java - FileInputStream 如何获取 File 的内容？

Question

我有一个文件f，我需要将其影响为FileInputStream fs：

File f = new File("C:/dir/foo.txt");
FileInputStream fs = (FileInputStream)f;

但我得到这个错误：

Cannot cast from File to FileInputStream

怎样才能fs得到内容f？

Answer 1

诀窍是这样的：

FileInputStream fs = new FileInputStream(f);

Answer 2

您可以使用这种方法：

    BufferedReader reader = new BufferedReader(new InputStreamReader(new BufferedInputStream(new FileInputStream(new File("text.txt")))));

    String line = null;

    while ((line = reader.readLine()) != null) {
        // do something with your read line
    }

或者这个：

    byte[] bytes = Files.readAllBytes(Paths.get("text.txt"));
    String text = new String(bytes, StandardCharsets.UTF_8);

Answer 3

在这里我找到了解决方案：

http://journals.ecs.soton.ac.uk/java/tutorial/java/io/filestreams.html