Thymeleaf 3.0教程：19 附录B:表达式实用程序对象(二)
字符串
#strings : 字符串对象的实用工具
/*
* ======================================================================
* 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)}对象
#objects : 常规对象的实用方法
/*
* ======================================================================
* 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)}
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)}数组
#arrays : 数组的实用方法
/*
* ======================================================================
* 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)}列表
#lists : 列表对象的实用方法
/*
* ======================================================================
* 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
#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 : map对象的实用方法
/*
* ======================================================================
* 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)}聚合
#aggregates :在数组或集合上创建聚合的实用方法
/*
* ======================================================================
* 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)}ID
#ids : 用于处理可能重复的id属性的实用方法(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')}