reading a page of 4KB at a time, thanks to ByteBuffer buffers and MMAP memory mapping

RokcetMQ has also been tuned for better performance

• Pre-allocated MappedFile
• Mlock system call
• File preheating
• Read and write sequentially

I’m just doing a piece here, everybody come on!

$\color{red} Welcome to my column StackOverFlow, I will filter the quality of the interview test!! {~}$

$\color{red} has the latest, elegant implementation, and I will also write my opinion on this question at the end of the article {~}$

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