1.优化代码结构，抽象预览接口服务

2.新增更多图片预览格式支持

jodconverter-web/src/main/java/cn/keking/service/impl/PictureFilePreviewImpl.java

@@ -0,0 +1,37 @@
+package cn.keking.service.impl;
+
+import cn.keking.service.FilePreview;
+import cn.keking.utils.FileUtils;
+import com.google.common.collect.Lists;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+import org.springframework.ui.Model;
+import org.springframework.web.context.request.RequestContextHolder;
+
+import java.util.List;
+
+/**
+ * Created by kl on 2018/1/17.
+ * Content :图片文件处理
+ */
+@Service
+public class PictureFilePreviewImpl implements FilePreview {
+
+    @Autowired
+    FileUtils fileUtils;
+
+    @Override
+    public String filePreviewHandle(String url, Model model) {
+        String fileKey=(String) RequestContextHolder.currentRequestAttributes().getAttribute("fileKey",0);
+        List imgUrls = Lists.newArrayList(url);
+        try{
+            imgUrls.clear();
+            imgUrls.addAll(fileUtils.getRedisImgUrls(fileKey));
+        }catch (Exception e){
+            imgUrls = Lists.newArrayList(url);
+        }
+        model.addAttribute("imgurls", imgUrls);
+        model.addAttribute("currentUrl",url);
+        return "picture";
+    }
+}