Spring Boot 采用Thymeleaf模块及Thymeleaf语法

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Thymeleaf简介

Thymeleaf是⾯向Web和独⽴环境的现代服务器端Java模板引擎，能够处理HTML，XML，JavaScript，CSS甚⾄纯⽂本。

Thymeleaf旨在提供⼀个优雅的、⾼度可维护的创建模板的⽅式。为了实现这⼀⽬标，Thymeleaf建⽴在⾃然模板的概念上，将其逻辑注⼊到模板⽂件中，不会影响模板设计原型。这改善了设计的沟通，弥合了设计和开发团队之间的差距。

Thymeleaf从设计之初就遵循Web标准——特别是HTML5标准，如果需要，Thymeleaf允许您创建完全符合HTML5验证标准的模板。

在Spring Boot中使用

引入依赖


<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

配置文件


#thymeleaf start
spring.thymeleaf.mode=HTML5
spring.thymeleaf.encoding=UTF-8
spring.thymeleaf.content-type=text/html
#开发时关闭缓存,不然没法看到实时页面
spring.thymeleaf.cache=false
#thymeleaf end

resources/templates为thymeleaf模板默认路径

编写Controller


@Controller
public class TestController {
    @RequestMapping("/test")
    public String test(ModelMap map) {
        map.addAttribute("title", "Hello Thymeleaf!");
        return "test";
    }
}

编写test.html模块


<!DOCTYPE html>
<html xmlns="<http://www.w3.org/1999/xhtml>" xmlns:th="<http://www.thymeleaf.org>">
    <head>
        <title>测试</title>
    </head>
    <body>
        <h1 th:text="${title}">标题</h1>
    </body>
</html>

使用LEGACYHTML5模板

默认配置下，thymeleaf对.html的内容要求很严格，比如 <input name="id"/>，如果少最后的标签封闭符号/，就会报错而转到错误页。也比如你在使用Vue.js这样的库，然后有<div v-cloak></div>这样的html代码，也会被thymeleaf认为不符合要求而抛出错误。

解决这个问题可以通过设置thymeleaf模板为 LEGACYHTML5可以解决这个问题.LEGACYHTML5需要搭配一个额外的库 NekoHTML才可用。

引入依赖


<dependency>
    <groupId>net.sourceforge.nekohtml</groupId>
    <artifactId>nekohtml</artifactId>
    <version>1.9.22</version>
</dependency>

修改配置文件


#thymeleaf start
#采用LEGCYHTML5模板
spring.thymeleaf.mode=LEGACYHTML5
spring.thymeleaf.encoding=UTF-8
spring.thymeleaf.content-type=text/html
#开发时关闭缓存,不然没法看到实时页面
spring.thymeleaf.cache=false
#thymeleaf end

Thymeleaf语法

Thymeleaf简单表达式

变量表达式

Thymeleaf模板引擎在进行模板渲染时，还会附带一个Context存放进行模板渲染的变量，在模板中定义的表达式本质上就是从Context中获取对应的变量的值


<h1 th:text="${title}">标题</h1>

选择(星号)表达式

可以简单理解为内层对外层对象的引用


<div th:object="${user}">
    <p>Name: <span th:text="*{firstName}">Sebastian</span>.</p>
    <p>Surname: <span th:text="*{lastName}">Pepper</span>.</p>
</div>

以上代码等同于：


<div>
  <p>Name: <span th:text="${user.firstName}">Sebastian</span>.</p>
  <p>Surname: <span th:text="${user.lastName}">Pepper</span>.</p>
</div>

如何没有与 th:object结合使用，*{}与 ${}效果一样，因为其范围自动扩展到context。

URL表达式

URL表达式指的是把一个有用的上下文或会话信息添加到URL，这个过程经常被叫做URL重写。Thymeleaf对于URL的处理是通过语法@{…}来处理的


<!— 绝对路径 —>
<a href="details.html" th:href="@{<http://127.0.0.1/detail(id=${id})>}">view</a>

<!— 相对路径 带参数—>
<a href="details.html" th:href="@{/order/details(id=${id})}">view</a>

<!-- 把参数拼进路径中 -->
<a href="details.html" th:href="@{/order/{id}/details(id=${id})}">view</a>

Thymeleaf支持相对路径和绝对路径 (id=${id})表示将括号内的内容作为URL参数处理 @{...}表达式中可以通过{id}访问Context中的id变量 @{/order}是Context相关的相对路径，在渲染时会自动添加上当前Web应用的Context名字，假设context名字为app，那么结果应该是/app/order

文字国际化表达式

文字国际化表达式允许我们从一个外部文件获取区域文字信息(.properties) 使用Key-Value方式，还可以提供一组参数(可选).


#{main.title}
#{message.entrycreated(${entryId})}

模板引用:


<table>
    <th th:text="#{header.address.city}">...</th>
    <th th:text="#{header.address.country}">...</th>
</table>

Thymeleaf文本处理

字符串拼接


<span th:text="'Welcome to our application, ' + ${user.name} + '!'">

文字替换


<span th:text="|Welcome to our application, ${user.name}!|">

相比以上两种方式都可以实现字符串合并,但是,|…|中只能包含变量表达式${…}，不能包含其他常量、条件表达式等。

Thymeleaf表达基本对象

#ctx:上下文对象

#vars:上下文变量

#locale:上下文语言环境

#httpServletRequest:(只有在Web上下文)HttpServletRequest对象

#httpSession:(只有在Web上下文)HttpSession对象。

例如:


<span th:text="${#locale.country}">US</span>.

<div th:text="${#calendars.format(today,'dd MMMM yyyy')}"></div>

表达式预处理

表达式预处理，它被定义在_之间：


#{selection.__${sel.code}__}

${sel.code}将先被执行，结果(假如是AAA)将被看做表达式的一部分被执行,结果为 #{selection.AAA}。

Thymeleaf运算符

在表达式中可以使用各类算术运算符，例如+, -, *, /, %


<div th:with="isEven=(${prodStat.count} % 2 == 0)"></div>

逻辑运算符>, <, <=,>=，==,!=都可以使用需要注意的是使用 > ,<, >=, <=时需要用它的HTML转义符(> gt; < lt; >= ge; gte; <= le; lte; == eq; != ne; neq;)


<div th:if="${prodStat.count} > 1"></div>
<div th:text="'Execution mode is ' + ( (${execMode} == 'dev')? 'Development' : 'Production')"></div>

布尔运算符 and,or

Thymeleaf循环

数据集合必须是可以遍历的，使用 th:each标签：


  <table>
    <tr>
      <th>NAME</th>
      <th>PRICE</th>
      <th>IN STOCK</th>
    </tr>
    <tr th:each="prod : ${prods}">
      <td th:text="${prod.name}">Onions</td>
      <td th:text="${prod.price}">2.41</td>
      <td th:text="${prod.inStock}? #{true} : #{false}">yes</td>
    </tr>
  </table>

被循环渲染的元素<tr>中加入 th:each标签 th:each="prod : ${prods}"对集合变量prods进行遍历，对象prod在循环体中可通过表达式访问

Thymeleaf条件求值

If/Unless

Thymeleaf中使用 th:if和 th:unless属性进行条件判断

设置标签只有在 th:if中条件成立时才显示:


<a th:href="@{/login}" th:unless=${session.user != null}>Login</a>

th:unless与 th:if相反，表达式条件不成立时显示内容。

Switch

多路选择 Switch结构,默认属性 default,用 *表示


<div th:switch="${user.role}">
  <p th:case="'admin'">User is an administrator</p>
  <p th:case="#{roles.manager}">User is a manager</p>
  <p th:case="*">User is some other thing</p>
</div>

If-then-else

(if)?(then):else 三元运算符

三元运算控制 class属性选择


 <tr th:class="${row.even}? 'even' : 'odd'">

三元运算嵌套


 <tr th:class="${row.even}? (${row.first}? 'first' : 'even') : 'odd'">

还可以省略 else部分，当表达式结果为 false，返回 null，否则返回 alt


 <tr th:class="${row.even}? 'alt'"></tr>

If-then

(if) ? (then) ,省略了 else部分，如果条件不成立，返回 null

如果第一个表达式的计算结果为null，则取第二个表达式的结果


 <div th:object="${session.user}">
     <p>Age: <span th:text="*{age}?: '(no age specified)'">27</span>.</p>
 </div>

等效于：


<p>Age: <span th:text="*{age != null}? *{age} : '(no age specified)'">27</span>.</p>

条件表达式嵌套：


<p>Name: <span th:text="*{firstName} ?: (*{admin} ? 'Admin' : #{default.username})">Sebastian</span>.</p>

Expression Utility Objects

Thymeleaf提供了套Utility对象,内置于Context中,可通过#直接访问：

#execInfo : expression object providing useful information about the template being processed inside Thymeleaf Standard Expressions.

#uris : utility object for performing URI/URL operations (esp. escaping/unescaping) inside Thymeleaf Standard Expressions.

#conversions : utility object that allows the execution of the Conversion Service at any point of a template

#dates: java.util的实用方法。对象:日期格式、组件提取等.

#calendars: 类似于#日期,但对于 java.util。日历对象

#numbers: 格式化数字对象的实用方法。

#strings:字符串对象的实用方法:包含 startsWith,将/附加等。

#objects: 实用方法的对象。

#bools: 布尔评价的实用方法。

#arrays: 数组的实用方法。

#lists: list集合。

#sets:set集合。

#maps: map集合。

#aggregates: 实用程序方法用于创建聚集在数组或集合.

#messages: 实用程序方法获取外部信息内部变量表达式,以同样的方式,因为他们将获得使用# {…}语法

#ids: 实用程序方法来处理可能重复的id属性(例如,由于迭代)。

Execution Info

#execInfo : expression object providing useful information about the template being processed inside Thymeleaf Standard Expressions.


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.ExecutionInfo
 * ======================================================================
 */

/*
 * Return the name and mode of the 'leaf' template. This means the template
 * from where the events being processed were parsed. So if this piece of
 * code is not in the root template "A" but on a fragment being inserted
 * into "A" from another template called "B", this will return "B" as a
 * name, and B's mode as template mode.
 */
${#execInfo.templateName}
${#execInfo.templateMode}

/*
 * Return the name and mode of the 'root' template. This means the template
 * that the template engine was originally asked to process. So if this
 * piece of code is not in the root template "A" but on a fragment being
 * inserted into "A" from another template called "B", this will still
 * return "A" and A's template mode.
 */
${#execInfo.processedTemplateName}
${#execInfo.processedTemplateMode}

/*
 * Return the stacks (actually, List<String> or List<TemplateMode>) of
 * templates being processed. The first element will be the
 * 'processedTemplate' (the root one), the last one will be the 'leaf'
 * template, and in the middle all the fragments inserted in nested
 * manner to reach the leaf from the root will appear.
 */
${#execInfo.templateNames}
${#execInfo.templateModes}

/*
 * Return the stack of templates being processed similarly (and in the
 * same order) to 'templateNames' and 'templateModes', but returning
 * a List<TemplateData> with the full template metadata.
 */
${#execInfo.templateStack}

Messages

#messages : utility methods for obtaining externalized messages inside variables expressions, in the same way as they would be obtained using #{...} syntax.


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Messages
 * ======================================================================
 */

/*
 * Obtain externalized messages. Can receive a single key, a key plus arguments,
 * or an array/list/set of keys (in which case it will return an array/list/set of
 * externalized messages).
 * If a message is not found, a default message (like '??msgKey??') is returned.
 */
${#messages.msg('msgKey')}
${#messages.msg('msgKey', param1)}
${#messages.msg('msgKey', param1, param2)}
${#messages.msg('msgKey', param1, param2, param3)}
${#messages.msgWithParams('msgKey', new Object[] {param1, param2, param3, param4})}
${#messages.arrayMsg(messageKeyArray)}
${#messages.listMsg(messageKeyList)}
${#messages.setMsg(messageKeySet)}

/*
 * Obtain externalized messages or null. Null is returned instead of a default
 * message if a message for the specified key is not found.
 */
${#messages.msgOrNull('msgKey')}
${#messages.msgOrNull('msgKey', param1)}
${#messages.msgOrNull('msgKey', param1, param2)}
${#messages.msgOrNull('msgKey', param1, param2, param3)}
${#messages.msgOrNullWithParams('msgKey', new Object[] {param1, param2, param3, param4})}
${#messages.arrayMsgOrNull(messageKeyArray)}
${#messages.listMsgOrNull(messageKeyList)}
${#messages.setMsgOrNull(messageKeySet)}

URIs/URLs

#uris : utility object for performing URI/URL operations (esp. escaping/unescaping) inside Thymeleaf Standard Expressions.


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Uris
 * ======================================================================
 */

/*
 * Escape/Unescape as a URI/URL path
 */
${#uris.escapePath(uri)}
${#uris.escapePath(uri, encoding)}
${#uris.unescapePath(uri)}
${#uris.unescapePath(uri, encoding)}

/*
 * Escape/Unescape as a URI/URL path segment (between '/' symbols)
 */
${#uris.escapePathSegment(uri)}
${#uris.escapePathSegment(uri, encoding)}
${#uris.unescapePathSegment(uri)}
${#uris.unescapePathSegment(uri, encoding)}

/*
 * Escape/Unescape as a Fragment Identifier (#frag)
 */
${#uris.escapeFragmentId(uri)}
${#uris.escapeFragmentId(uri, encoding)}
${#uris.unescapeFragmentId(uri)}
${#uris.unescapeFragmentId(uri, encoding)}

/*
 * Escape/Unescape as a Query Parameter (?var=value)
 */
${#uris.escapeQueryParam(uri)}
${#uris.escapeQueryParam(uri, encoding)}
${#uris.unescapeQueryParam(uri)}
${#uris.unescapeQueryParam(uri, encoding)}

Conversions

#conversions : utility object that allows the execution of the Conversion Service at any point of a template:


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Conversions
 * ======================================================================
 */

/*
 * Execute the desired conversion of the 'object' value into the
 * specified class.
 */
${#conversions.convert(object, 'java.util.TimeZone')}
${#conversions.convert(object, targetClass)}
Dates

#dates : utility methods for java.util.Date objects:
/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Dates
 * ======================================================================
 */

/*
 * Format date with the standard locale format
 * Also works with arrays, lists or sets
 */
${#dates.format(date)}
${#dates.arrayFormat(datesArray)}
${#dates.listFormat(datesList)}
${#dates.setFormat(datesSet)}

/*
 * Format date with the ISO8601 format
 * Also works with arrays, lists or sets
 */
${#dates.formatISO(date)}
${#dates.arrayFormatISO(datesArray)}
${#dates.listFormatISO(datesList)}
${#dates.setFormatISO(datesSet)}

/*
 * Format date with the specified pattern
 * Also works with arrays, lists or sets
 */
${#dates.format(date, 'dd/MMM/yyyy HH:mm')}
${#dates.arrayFormat(datesArray, 'dd/MMM/yyyy HH:mm')}
${#dates.listFormat(datesList, 'dd/MMM/yyyy HH:mm')}
${#dates.setFormat(datesSet, 'dd/MMM/yyyy HH:mm')}

/*
 * Obtain date properties
 * Also works with arrays, lists or sets
 */
${#dates.day(date)}                    // also arrayDay(...), listDay(...), etc.
${#dates.month(date)}                  // also arrayMonth(...), listMonth(...), etc.
${#dates.monthName(date)}              // also arrayMonthName(...), listMonthName(...), etc.
${#dates.monthNameShort(date)}         // also arrayMonthNameShort(...), listMonthNameShort(...), etc.
${#dates.year(date)}                   // also arrayYear(...), listYear(...), etc.
${#dates.dayOfWeek(date)}              // also arrayDayOfWeek(...), listDayOfWeek(...), etc.
${#dates.dayOfWeekName(date)}          // also arrayDayOfWeekName(...), listDayOfWeekName(...), etc.
${#dates.dayOfWeekNameShort(date)}     // also arrayDayOfWeekNameShort(...), listDayOfWeekNameShort(...), etc.
${#dates.hour(date)}                   // also arrayHour(...), listHour(...), etc.
${#dates.minute(date)}                 // also arrayMinute(...), listMinute(...), etc.
${#dates.second(date)}                 // also arraySecond(...), listSecond(...), etc.
${#dates.millisecond(date)}            // also arrayMillisecond(...), listMillisecond(...), etc.

/*
 * Create date (java.util.Date) objects from its components
 */
${#dates.create(year,month,day)}
${#dates.create(year,month,day,hour,minute)}
${#dates.create(year,month,day,hour,minute,second)}
${#dates.create(year,month,day,hour,minute,second,millisecond)}

/*
 * Create a date (java.util.Date) object for the current date and time
 */
${#dates.createNow()}

${#dates.createNowForTimeZone()}

/*
 * Create a date (java.util.Date) object for the current date (time set to 00:00)
 */
${#dates.createToday()}

${#dates.createTodayForTimeZone()}

Calendars

#calendars : analogous to #dates, but for java.util.Calendar objects:


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Calendars
 * ======================================================================
 */

/*
 * Format calendar with the standard locale format
 * Also works with arrays, lists or sets
 */
${#calendars.format(cal)}
${#calendars.arrayFormat(calArray)}
${#calendars.listFormat(calList)}
${#calendars.setFormat(calSet)}

/*
 * Format calendar with the ISO8601 format
 * Also works with arrays, lists or sets
 */
${#calendars.formatISO(cal)}
${#calendars.arrayFormatISO(calArray)}
${#calendars.listFormatISO(calList)}
${#calendars.setFormatISO(calSet)}

/*
 * Format calendar with the specified pattern
 * Also works with arrays, lists or sets
 */
${#calendars.format(cal, 'dd/MMM/yyyy HH:mm')}
${#calendars.arrayFormat(calArray, 'dd/MMM/yyyy HH:mm')}
${#calendars.listFormat(calList, 'dd/MMM/yyyy HH:mm')}
${#calendars.setFormat(calSet, 'dd/MMM/yyyy HH:mm')}

/*
 * Obtain calendar properties
 * Also works with arrays, lists or sets
 */
${#calendars.day(date)}                // also arrayDay(...), listDay(...), etc.
${#calendars.month(date)}              // also arrayMonth(...), listMonth(...), etc.
${#calendars.monthName(date)}          // also arrayMonthName(...), listMonthName(...), etc.
${#calendars.monthNameShort(date)}     // also arrayMonthNameShort(...), listMonthNameShort(...), etc.
${#calendars.year(date)}               // also arrayYear(...), listYear(...), etc.
${#calendars.dayOfWeek(date)}          // also arrayDayOfWeek(...), listDayOfWeek(...), etc.
${#calendars.dayOfWeekName(date)}      // also arrayDayOfWeekName(...), listDayOfWeekName(...), etc.
${#calendars.dayOfWeekNameShort(date)} // also arrayDayOfWeekNameShort(...), listDayOfWeekNameShort(...), etc.
${#calendars.hour(date)}               // also arrayHour(...), listHour(...), etc.
${#calendars.minute(date)}             // also arrayMinute(...), listMinute(...), etc.
${#calendars.second(date)}             // also arraySecond(...), listSecond(...), etc.
${#calendars.millisecond(date)}        // also arrayMillisecond(...), listMillisecond(...), etc.

/*
 * Create calendar (java.util.Calendar) objects from its components
 */
${#calendars.create(year,month,day)}
${#calendars.create(year,month,day,hour,minute)}
${#calendars.create(year,month,day,hour,minute,second)}
${#calendars.create(year,month,day,hour,minute,second,millisecond)}

${#calendars.createForTimeZone(year,month,day,timeZone)}
${#calendars.createForTimeZone(year,month,day,hour,minute,timeZone)}
${#calendars.createForTimeZone(year,month,day,hour,minute,second,timeZone)}
${#calendars.createForTimeZone(year,month,day,hour,minute,second,millisecond,timeZone)}

/*
 * Create a calendar (java.util.Calendar) object for the current date and time
 */
${#calendars.createNow()}

${#calendars.createNowForTimeZone()}

/*
 * Create a calendar (java.util.Calendar) object for the current date (time set to 00:00)
 */
${#calendars.createToday()}

${#calendars.createTodayForTimeZone()}

Numbers

#numbers : utility methods for number objects:


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Numbers
 * ======================================================================
 */

/*
 * ==========================
 * Formatting integer numbers
 * ==========================
 */

/*
 * Set minimum integer digits.
 * Also works with arrays, lists or sets
 */
${#numbers.formatInteger(num,3)}
${#numbers.arrayFormatInteger(numArray,3)}
${#numbers.listFormatInteger(numList,3)}
${#numbers.setFormatInteger(numSet,3)}


/*
 * Set minimum integer digits and thousands separator:
 * 'POINT', 'COMMA', 'WHITESPACE', 'NONE' or 'DEFAULT' (by locale).
 * Also works with arrays, lists or sets
 */
${#numbers.formatInteger(num,3,'POINT')}
${#numbers.arrayFormatInteger(numArray,3,'POINT')}
${#numbers.listFormatInteger(numList,3,'POINT')}
${#numbers.setFormatInteger(numSet,3,'POINT')}


/*
 * ==========================
 * Formatting decimal numbers
 * ==========================
 */

/*
 * Set minimum integer digits and (exact) decimal digits.
 * Also works with arrays, lists or sets
 */
${#numbers.formatDecimal(num,3,2)}
${#numbers.arrayFormatDecimal(numArray,3,2)}
${#numbers.listFormatDecimal(numList,3,2)}
${#numbers.setFormatDecimal(numSet,3,2)}

/*
 * Set minimum integer digits and (exact) decimal digits, and also decimal separator.
 * Also works with arrays, lists or sets
 */
${#numbers.formatDecimal(num,3,2,'COMMA')}
${#numbers.arrayFormatDecimal(numArray,3,2,'COMMA')}
${#numbers.listFormatDecimal(numList,3,2,'COMMA')}
${#numbers.setFormatDecimal(numSet,3,2,'COMMA')}

/*
 * Set minimum integer digits and (exact) decimal digits, and also thousands and
 * decimal separator.
 * Also works with arrays, lists or sets
 */
${#numbers.formatDecimal(num,3,'POINT',2,'COMMA')}
${#numbers.arrayFormatDecimal(numArray,3,'POINT',2,'COMMA')}
${#numbers.listFormatDecimal(numList,3,'POINT',2,'COMMA')}
${#numbers.setFormatDecimal(numSet,3,'POINT',2,'COMMA')}


/*
 * =====================
 * Formatting currencies
 * =====================
 */

${#numbers.formatCurrency(num)}
${#numbers.arrayFormatCurrency(numArray)}
${#numbers.listFormatCurrency(numList)}
${#numbers.setFormatCurrency(numSet)}


/*
 * ======================
 * Formatting percentages
 * ======================
 */

${#numbers.formatPercent(num)}
${#numbers.arrayFormatPercent(numArray)}
${#numbers.listFormatPercent(numList)}
${#numbers.setFormatPercent(numSet)}

/*
 * Set minimum integer digits and (exact) decimal digits.
 */
${#numbers.formatPercent(num, 3, 2)}
${#numbers.arrayFormatPercent(numArray, 3, 2)}
${#numbers.listFormatPercent(numList, 3, 2)}
${#numbers.setFormatPercent(numSet, 3, 2)}


/*
 * ===============
 * Utility methods
 * ===============
 */

/*
 * Create a sequence (array) of integer numbers going
 * from x to y
 */
${#numbers.sequence(from,to)}
${#numbers.sequence(from,to,step)}

Strings

#strings : utility methods for String objects:


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Strings
 * ======================================================================
 */

/*
 * Null-safe toString()
 */
${#strings.toString(obj)}                           // also array*, list* and set*

/*
 * Check whether a String is empty (or null). Performs a trim() operation before check
 * Also works with arrays, lists or sets
 */
${#strings.isEmpty(name)}
${#strings.arrayIsEmpty(nameArr)}
${#strings.listIsEmpty(nameList)}
${#strings.setIsEmpty(nameSet)}

/*
 * Perform an 'isEmpty()' check on a string and return it if false, defaulting to
 * another specified string if true.
 * Also works with arrays, lists or sets
 */
${#strings.defaultString(text,default)}
${#strings.arrayDefaultString(textArr,default)}
${#strings.listDefaultString(textList,default)}
${#strings.setDefaultString(textSet,default)}

/*
 * Check whether a fragment is contained in a String
 * Also works with arrays, lists or sets
 */
${#strings.contains(name,'ez')}                     // also array*, list* and set*
${#strings.containsIgnoreCase(name,'ez')}           // also array*, list* and set*

/*
 * Check whether a String starts or ends with a fragment
 * Also works with arrays, lists or sets
 */
${#strings.startsWith(name,'Don')}                  // also array*, list* and set*
${#strings.endsWith(name,endingFragment)}           // also array*, list* and set*

/*
 * Substring-related operations
 * Also works with arrays, lists or sets
 */
${#strings.indexOf(name,frag)}                      // also array*, list* and set*
${#strings.substring(name,3,5)}                     // also array*, list* and set*
${#strings.substringAfter(name,prefix)}             // also array*, list* and set*
${#strings.substringBefore(name,suffix)}            // also array*, list* and set*
${#strings.replace(name,'las','ler')}               // also array*, list* and set*

/*
 * Append and prepend
 * Also works with arrays, lists or sets
 */
${#strings.prepend(str,prefix)}                     // also array*, list* and set*
${#strings.append(str,suffix)}                      // also array*, list* and set*

/*
 * Change case
 * Also works with arrays, lists or sets
 */
${#strings.toUpperCase(name)}                       // also array*, list* and set*
${#strings.toLowerCase(name)}                       // also array*, list* and set*

/*
 * Split and join
 */
${#strings.arrayJoin(namesArray,',')}
${#strings.listJoin(namesList,',')}
${#strings.setJoin(namesSet,',')}
${#strings.arraySplit(namesStr,',')}                // returns String[]
${#strings.listSplit(namesStr,',')}                 // returns List<String>
${#strings.setSplit(namesStr,',')}                  // returns Set<String>

/*
 * Trim
 * Also works with arrays, lists or sets
 */
${#strings.trim(str)}                               // also array*, list* and set*

/*
 * Compute length
 * Also works with arrays, lists or sets
 */
${#strings.length(str)}                             // also array*, list* and set*

/*
 * Abbreviate text making it have a maximum size of n. If text is bigger, it
 * will be clipped and finished in "..."
 * Also works with arrays, lists or sets
 */
${#strings.abbreviate(str,10)}                      // also array*, list* and set*

/*
 * Convert the first character to upper-case (and vice-versa)
 */
${#strings.capitalize(str)}                         // also array*, list* and set*
${#strings.unCapitalize(str)}                       // also array*, list* and set*

/*
 * Convert the first character of every word to upper-case
 */
${#strings.capitalizeWords(str)}                    // also array*, list* and set*
${#strings.capitalizeWords(str,delimiters)}         // also array*, list* and set*

/*
 * Escape the string
 */
${#strings.escapeXml(str)}                          // also array*, list* and set*
${#strings.escapeJava(str)}                         // also array*, list* and set*
${#strings.escapeJavaScript(str)}                   // also array*, list* and set*
${#strings.unescapeJava(str)}                       // also array*, list* and set*
${#strings.unescapeJavaScript(str)}                 // also array*, list* and set*

/*
 * Null-safe comparison and concatenation
 */
${#strings.equals(first, second)}
${#strings.equalsIgnoreCase(first, second)}
${#strings.concat(values...)}
${#strings.concatReplaceNulls(nullValue, values...)}

/*
 * Random
 */
${#strings.randomAlphanumeric(count)}

Objects

#objects : utility methods for objects in general


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Objects
 * ======================================================================
 */

/*
 * Return obj if it is not null, and default otherwise
 * Also works with arrays, lists or sets
 */
${#objects.nullSafe(obj,default)}
${#objects.arrayNullSafe(objArray,default)}
${#objects.listNullSafe(objList,default)}
${#objects.setNullSafe(objSet,default)}
Booleans

#bools : utility methods for boolean evaluation
/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Bools
 * ======================================================================
 */

/*
 * Evaluate a condition in the same way that it would be evaluated in a th:if tag
 * (see conditional evaluation chapter afterwards).
 * Also works with arrays, lists or sets
 */
${#bools.isTrue(obj)}
${#bools.arrayIsTrue(objArray)}
${#bools.listIsTrue(objList)}
${#bools.setIsTrue(objSet)}

/*
 * Evaluate with negation
 * Also works with arrays, lists or sets
 */
${#bools.isFalse(cond)}
${#bools.arrayIsFalse(condArray)}
${#bools.listIsFalse(condList)}
${#bools.setIsFalse(condSet)}

/*
 * Evaluate and apply AND operator
 * Receive an array, a list or a set as parameter
 */
${#bools.arrayAnd(condArray)}
${#bools.listAnd(condList)}
${#bools.setAnd(condSet)}

/*
 * Evaluate and apply OR operator
 * Receive an array, a list or a set as parameter
 */
${#bools.arrayOr(condArray)}
${#bools.listOr(condList)}
${#bools.setOr(condSet)}

Arrays

#arrays : utility methods for arrays


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Arrays
 * ======================================================================
 */

/*
 * Converts to array, trying to infer array component class.
 * Note that if resulting array is empty, or if the elements
 * of the target object are not all of the same class,
 * this method will return Object[].
 */
${#arrays.toArray(object)}

/*
 * Convert to arrays of the specified component class.
 */
${#arrays.toStringArray(object)}
${#arrays.toIntegerArray(object)}
${#arrays.toLongArray(object)}
${#arrays.toDoubleArray(object)}
${#arrays.toFloatArray(object)}
${#arrays.toBooleanArray(object)}

/*
 * Compute length
 */
${#arrays.length(array)}

/*
 * Check whether array is empty
 */
${#arrays.isEmpty(array)}

/*
 * Check if element or elements are contained in array
 */
${#arrays.contains(array, element)}
${#arrays.containsAll(array, elements)}

Lists

#lists : utility methods for lists


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Lists
 * ======================================================================
 */

/*
 * Converts to list
 */
${#lists.toList(object)}

/*
 * Compute size
 */
${#lists.size(list)}

/*
 * Check whether list is empty
 */
${#lists.isEmpty(list)}

/*
 * Check if element or elements are contained in list
 */
${#lists.contains(list, element)}
${#lists.containsAll(list, elements)}

/*
 * Sort a copy of the given list. The members of the list must implement
 * comparable or you must define a comparator.
 */
${#lists.sort(list)}
${#lists.sort(list, comparator)}

Sets

#sets : utility methods for sets


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Sets
 * ======================================================================
 */

/*
 * Converts to set
 */
${#sets.toSet(object)}

/*
 * Compute size
 */
${#sets.size(set)}

/*
 * Check whether set is empty
 */
${#sets.isEmpty(set)}

/*
 * Check if element or elements are contained in set
 */
${#sets.contains(set, element)}
${#sets.containsAll(set, elements)}

Maps

#maps : utility methods for maps


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Maps
 * ======================================================================
 */

/*
 * Compute size
 */
${#maps.size(map)}

/*
 * Check whether map is empty
 */
${#maps.isEmpty(map)}

/*
 * Check if key/s or value/s are contained in maps
 */
${#maps.containsKey(map, key)}
${#maps.containsAllKeys(map, keys)}
${#maps.containsValue(map, value)}
${#maps.containsAllValues(map, value)}

Aggregates

#aggregates : utility methods for creating aggregates on arrays or collections


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Aggregates
 * ======================================================================
 */

/*
 * Compute sum. Returns null if array or collection is empty
 */
${#aggregates.sum(array)}
${#aggregates.sum(collection)}

/*
 * Compute average. Returns null if array or collection is empty
 */
${#aggregates.avg(array)}
${#aggregates.avg(collection)}

IDs

#ids : utility methods for dealing with id attributes that might be repeated (for example, as a result of an iteration).


/*
 * ======================================================================
 * See javadoc API for class org.thymeleaf.expression.Ids
 * ======================================================================
 */

/*
 * Normally used in th:id attributes, for appending a counter to the id attribute value
 * so that it remains unique even when involved in an iteration process.
 */
${#ids.seq('someId')}

/*
 * Normally used in th:for attributes in <label> tags, so that these labels can refer to Ids
 * generated by means if the #ids.seq(...) function.
 *
 * Depending on whether the <label> goes before or after the element with the #ids.seq(...)
 * function, the "next" (label goes before "seq") or the "prev" function (label goes after
 * "seq") function should be called.
 */
${#ids.next('someId')}
${#ids.prev('someId')}

参考资料:Thymeleaf文档