thymeleaf模板常见使用方法

####字符串拼接
```html
     // 字符串连接
	 <a th:href="'/detail/'+${blog.id}" target="_blank">
```

####数组判空

```javacript
	<div th:unless="${#arrays.isEmpty(blog.tagList)}" >
     	...                       
    </div>
```

####字符串判空

```javacript
	<div th:unless="${#strings.isEmpty(keyword)}" >
    </div>
```

####空代码块(th:block)
标签本身不显示
```javacript
<th:block>
</th:block>
```

####循环迭代

```javacript
// list为数组或集合，tag为list对象
<th:block th:each="tag:${list}">
     <a  class="tag" href="#" th:text="${tag}">HTML</a>
</th:block>
```

####条件判断
if条件
```javacript
<div th:if="${#strings.isEmpty(keyword)}"></div>
```
else条件
```javacript
<div th:unless="${#strings.isEmpty(keyword)}"></div>
```

###给JS变量初始化

```javascrip
// 字符串
var startTimeStr = "[[${temp}]]";
// 非字符串
var startTimeStr = [[${temp}]];

```

###三目运算

````html

<a th:class="${bookType} == '1' ? 'title_selected':'title_left'">基础</a>
````
###select下拉选择框的默认选中项
	<select class="form-control" id="gender" th:value="${user.gender}" >
		<option value="男" th:selected="${user.gender} eq '男'">男</option>
		<option value="女" th:selected="${user.gender} eq '女'">女</option>
	</select>
	
	
###是否包含(分大小写)
```html
<span th:if="${#strings.contains(name,'aa')}">包含aa</span> 
```

###更多方法

```html
${#strings.startsWith(name,'o')} 
${#strings.endsWith(name, 'o')} 
${#strings.indexOf(name,frag)}// 下标 
${#strings.substring(name,3,5)}// 截取 
${#strings.substringAfter(name,prefix)}// 从 prefix之后的一位开始截取到最后,比如 (ywj,y) = wj, 如果是(abccdefg,c) = cdefg//里面有2个c,取的是第一个c 
${#strings.substringBefore(name,suffix)}// 同上，不过是往前截取 
${#strings.replace(name,'las','ler')}// 替换 
${#strings.prepend(str,prefix)}// 拼字字符串在str前面 
${#strings.append(str,suffix)}// 和上面相反，接在后面 
${#strings.toUpperCase(name)} 
${#strings.toLowerCase(name)} 
${#strings.trim(str)} 
${#strings.length(str)} 
```