#421 Create SpawnLoader

- Non-static service class which handles the spawnpoints used in AuthMe

src/main/java/fr/xephi/authme/util/FileUtils.java

@@ -0,0 +1,52 @@
+package fr.xephi.authme.util;
+
+import fr.xephi.authme.AuthMe;
+import fr.xephi.authme.ConsoleLogger;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+
+import static java.lang.String.format;
+
+/**
+ * File utilities.
+ */
+public class FileUtils {
+
+    private FileUtils() {
+    }
+
+    /**
+     * Copy a resource file (from the JAR) to the given file if it doesn't exist.
+     *
+     * @param destinationFile The file to check and copy to (outside of JAR)
+     * @param resourcePath Absolute path to the resource file (path to file within JAR)
+     * @return False if the file does not exist and could not be copied, true otherwise
+     */
+    public static boolean copyFileFromResource(File destinationFile, String resourcePath) {
+        if (destinationFile.exists()) {
+            return true;
+        } else if (!destinationFile.getParentFile().exists() && !destinationFile.getParentFile().mkdirs()) {
+            ConsoleLogger.showError("Cannot create parent directories for '" + destinationFile + "'");
+            return false;
+        }
+
+        // ClassLoader#getResourceAsStream does not deal with the '\' path separator: replace to '/'
+        final String normalizedPath = resourcePath.replace("\\", "/");
+        try (InputStream is = AuthMe.class.getClassLoader().getResourceAsStream(normalizedPath)) {
+            if (is == null) {
+                ConsoleLogger.showError(format("Cannot copy resource '%s' to file '%s': cannot load resource",
+                    resourcePath, destinationFile.getPath()));
+            } else {
+                Files.copy(is, destinationFile.toPath());
+                return true;
+            }
+        } catch (IOException e) {
+            ConsoleLogger.logException(format("Cannot copy resource '%s' to file '%s':",
+                resourcePath, destinationFile.getPath()), e);
+        }
+        return false;
+    }
+}