Hello World

写代码的流程

数组

初始化数组（Inline array initialization）

常用的数组处理代码 Typical array-processing code

二维数组Two-dimensional arrays

内联初始化Inline initialization

类Class/class

文件

复制文件

public static void copyFile(File from, File to) throws IOException {
    File[] children = from.listFiles();
    if (children == null || children.length == 0) {
        if (from.isDirectory()) {
            to.mkdirs();
        } else {
            to.getParentFile().mkdirs();
            Files.copy(from.toPath(), to.toPath(), StandardCopyOption.REPLACE_EXISTING);
        }
    } else {
        for (File child : children) {
            copyFile(child, new File(to, child.getName()));
        }
    }
}

移动（move）文件

public static void moveFile(File from, File to) throws IOException {
    Files.move(from.toPath(), to.toPath(), StandardCopyOption.REPLACE_EXISTING);
}

读文件

public static List<String> readLines(File file) throws IOException {
        List<String> lines = new ArrayList<String>();
        try (BufferedReader br = new BufferedReader(new FileReader(file))) {
            String line = br.readLine();
            while (line != null) {
                lines.add(line);
                line = br.readLine();
            }
        }
        return lines;
}