非拉丁字符显示为“？”

Question

我有一个像name.label=名我的java代码就像Properties properties = new Properties();try (FileInputStream inputStream = new FileInputStream(path)) {    Reader reader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));    properties.load(reader);    System.out.println("Name label: " + properties.getProperty("name.label"));    reader.close();} catch (FileNotFoundException e) {    log.debug("Couldn't find properties file. ", e);} catch (IOException e) {    log.debug("Couldn't close input stream. ", e);}但它打印姓名标签： ?我正在使用java 8。

Answer 1

替换字符可能表示文件未使用指定的CharSet.

根据您构建阅读器的方式，您将获得有关格式错误输入的不同默认行为。

当你使用

Properties properties = new Properties();

try(FileInputStream inputStream = new FileInputStream(path);

    Reader reader = new InputStreamReader(inputStream, StandardCharsets.UTF_8)) {

    properties.load(reader);

    System.out.println("Name label: " + properties.getProperty("name.label"));

} catch(FileNotFoundException e) {

    log.debug("Couldn't find properties file. ", e);

} catch(IOException e) {

    log.debug("Couldn't read properties file. ", e);

}

你得到一个Reader配置CharsetDecoder为替换无效输入的。相反，当您使用

Properties properties = new Properties();

try(Reader reader = Files.newBufferedReader(Paths.get(path))) { // default to UTF-8

    properties.load(reader);

    System.out.println("Name label: " + properties.getProperty("name.label"));

} catch(FileNotFoundException e) {

    log.debug("Couldn't find properties file. ", e);

} catch(IOException e) {

    log.debug("Couldn't read properties file. ", e);

}

将CharsetDecoder被配置为在格式错误的输入上引发异常。

为了完整起见，如果两个默认值都不符合您的需求，您可以通过以下方式配置行为：

Properties properties = new Properties();

CharsetDecoder dec = StandardCharsets.UTF_8.newDecoder()

    .onMalformedInput(CodingErrorAction.REPLACE)

    .replaceWith("!");

try(FileInputStream inputStream = new FileInputStream(path);

    Reader reader = new InputStreamReader(inputStream, dec)) {

    properties.load(reader);

    System.out.println("Name label: " + properties.getProperty("name.label"));

} catch(FileNotFoundException e) {

    log.debug("Couldn't find properties file. ", e);

} catch(IOException e) {

    log.debug("Couldn't read properties file. ", e);

}

另见CharsetDecoder和CodingErrorAction。