Use java's FileWriter.flush() function to write characters in the buffer to a file

Use Java's FileWriter.flush() function to write characters in the buffer to a file

In Java, we often need to write data to a file. In order to improve the efficiency of writing, the operating system usually uses a buffer to temporarily save data, and then writes the data to the file at once. In some cases, we need to write data to the file immediately instead of waiting for the buffer to be full or the program to end. At this time, we can use Java's FileWriter.flush() function to manually write the characters in the buffer to the file.

The FileWriter class is an important class in Java for writing character streams. It provides a series of writing operation methods, including writing characters to the buffer, writing characters in the buffer to a file, etc. Among them, the flush() function is a method used to write characters in the buffer to a file.

Below, we use a simple example to demonstrate how to use the FileWriter.flush() function to write characters in the buffer to a file:

import java.io.FileWriter;
import java.io.IOException;

public class FileWriterDemo {
    public static void main(String[] args) {
        FileWriter writer = null;
        try {
            writer = new FileWriter("test.txt");
            writer.write("Hello, world!");
            writer.flush(); // 手动将缓冲区中的字符写入文件
            System.out.println("数据写入成功！");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (writer != null) {
                try {
                    writer.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

In the above example, we create A file named test.txt and writes the string "Hello, world!" into the file. After calling the writer.write("Hello, world!") method, we call the writer.flush() method to manually write the characters in the buffer to the file. Next, we output a success message.

It should be noted that when using the FileWriter class, we should always maintain good coding habits, that is, close the file stream in time after the operation is completed to release system resources. Taking the above example as an example, we use a finally block to close the file stream after the file writing is completed.

To summarize, the FileWriter.flush() function is a method in Java used to write characters in the buffer to a file. By calling this function manually, we can write the characters in the buffer to the file immediately without waiting for the buffer to be full or the program to end. After writing data to a file, we should always maintain good coding habits, that is, close the file stream in time to release system resources.

Thanks for reading this article, I hope it will help you understand the use of FileWriter in Java!

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