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/model/FileAttribute.java

@@ -0,0 +1,69 @@
+package cn.keking.model;
+
+/**
+ * Created by kl on 2018/1/17.
+ * Content :
+ */
+public class FileAttribute {
+
+    private FileType type;
+
+    private String suffix;
+
+    private String name;
+
+    private String url;
+
+    private String decodedUrl;
+
+    public FileAttribute() {
+    }
+
+    public FileAttribute(FileType type, String suffix, String name, String url, String decodedUrl) {
+        this.type = type;
+        this.suffix = suffix;
+        this.name = name;
+        this.url = url;
+        this.decodedUrl = decodedUrl;
+    }
+
+    public FileType getType() {
+        return type;
+    }
+
+    public void setType(FileType type) {
+        this.type = type;
+    }
+
+    public String getSuffix() {
+        return suffix;
+    }
+
+    public void setSuffix(String suffix) {
+        this.suffix = suffix;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getUrl() {
+        return url;
+    }
+
+    public void setUrl(String url) {
+        this.url = url;
+    }
+
+    public String getDecodedUrl() {
+        return decodedUrl;
+    }
+
+    public void setDecodedUrl(String decodedUrl) {
+        this.decodedUrl = decodedUrl;
+    }
+}