// 合并 ---------------------------------------------------
        StringBuilder strBuilder = new StringBuilder(fileName);
        strBuilder.append("/r/n");
        strBuilder.append(subject);
        strBuilder.append("/r/n");
        strBuilder.append(category);
        System.out.println(strBuilder.toString());
        
        // 拆分 ---------------------------------------------------
        String[] strDest = strBuilder.toString().split("/r/n");
        if(strDest.length != 3)
            System.err.println("error: strDest.length != 3");
        
        // fileName
        System.out.println("fileName: " + strDest[0]);
        
        // subject
        System.out.println("subject: " + strDest[1]);
        
        // category
        System.out.println("category: " + strDest[2]);

------解决方案--------------------
str.split("/");