Confusion for Java beginners: Precautions for IO stream operations

In IO stream operations, Java beginners need to pay attention to the following: the stream should be closed after reading or writing to release resources. Exception handling is very important for IO operations. Choose the correct stream type (character stream or byte stream). The following practical example shows how to read and write files: Reading a file: Use BufferedReader and FileReader to read the contents line by line from "file.txt". Writing to a file: Use BufferedWriter and FileWriter to write "Hello, world!" to "file.txt".

Things Java beginners need to pay attention to in IO stream operations

Introduction

For Java beginners, IO stream operations can be confusing, especially when file input and output are involved. This article aims to clarify these confusions by providing some considerations and practical examples.

Notes

• Close the stream: After a read or write operation is completed, always close the stream to release system resources.
• Exception handling: IO operations may throw exceptions, so proper exception handling is crucial.
• Character stream and byte stream: Java provides two types of streams: character stream (Reader/Writer) and byte stream (InputStream/OutputStream). Choosing the appropriate stream type is very important for correct processing of data.

Practical case

Read file

try (BufferedReader reader = new BufferedReader(new FileReader("file.txt"))) {
    String line;
    while ((line = reader.readLine()) != null) {
        // 处理每一行
    }
} catch (IOException e) {
    e.printStackTrace();
}

Write file

try (BufferedWriter writer = new BufferedWriter(new FileWriter("file.txt"))) {
    writer.write("Hello, world!");
} catch (IOException e) {
    e.printStackTrace();
}

Note: In these cases, we use try-with-resources statements to ensure that the stream is closed properly at the end of the statement block.

Other Tips

• Using wrapper classes such as Scanner and PrintWriter can simplify IO operations.
• Consider using buffered streams to improve performance.
• Understand the stream hierarchy (FileInputStream -> BufferedInputStream -> DataInputStream) and stream modifiers (PushbackInputStream, FilterInputStream).

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