Thymeleaf学习记录（8）--表达式基本对象

基础对象

#ctx：上下文对象

 /*
  * ======================================================================
  * See javadoc API for class org.thymeleaf.context.IContext
  * ======================================================================
  */

 ${#ctx.locale}
 ${#ctx.variables}

 /*
  * ======================================================================
  * See javadoc API for class org.thymeleaf.context.IWebContext
  * ======================================================================
  */

 ${#ctx.applicationAttributes}
 ${#ctx.httpServletRequest}
 ${#ctx.httpServletResponse}
 ${#ctx.httpSession}
 ${#ctx.requestAttributes}
 ${#ctx.requestParameters}
 ${#ctx.servletContext}
 ${#ctx.sessionAttributes}

#locale：直接访问java.util.Locale与当前请求关联的

#vars：org.thymeleaf.context.VariablesMap上下文中所有变量的实例（通常包含在#ctx.variables加本地变量中的变量）。

 /*
  * ======================================================================
  * See javadoc API for class org.thymeleaf.context.VariablesMap
  * ======================================================================
  */

 ${#vars.get('foo')}
 ${#vars.containsKey('foo')}
 ${#vars.size()}
 ...

请求/会话属性的Web上下文命名空间等。

• param：用于检索请求参数。${param.foo}是一个String[]带有foo请求参数值的，因此${param.foo[0]}通常用于获取第一个值。

 •    /*
 •     * ============================================================================
 •     * See javadoc API for class org.thymeleaf.context.WebRequestParamsVariablesMap
 •     * ============================================================================
 •     */
 •
 •    ${param.foo}              // Retrieves a String[] with the values of request parameter 'foo'
 •    ${param.size()}
 •    ${param.isEmpty()}
 •    ${param.containsKey('foo')}
 •    ...

• session：用于检索会话属性。

 •    /*
 •     * ======================================================================
 •     * See javadoc API for class org.thymeleaf.context.WebSessionVariablesMap
 •     * ======================================================================
 •     */
 •
 •    ${session.foo}                 // Retrieves the session atttribute 'foo'
 •    ${session.size()}
 •    ${session.isEmpty()}
 •    ${session.containsKey('foo')}
 •    ...

• application：用于检索应用程序/ servlet上下文属性。

 •    /*
 •     * =============================================================================
 •     * See javadoc API for class org.thymeleaf.context.WebServletContextVariablesMap
 •     * =============================================================================
 •     */
 •
 •    ${application.foo}              // Retrieves the ServletContext atttribute 'foo'
 •    ${application.size()}
 •    ${application.isEmpty()}
 •    ${application.containsKey('foo')}
 •    ...

Web上下文对象

#httpServletRequest：直接访问javax.servlet.http.HttpServletRequest与当前请求关联的对象

 ${#httpServletRequest.getAttribute('foo')}
 ${#httpServletRequest.getParameter('foo')}
 ${#httpServletRequest.getContextPath()}
 ${#httpServletRequest.getRequestName()}
 ...

• #httpSession：直接访问javax.servlet.http.HttpSession与当前请求关联的对象。

 •    ${#httpSession.getAttribute('foo')}
 •    ${#httpSession.id}
 •    ${#httpSession.lastAccessedTime}
 •    ...

Spring上下文对象

#themes：提供与Spring spring:themeJSP标记相同的功能

表达式实用程序对象

#dates：java.util.Date对象的实用方法

 /*
  * ======================================================================
  * 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：类似于#dates，但对于java.util.Calendar对象：

 •    /*
 •     * ======================================================================
 •     * 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：数字对象的实用方法：

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

• #strings：String对象的实用方法

 /*
  * ======================================================================
  * 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：一般对象的实用程序方法

 •    /*
 •     * ======================================================================
 •     * 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)}

• #bools：布尔评估的实用程序方法

 •    /*
 •     * ======================================================================
 •     * 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：数组的实用程序方法

 •    /*
 •     * ======================================================================
 •     * 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：列表的实用程序方法

 •    /*
 •     * ======================================================================
 •     * 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：集合的实用程序方法

 •    /*
 •     * ======================================================================
 •     * 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：地图的实用程序方法

 •    /*
 •     * ======================================================================
 •     * 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：用于在数组或集合上创建聚合的实用程序方法

 •    /*
 •     * ======================================================================
 •     * 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)}

• #messages：用于在变量表达式中获取外部化消息的实用程序方法，与使用#{...}语法获取它们的方式相同。

 •    /*
 •     * ======================================================================
 •     * 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)}

• #ids：用于处理id可能重复的属性的实用程序方法（例如，作为迭代的结果）。

 •    /*
 •     * ======================================================================
 •     * 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')}

使用示例：