Java language file operation skills

The Java language is a very popular programming language with a wide range of applications, especially in file operations. In this article, we will introduce several Java language file operation techniques to help you better process files.

1. Reading files

The Java language provides a variety of ways to read files. The most common way is to use the BufferedReader class. The BufferedReader class provides the readLine() method, which can read the file content line by line and return a string. In addition, Java can also use the Scanner class to read file contents.

For example, the following code uses BufferedReader to read the file content:

try {
    BufferedReader br = new BufferedReader(new FileReader("file.txt"));
    String line = br.readLine();
    while (line != null) {
        System.out.println(line);
        line = br.readLine();
    }
    br.close();
} catch (IOException e) {
    e.printStackTrace();
}

2. Writing of files

The Java language also provides a variety of ways to write Import the file. The most common way is to use the FileWriter class. The FileWriter class only needs to specify the file path and file name to be written, and provides a method write() to write a string, so that the content can be written to the file.

For example, the following code uses a FileWriter to write content to a file:

try {
    FileWriter fw = new FileWriter("file.txt");
    fw.write("Hello World
");
    fw.close();
} catch (IOException e) {
    e.printStackTrace();
}

3. Copying of files

In Java, file copying can be done using FileInputStream and FileOutputStream class. The FileInputStream class can read a data stream, and the FileOutputStream class can write a data stream to a file.

For example, the following code copies one file to another:

try {
    FileInputStream in = new FileInputStream("file1.txt");
    FileOutputStream out = new FileOutputStream("file2.txt");
    byte[] buffer = new byte[1024];
    int len;
    while ((len = in.read(buffer)) > 0) {
        out.write(buffer, 0, len);
    }
    in.close();
    out.close();
} catch (IOException e) {
    e.printStackTrace();
}

4. Renaming and deletion of files

Can be used in Java language renameTo() method to rename files. This method requires a new file name of type File as parameter. In addition, you can also use the delete() method to delete files.

For example, the following code renames the file to newFile.txt:

File oldFile = new File("file.txt");
File newFile = new File("newFile.txt");
if (oldFile.renameTo(newFile)) {
    System.out.println("文件已重命名。");
} else {
    System.out.println("重命名操作失败。");
}

For example, the following code deletes the file:

File file = new File("file.txt");
if (file.delete()) {
    System.out.println("文件已被删除。");
} else {
    System.out.println("删除操作失败。");
}

The above are several Java language file operation techniques introduce. These tips can help you handle files better and improve file processing efficiency.

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