字符流

  • 初始化变量

    1
    private static final String FILENAME = "E:" + File.separator + "hello.txt";

向文件中写入数据

1
2
3
4
5
6
7
8
9
10
11
12
private static void testWriteFile() {
    File file = new File(FILENAME);
    try {
        //如果是向文件追加内容，则改为 new FileWriter(file, true)
        Writer writer = new FileWriter(file);
        String txt = "Hello, World!";
        writer.write(txt);
        writer.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

从文件中读取内容

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
private static void testReadFile() {
    File file = new File(FILENAME);
    char[] chars = new char[100];
    try {
        Reader reader = new FileReader(file);
        int length = reader.read(chars);
        reader.close();
        System.out.println("读取长度：" + length);
        System.out.println("读取内容：" + new String(chars));
    } catch (IOException e) {
        e.printStackTrace();
    }
}

private static void testReadFileUnknownSize() {
    File file = new File(FILENAME);
    char[] chars = new char[100];
    try {
        Reader reader = new FileReader(file);
        int count = 0;
        int temp;
        while ((temp = reader.read()) != -1) {
            chars[count++] = (char) temp;
        }
        reader.close();
        System.out.println("读取内容：" + new String(chars));
    } catch (IOException e) {
        e.printStackTrace();
    }
}