如何使用java将所有结果添加到for循环中的字符串

Question

我得到以下输出

for( Iterator <Object> it = results2.iterator();it.hasNext();)
            {
                BasicDBObject result  = (BasicDBObject) it.next();
                BasicDBObject dbo = (BasicDBObject) result.get("obj");
                String title2=(String) dbo.getString("Filename");
                        system.out.println("filename"+title2);
                 JsonArray finalResult = null;
                 JsonParser  parser = new JsonParser();
                 String tags2=dbo.getString("Tags");
                 JsonElement elem   = parser.parse(tags2);

                 finalResult = elem.getAsJsonArray();
                 for(int i=0;i<finalResult .size();i++)
                 {
                    JsonElement keys=finalResult.get(i);
                    System.out.println("final Result:"+keys);

                 }
}

输出：

filename:sample.pdf
finalresult:"java"
            "pdf"
            "c++"

filename:sample1.pdf
finalresult:"java1"
            "pdf"
            "c+"

但我希望通过删除重复项来获取所有文件的整体标记

filename:sample.pdf
filename:sample1.pdf
finalresult:"java"
            "pdf"
            "c++"
            "java1"
            "c+"

我在mondodb中的标记字段是

["java","php","c++]

你能建议我怎么做吗

感谢