一 前言

浏览了一圈网上的版本，大多存在以下问题：

• 转换后顺序错乱
• 遗漏子节点

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

如果想在工程中使用，可继续往下看，源码在文末。

1.1 顺序错乱的原因

大部分代码都是使用了java.util.Properties类来转换，这个类是基于ConcurrentHashMap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> 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 valuessuper((Void) null);map = new ConcurrentHashMap<>(initialCapacity);this.defaults = defaults;// Ensure writes can't be reorderedUNSAFE.storeFence();
}

1.2 遗漏子节点的原因

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

二、优化措施

• 基于LinkedHashMap来存储键值对

• 递归遍历时判断子节点类型，不同类型采用不同的处理方式

三、源码

import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.util.StrUtil;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.CollectionUtils;import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;/*** @author Deng.Weiping* @since 2023/11/28 13:57*/
@Slf4j
public class PropertiesParser {/*** Properties 转 Yaml** @param input* @return*/public static String castToYaml(String input) {try {Map<String, Object> properties = readProperties(input);return properties2Yaml(properties);} catch (Exception e) {log.error("property 转 Yaml 转换失败", e);}return null;}private static Map<String, Object> readProperties(String input) {// 使用 LinkedHashMap 保证顺序Map<String, Object> propertiesMap = new LinkedHashMap<>();for (String line : input.split(StrUtil.LF)) {if (StrUtil.isNotBlank(line)) {// 使用正则表达式解析每一行中的键值对Pattern pattern = Pattern.compile("\\s*([^=\\s]*)\\s*=\\s*(.*)\\s*");Matcher matcher = pattern.matcher(line);if (matcher.matches()) {String key = matcher.group(1);String value = matcher.group(2);propertiesMap.put(key, value);}}}return propertiesMap;}/*** properties 格式转化为 yaml 格式字符串** @param properties* @return*/private static String properties2Yaml(Map<String, Object> properties) {if (CollUtil.isEmpty(properties)) {return null;}Map<String, Object> map = parseToMap(properties);StringBuffer stringBuffer = map2Yaml(map);return stringBuffer.toString();}/*** 递归解析为 LinkedHashMap** @param propMap* @return*/private static Map<String, Object> parseToMap(Map<String, Object> propMap) {Map<String, Object> resultMap = new LinkedHashMap<>();try {if (CollectionUtils.isEmpty(propMap)) {return resultMap;}propMap.forEach((key, value) -> {if (key.contains(".")) {String currentKey = key.substring(0, key.indexOf("."));if (resultMap.get(currentKey) != null) {return;}Map<String, Object> childMap = getChildMap(propMap, currentKey);Map<String, Object> map = parseToMap(childMap);resultMap.put(currentKey, map);} else {resultMap.put(key, value);}});} catch (Exception e) {e.printStackTrace();}return resultMap;}/*** 获取拥有相同父级节点的子节点** @param propMap* @param currentKey* @return*/private static Map<String, Object> getChildMap(Map<String, Object> propMap, String currentKey) {Map<String, Object> childMap = new LinkedHashMap<>();try {propMap.forEach((key, value) -> {if (key.contains(currentKey + ".")) {key = key.substring(key.indexOf(".") + 1);childMap.put(key, value);}});} catch (Exception e) {e.printStackTrace();}return childMap;}/*** map集合转化为yaml格式字符串** @param map* @return*/public static StringBuffer map2Yaml(Map<String, Object> map) {//默认deep 为零，表示不空格，deep 每加一层，缩进两个空格return map2Yaml(map, 0);}/*** 把Map集合转化为yaml格式 String字符串** @param propMap map格式配置文件* @param deep    树的层级，默认deep 为零，表示不空格，deep 每加一层，缩进两个空格* @return*/private static StringBuffer map2Yaml(Map<String, Object> propMap, int deep) {StringBuffer yamlBuffer = new StringBuffer();try {if (CollectionUtils.isEmpty(propMap)) {return yamlBuffer;}String space = getSpace(deep);for (Map.Entry<String, Object> entry : propMap.entrySet()) {Object valObj = entry.getValue();if (entry.getKey().contains("[") && entry.getKey().contains("]")) {String key = entry.getKey().substring(0, entry.getKey().indexOf("[")) + ":";yamlBuffer.append(space + key + "\n");propMap.forEach((itemKey, itemValue) -> {if (itemKey.startsWith(key.substring(0, entry.getKey().indexOf("[")))) {yamlBuffer.append(getSpace(deep + 1) + "- ");if (itemValue instanceof Map) {StringBuffer valStr = map2Yaml((Map<String, Object>) itemValue, 0);String[] split = valStr.toString().split(StrUtil.LF);for (int i = 0; i < split.length; i++) {if (i > 0) {yamlBuffer.append(getSpace(deep + 2));}yamlBuffer.append(split[i]).append(StrUtil.LF);}} else {yamlBuffer.append(itemValue + "\n");}}});break;} else {String key = space + entry.getKey() + ":";if (valObj instanceof String) { //值为value 类型，不用再继续遍历yamlBuffer.append(key + " " + valObj + "\n");} else if (valObj instanceof List) { //yaml List 集合格式yamlBuffer.append(key + "\n");List<String> list = (List<String>) entry.getValue();String lSpace = getSpace(deep + 1);for (String str : list) {yamlBuffer.append(lSpace + "- " + str + "\n");}} else if (valObj instanceof Map) { //继续递归遍历Map<String, Object> valMap = (Map<String, Object>) valObj;yamlBuffer.append(key + "\n");StringBuffer valStr = map2Yaml(valMap, deep + 1);yamlBuffer.append(valStr.toString());} else {yamlBuffer.append(key + " " + valObj + "\n");}}}} catch (Exception e) {e.printStackTrace();}return yamlBuffer;}/*** 获取缩进空格** @param deep* @return*/private static String getSpace(int deep) {StringBuffer buffer = new StringBuffer();if (deep == 0) {return "";}for (int i = 0; i < deep; i++) {buffer.append("  ");}return buffer.toString();}}