Several ways to read files in java

Java provides a variety of methods for reading files: File class: suitable for basic file operations and reading file contents. FileInputStream: suitable for reading binary files or text files, providing underlying reading operations. FileReader: Specially used to read text files, providing character-by-character reading function. NIO.2: Provides higher-level file operation capabilities, including asynchronous reading and writing. The method chosen should consider factors such as file format, type of read operation, performance requirements, and compatibility.

Several ways to read files in Java

Java provides a variety of mechanisms for reading files. Each mechanism is suitable for different scenarios and requirements. Here are several common ways to read files:

1. File class

The File class provides basic file operation functions, including reading file contents. We can read files through the following code:

<code class="java">File file = new File("path/to/file.txt");
Scanner scanner = new Scanner(file);
while (scanner.hasNextLine()) {
    String line = scanner.nextLine();
    // 处理每一行内容
}
scanner.close();</code>

2. FileInputStream

The FileInputStream class is used to read binary files or text files. It provides a lower-level read operation that can read file contents byte by byte or block by block.

<code class="java">FileInputStream inputStream = new FileInputStream("path/to/file.txt");
byte[] buffer = new byte[1024];
int bytesRead = inputStream.read(buffer);
while (bytesRead != -1) {
    // 处理字节数组
    bytesRead = inputStream.read(buffer);
}
inputStream.close();</code>

3. FileReader

The FileReader class is specially used to read text files. It provides functionality to read file contents character by character.

<code class="java">FileReader fileReader = new FileReader("path/to/file.txt");
BufferedReader bufferedReader = new BufferedReader(fileReader);
String line;
while ((line = bufferedReader.readLine()) != null) {
    // 处理每一行内容
}
bufferedReader.close();</code>

4. NIO.2

NIO.2 (New Input/Output, 2) is a new I/O library introduced in Java 7. It provides higher-level file operation capabilities, including asynchronous reading and writing.

<code class="java">Path path = Paths.get("path/to/file.txt");
Files.readAllLines(path).forEach(line -> {
    // 处理每一行内容
});</code>

Choose the best method

Which method you choose to read a file depends on the following factors:

• File format :Text file or binary file
• Read operation:Sequential read, skip read, or random read
• Performance requirements:Need fast reading or prioritize efficiency
• Compatibility: Java version and target platform

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