创建文件

判断文件夹是否存在，不存在则创建

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File file = new File(path);
if (!file.exists()) {
    file.mkdirs();
}

读取文件

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File file = new File(filePath);
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(file), "UTF-8"));
String row;
while ((row = reader.readLine()) != null) {
    System.out.println(row);
}

// 删除文件
file.delete();

reader.close();

写文件

  • 追加

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    try {
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file, true)));
        writer.write(content + "\t\n");
        writer.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

  • 覆盖

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    try {
        File file = new File("src/main/resources/application.properties");
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file)));
        writer.write(text);
        writer.close();
        return null;
    } catch (Exception e) {
        e.printStackTrace();
    }

文件大小

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readableFileSize(file.length())

/**
 * 文件大小转换
 * @param size
 * @return
 * @author muycode
 */
private String readableFileSize(long size) {
    if (size <= 0) return "0";
    final String[] units = new String[]{"B", "KB", "MB", "GB", "TB"};
    int digitGroups = (int) (Math.log10(size) / Math.log10(1024));
    return new DecimalFormat("#,##0.#").format(size / Math.pow(1024, digitGroups)) + " " + units[digitGroups];
}

获取属性值

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public static String getProperty(String configProperties, String key) {
    try {
        ResourceBundle resource = ResourceBundle.getBundle(configProperties);
        return resource.getString(key);
    } catch (Exception e) {
        e.printStackTrace();
    }
    try {

    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}