load config file(apollo-env.properties) from working directory first,…

… so that it behaves the same as spring boot config files

apollo-core/src/main/java/com/ctrip/framework/apollo/core/utils/ResourceUtils.java

@@ -9,16 +9,18 @@
 import java.io.InputStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.Enumeration;
 import java.util.Properties;
 
 public class ResourceUtils {
 
   private static final Logger logger = LoggerFactory.getLogger(ResourceUtils.class);
+  private static final String[] DEFAULT_FILE_SEARCH_LOCATIONS = new String[]{"./config/", "./"};
 
   @SuppressWarnings("unchecked")
   public static Properties readConfigFile(String configPath, Properties defaults) {
-    InputStream in = ClassLoaderUtil.getLoader().getResourceAsStream(configPath);
+    InputStream in = loadConfigFileFromDefaultSearchLocations(configPath);
     logger.debug("Reading config from resource {}", configPath);
     Properties props = new Properties();
     try {
@@ -65,4 +67,19 @@ public static Properties readConfigFile(String configPath, Properties defaults)
     }
     return props;
   }
+
+  private static InputStream loadConfigFileFromDefaultSearchLocations(String configPath) {
+    for (String searchLocation : DEFAULT_FILE_SEARCH_LOCATIONS) {
+      try {
+        File candidate = Paths.get(searchLocation, configPath).toFile();
+        if (candidate.exists() && candidate.isFile() && candidate.canRead()) {
+          return new FileInputStream(candidate);
+        }
+      } catch (Throwable ex) {
+        //ignore
+      }
+    }
+
+    return ClassLoaderUtil.getLoader().getResourceAsStream(configPath);
+  }
 }