diff --git a/src/main/java/im/zhaojun/zfile/model/entity/DriveConfig.java b/src/main/java/im/zhaojun/zfile/model/entity/DriveConfig.java
index fe72a20..84cec37 100644
--- a/src/main/java/im/zhaojun/zfile/model/entity/DriveConfig.java
+++ b/src/main/java/im/zhaojun/zfile/model/entity/DriveConfig.java
@@ -4,8 +4,6 @@ import im.zhaojun.zfile.model.enums.StorageTypeEnum;
 import lombok.Data;
 
 import javax.persistence.Entity;
-import javax.persistence.GeneratedValue;
-import javax.persistence.GenerationType;
 import javax.persistence.Id;
 
 /**
diff --git a/src/main/java/im/zhaojun/zfile/model/entity/FilterConfig.java b/src/main/java/im/zhaojun/zfile/model/entity/FilterConfig.java
index 9744219..42fca8a 100644
--- a/src/main/java/im/zhaojun/zfile/model/entity/FilterConfig.java
+++ b/src/main/java/im/zhaojun/zfile/model/entity/FilterConfig.java
@@ -2,12 +2,10 @@ package im.zhaojun.zfile.model.entity;
 
 import lombok.Data;
 
-import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.GenerationType;
 import javax.persistence.Id;
-import javax.persistence.Lob;
 
 /**
  * @author zhaojun
diff --git a/src/main/java/im/zhaojun/zfile/repository/FilterConfigRepository.java b/src/main/java/im/zhaojun/zfile/repository/FilterConfigRepository.java
index 33e1c02..6dd7774 100644
--- a/src/main/java/im/zhaojun/zfile/repository/FilterConfigRepository.java
+++ b/src/main/java/im/zhaojun/zfile/repository/FilterConfigRepository.java
@@ -14,13 +14,15 @@ public interface FilterConfigRepository extends JpaRepository<FilterConfig, Inte
 
     /**
      * 获取驱动器下的所有规则
-     * @param driveId   驱动器 ID
+     * @param       driveId
+     *              驱动器 ID
      */
     List<FilterConfig> findByDriveId(Integer driveId);
 
     /**
      * 根据驱动器 ID 删除其所有的规则
-     * @param driveId   驱动器 ID
+     * @param       driveId
+     *              驱动器 ID
      */
     void deleteByDriveId(Integer driveId);
 
diff --git a/src/main/java/im/zhaojun/zfile/service/FilterConfigService.java b/src/main/java/im/zhaojun/zfile/service/FilterConfigService.java
index 172ab83..4252adf 100644
--- a/src/main/java/im/zhaojun/zfile/service/FilterConfigService.java
+++ b/src/main/java/im/zhaojun/zfile/service/FilterConfigService.java
@@ -1,7 +1,5 @@
 package im.zhaojun.zfile.service;
 
-import cn.hutool.core.util.ArrayUtil;
-import cn.hutool.core.util.ReUtil;
 import cn.hutool.core.util.StrUtil;
 import im.zhaojun.zfile.model.entity.FilterConfig;
 import im.zhaojun.zfile.repository.FilterConfigRepository;
@@ -11,13 +9,9 @@ import org.springframework.transaction.annotation.Transactional;
 
 import javax.annotation.Resource;
 import java.nio.file.FileSystems;
-import java.nio.file.Path;
 import java.nio.file.PathMatcher;
 import java.nio.file.Paths;
-import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
-import java.util.Optional;
 
 /**
  * @author zhaojun
diff --git a/src/main/java/im/zhaojun/zfile/util/HttpUtil.java b/src/main/java/im/zhaojun/zfile/util/HttpUtil.java
index 1c6104d..aedc009 100644
--- a/src/main/java/im/zhaojun/zfile/util/HttpUtil.java
+++ b/src/main/java/im/zhaojun/zfile/util/HttpUtil.java
@@ -1,5 +1,6 @@
 package im.zhaojun.zfile.util;
 
+import cn.hutool.core.io.FileUtil;
 import im.zhaojun.zfile.exception.PreviewException;
 import im.zhaojun.zfile.model.constant.ZFileConstant;
 import lombok.extern.slf4j.Slf4j;
@@ -16,13 +17,19 @@ import java.net.URLConnection;
 public class HttpUtil {
 
     /**
-     * 最大支持文件预览大小: 1M
+     * 获取 URL 对应的文件内容
+     *
+     * @param   url
+     *          文件 URL
+     * @return  文件 URL
      */
     public static String getTextContent(String url) {
         RestTemplate restTemplate = SpringContextHolder.getBean("restTemplate");
 
-        if (getRemoteFileSize(url) > (1024 * ZFileConstant.TEXT_MAX_FILE_SIZE_KB)) {
-            throw new PreviewException("存储源跨域请求失败, 服务器中转状态, 预览文件超出大小, 最大支持 1M");
+        long maxFileSize = 1024 * ZFileConstant.TEXT_MAX_FILE_SIZE_KB;
+
+        if (getRemoteFileSize(url) > maxFileSize) {
+            throw new PreviewException("预览文件超出大小, 最大支持 " + FileUtil.readableFileSize(maxFileSize));
         }
 
         String result = restTemplate.getForObject(url, String.class);