java - 如何读取/写入用冒号 ':' 而不是等于 '=' 分隔键和值的属性文件

Question

我有包含键:值列表的属性文件，如下所示:

key1 : value1
key2 : value2

如何使用 Properties 类读取和写入该文件？可能还是不可能？

Answer 1

我查看了java Properties类(在jdk中)，发现java使用常量'='通过以下方法保存属性文件:

private void store0(BufferedWriter bw, String comments, boolean escUnicode)
    throws IOException
{
    if (comments != null) {
        writeComments(bw, comments);
    }
    bw.write("#" + new Date().toString());
    bw.newLine();
    synchronized (this) {
        for (Enumeration<?> e = keys(); e.hasMoreElements();) {
            String key = (String)e.nextElement();
            String val = (String)get(key);
            key = saveConvert(key, true, escUnicode);
            /* No need to escape embedded and trailing spaces for value, hence
             * pass false to flag.
             */
            val = saveConvert(val, false, escUnicode);
            bw.write(key + "=" + val);
            bw.newLine();
        }
    }
    bw.flush();
}

所以，无法处理我的属性文件。但是对于删除/写入我的属性文件，我发现该文件是 yaml 格式，我们可以通过此方法轻松读取文件:

public Map read(String path) {
    ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
    try {
        File file = new File(path);
        Map map = mapper.readValue(file, Map.class);
        return map;
    } catch (Exception e) {
        logger.error("Error during read Yml file {}", path, e);
    }
    return new HashMap();
}

并通过以下方法更新文件:

public boolean update(String path, Map content) {
    try {
        YAMLFactory yamlFactory = new YAMLFactory();
        yamlFactory.enable(YAMLGenerator.Feature.MINIMIZE_QUOTES);

        File file = new File(path);
        ObjectMapper mapper = new ObjectMapper(yamlFactory);
        ObjectWriter writer = mapper.writerWithDefaultPrettyPrinter();
        writer.writeValue(file, content);
        return true;
    } catch (Exception e) {
        logger.error("Error during save Yml file {}", path, e);
    }
    return false;
}

重要的是，我使用以下代码来防止对值使用双引号:

yamlFactory.enable(YAMLGenerator.Feature.MINIMIZE_QUOTES);