Interpretation of InputStreamReader in Java

Java Convert StreamInputStreamReader

1. Introduction to InputStreamReader

InputStreamReader is a class in the package that inherits the class.

Its main function is to convert the byte input stream into a character input stream.

When performing file read and write operations, if you encounter a different encoding format, you can use InputStreamReader to process it.

2. InputStreamReader construction method

InputStreamReader provides the following two constructors:

(1) InputStreamReader(InputStream in) Create an InputStreamReader instance using the default character set.
(2) InputStreamReader(InputStream in, Charset cs) Create an InputStreamReader instance using the specified character set.

3. Common methods of InputStreamReader

Here are some common methods of InputStreamReader:

(1) int read() reads a character and returns the read character. If the end of the file is reached, it returns -1.
(2) int read(char[] cbuf, int offset, int length) Read characters into part of the array, returns the number of characters read, and if the end of the file is reached, return -1.
(3) boolean ready() determines whether the InputStreamReader is ready to read data.
(4) void close() close InputStreamReader and release relevant resources.

4. Code examples and running results

Here is a simple example that demonstrates how to read a text file using InputStreamReader:

import ;
import ;
import ;
public class InputStreamReaderExample {
    public static void main(String[] args) {
        try {
            // Create FileInputStream instance            FileInputStream fis = new FileInputStream("");
            
            // Create an InputStreamReader instance, using the default character set            InputStreamReader isr = new InputStreamReader(fis);
            
            // Read file content            int data;
            while ((data = ()) != -1) {
                ((char) data);
            }
            
            // Close the stream            ();
            ();
        } catch (IOException e) {
            ();
        }
    }
}

Assume that the file content is as follows:

Hello, World!
Hello World!

Run the above code and the output result is as follows:

Hello, World!
Hello World!

Next, we read the file using the specified character set:

import ;
import ;
import ;
import ;
public class InputStreamReaderExample2 {
    public static void main(String[] args) {
        try {
            // Create FileInputStream instance            FileInputStream fis = new FileInputStream("");
            
            // Create an InputStreamReader instance, specifying the character set to UTF-8            InputStreamReader isr = new InputStreamReader(fis, ("UTF-8"));
            
            // Read file content            int data;
            while ((data = ()) != -1) {
                ((char) data);
            }
            
            // Close the stream            ();
            ();
        } catch (IOException e) {
            ();
        }
    }
}

The run result is the same as in the previous example because the file is encoded in UTF-8.

Summarize

The above is personal experience. I hope you can give you a reference and I hope you can support me more.