<body class="signin" th:style="'background:url(' + @{(${bgimgPath})} + ');'" >
</body>
map.put("bgimgPath","/image/backgroundImage.png");
<body class="signin" th:style="'background:url(' + @{(${bgimgPath})} + ');'" >
</body>
map.put("bgimgPath","/image/backgroundImage.png");