读取代码：

package com.jz.compute.mc.v2.config;import java.util.Enumeration;import java.util.ResourceBundle;import java.util.concurrent.ConcurrentHashMap;import java.util.concurrent.ConcurrentMap;public class PropertiesConfig {    public static volatile ConcurrentMap
     
       applicationMap = new ConcurrentHashMap<>();    private final static String dev = "dev";    private final static String test = "test";    private final static String prod = "prod";    private PropertiesConfig() {    }    public static ConcurrentMap
      
        getInstance() {        return getInstance("application-");    }    public static ConcurrentMap
       
         getInstance(String filePrefix) {        if (applicationMap.size() == 0) {            synchronized (PropertiesConfig.class) {                if (applicationMap.size() == 0) {                    ResourceBundle application = ResourceBundle.getBundle("application");                    ResourceBundle applicationActive = null;                    String profilesActive = application.containsKey("profiles.active")                            ? application.getString("profiles.active") : "";                    if (PropertiesConfig.prod.equals(profilesActive)) {                        applicationActive = ResourceBundle.getBundle(filePrefix + "prod");                    } else if (PropertiesConfig.test.equals(profilesActive)) {                        applicationActive = ResourceBundle.getBundle(filePrefix + "test");                    } else if (PropertiesConfig.dev.equals(profilesActive)) {                        applicationActive = ResourceBundle.getBundle(filePrefix + "dev");                    } else {                    }                    Enumeration
        
          keys = application.getKeys();                    while (keys.hasMoreElements()) {                        String key = keys.nextElement();                        applicationMap.put(key, application.getString(key));                    }                    if (null != applicationActive) {                        keys = applicationActive.getKeys();                        while (keys.hasMoreElements()) {                            String key = keys.nextElement();                            applicationMap.put(key, applicationActive.getString(key));                        }                    }                }            }        }        return applicationMap;    }    public static void main(String[] args) {        System.out.println(PropertiesConfig.getInstance().getOrDefault("eicost.url", ""));    }}