inputstreamreader用法有哪些

InputStreamReader是Java中用于从InputStream读取数据的类，它将字节流转换为字符流。它有以下主要的用法：

从InputStream中读取数据，并将其转换为字符流：

InputStream inputStream = new FileInputStream("file.txt");Reader reader = new InputStreamReader(inputStream);int data = reader.read();while (data != -1) {    System.out.print((char) data);    data = reader.read();}reader.close();

指定字符编码格式：

InputStream inputStream = new FileInputStream("file.txt");Reader reader = new InputStreamReader(inputStream, "UTF-8");

使用BufferedReader包装InputStreamReader，以提高读取性能：

InputStream inputStream = new FileInputStream("file.txt");Reader reader = new InputStreamReader(inputStream);BufferedReader bufferedReader = new BufferedReader(reader);String line = bufferedReader.readLine();while (line != null) {    System.out.println(line);    line = bufferedReader.readLine();}bufferedReader.close();

使用try-with-resources来自动关闭流：

try (InputStream inputStream = new FileInputStream("file.txt");     Reader reader = new InputStreamReader(inputStream)) {    int data = reader.read();    while (data != -1) {        System.out.print((char) data);        data = reader.read();    }} catch (IOException e) {    e.printStackTrace();}