使用Java将yaml转为properties，保证顺序、实测无BUG版本

本文介绍: 使用Jav a将yaml转为properties，保证顺序、实测无BUG版本

浏览了一圈网上的版本，大多存在以下问题：

基于此进行了优化，如果只是想直接转换，可直接使用我发布的在线版本
在这里插入图片描述
如果想在工程中使用，可继续往下看，源码在文末。

大部分代码都是使用了java.util.Properties类来转换，这个类是基于Con currentHa shMap来存储键值对的，必然会顺序错乱

这是截取的Properties类的部分源码：

/**
  * Properties does not store values in its inherited Hashtable, but instead
  * in an internal ConcurrentHashMap.  Synchronization is omitted from
  * simple read operations.  Writes and bulk operations remain synchronized,
  * as in Hashtable.
  */
private transient volatile ConcurrentHashMap<Object, Object&gt; map;

/**
     * Creates an empty property list with the specified defaults.
     *
     * @implNote The initial capacity of a {@code Properties} object created
     * with this constructor is unspecified.
     *
     * @param   defaults   the defaults.
     */
public Properties(Properties defaults) {
    this(defaults, 8);
}

private Properties(Properties defaults, int initialCapacity) {
    // use package-private constructor to
    // initialize unused fields with dummy values
    super((Void) null);
    map = new ConcurrentHashMap<&gt;(initialCapacity);
    this.defaults = defaults;

    // Ensure writes can't be reordered
    UNSAFE.storeFence();
}

主要还是代码不够严谨，解析的时候没有判断子节点是否是数组或对象，粗暴的转为String直接赋值了

import cn.hutool.core.util.StrUtil;
import lombok.extern.slf4j.Slf4j;
import org.yaml.snakeyaml.Yaml;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

@Slf4j
public class YamlUtil {

    /**
     * yaml 转 Properties
     *
     * @param input
     * @return
     */
    public static String castToProperties(String input) {
        Map<String, Object> propertiesMap = new LinkedHashMap<>();
        Map<String, Object> yamlMap = new Yaml().load(input);
        flattenMap("", yamlMap, propertiesMap);
        StringBuffer strBuff = new StringBuffer();
        propertiesMap.forEach((key, value) -> strBuff.append(key)
                .append("=")
                .append(value)
                .append(StrUtil.LF));
        return strBuff.toString();
    }

    /**
     * 递归 Map 集合，转为 Properties集合
     *
     * @param prefix
     * @param yamlMap
     * @param treeMap
     */
    private static void flattenMap(String prefix, Map<String, Object> yamlMap, Map<String, Object> treeMap) {
        yamlMap.forEach((key, value) -> {
            String fullKey = prefix + key;
            if (value instanceof LinkedHashMap) {
                flattenMap(fullKey + ".", (LinkedHashMap) value, treeMap);
            } else if (value instanceof ArrayList) {
                List values = (ArrayList) value;
                for (int i = 0; i < values.size(); i++) {
                    String itemKey = String.format("%s[%d]", fullKey, i);
                    Object itemValue = values.get(i);
                    if (itemValue instanceof String) {
                        treeMap.put(itemKey, itemValue);
                    } else {
                        flattenMap(itemKey + ".", (LinkedHashMap) itemValue, treeMap);
                    }
                }
            } else {
                treeMap.put(fullKey, value.toString());
            }
        });
    }

}