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本篇內(nèi)容主要講解“如何使用Spring Boot thymeleaf模板引擎”,感興趣的朋友不妨來看看。本文介紹的方法操作簡單快捷,實(shí)用性強(qiáng)。下面就讓小編來帶大家學(xué)習(xí)“如何使用Spring Boot thymeleaf模板引擎”吧!
在早期開發(fā)的時(shí)候,我們完成的都是靜態(tài)頁面也就是html頁面,隨著時(shí)間軸的發(fā)展,慢慢的引入了jsp頁面,當(dāng)在后端服務(wù)查詢到數(shù)據(jù)之后可以轉(zhuǎn)發(fā)到j(luò)sp頁面,可以輕松的使用jsp頁面來實(shí)現(xiàn)數(shù)據(jù)的顯示及交互,jsp有非常強(qiáng)大的功能,但是,在使用springboot的時(shí)候,整個(gè)項(xiàng)目是以jar包的方式運(yùn)行而不是war包,而且還嵌入了tomcat容器,因此,在默認(rèn)情況下是不支持jsp頁面的。如果直接以純靜態(tài)頁面的方式會給我們的開發(fā)帶來很大的麻煩,springboot推薦使用模板引擎。
模板引擎有很多種,jsp,freemarker,thymeleaf,模板引擎的作用就是我們來寫一個(gè)頁面模板,比如有些值呢,是動態(tài)的,我們寫一些表達(dá)式。而這些值,從哪來呢,我們來組裝一些數(shù)據(jù),我們把這些數(shù)據(jù)找到。然后把這個(gè)模板和這個(gè)數(shù)據(jù)交給我們模板引擎,模板引擎按照我們這個(gè)數(shù)據(jù)幫你把這表達(dá)式解析、填充到我們指定的位置,然后把這個(gè)數(shù)據(jù)最終生成一個(gè)我們想要的內(nèi)容給我們寫出去,這就是我們這個(gè)模板引擎,不管是jsp還是其他模板引擎,都是這個(gè)思想。只不過不同的模板引擎語法不同而已,下面重點(diǎn)學(xué)習(xí)下springboot推薦使用的thymeleaf模板引擎,語法簡單且功能強(qiáng)大
導(dǎo)入依賴:
<!--thymeleaf模板--> <dependency> <groupId>org.thymeleaf</groupId> <artifactId>thymeleaf-spring5</artifactId> </dependency> <dependency> <groupId>org.thymeleaf.extras</groupId> <artifactId>thymeleaf-extras-java8time</artifactId> </dependency>
在springboot中有專門的thymeleaf配置類:ThymeleafProperties
@ConfigurationProperties(prefix = "spring.thymeleaf") public class ThymeleafProperties { private static final Charset DEFAULT_ENCODING = StandardCharsets.UTF_8; public static final String DEFAULT_PREFIX = "classpath:/templates/"; public static final String DEFAULT_SUFFIX = ".html"; /** * Whether to check that the template exists before rendering it. */ private boolean checkTemplate = true; /** * Whether to check that the templates location exists. */ private boolean checkTemplateLocation = true; /** * Prefix that gets prepended to view names when building a URL. */ private String prefix = DEFAULT_PREFIX; /** * Suffix that gets appended to view names when building a URL. */ private String suffix = DEFAULT_SUFFIX; /** * Template mode to be applied to templates. See also Thymeleaf's TemplateMode enum. */ private String mode = "HTML"; /** * Template files encoding. */ private Charset encoding = DEFAULT_ENCODING; /** * Whether to enable template caching. */ private boolean cache = true;
在java代碼中寫入如下代碼:
@RequestMapping("/hello") public String hello(Model model){ model.addAttribute("msg","Hello"); //classpath:/templates/hello.html return "hello"; }
html頁面中寫入如下代碼:
<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <body> <h2>Hello</h2> <div th:text="${msg}"></div> </body> </html>
Simple expressions: Variable Expressions: ${...} Selection Variable Expressions: *{...} Message Expressions: #{...} Link URL Expressions: @{...} Fragment Expressions: ~{...} Literals Text literals: 'one text', 'Another one!',… Number literals: 0, 34, 3.0, 12.3,… Boolean literals: true, false Null literal: null Literal tokens: one, sometext, main,… Text operations: String concatenation: + Literal substitutions: |The name is ${name}| Arithmetic operations: Binary operators: +, -, *, /, % Minus sign (unary operator): - Boolean operations: Binary operators: and, or Boolean negation (unary operator): !, not Comparisons and equality: Comparators: >, <, >=, <= (gt, lt, ge, le) Equality operators: ==, != (eq, ne) Conditional operators: If-then: (if) ? (then) If-then-else: (if) ? (then) : (else) Default: (value) ?: (defaultvalue) Special tokens: No-Operation: _
1、th的常用屬性值
一、th:text :設(shè)置當(dāng)前元素的文本內(nèi)容,相同功能的還有th:utext,兩者的區(qū)別在于前者不會轉(zhuǎn)義html標(biāo)簽,后者會。優(yōu)先級不高:order=7
二、th:value:設(shè)置當(dāng)前元素的value值,類似修改指定屬性的還有th:src,th:href。優(yōu)先級不高:order=6
三、th:each:遍歷循環(huán)元素,和th:text或th:value一起使用。注意該屬性修飾的標(biāo)簽位置,詳細(xì)往后看。優(yōu)先級很高:order=2
四、th:if:條件判斷,類似的還有th:unless,th:switch,th:case。優(yōu)先級較高:order=3
五、th:insert:代碼塊引入,類似的還有th:replace,th:include,三者的區(qū)別較大,若使用不恰當(dāng)會破壞html結(jié)構(gòu),常用于公共代碼塊提取的場景。優(yōu)先級最高:order=1
六、th:fragment:定義代碼塊,方便被th:insert引用。優(yōu)先級最低:order=8
七、th:object:聲明變量,一般和*{}一起配合使用,達(dá)到偷懶的效果。優(yōu)先級一般:order=4
八、th:attr:修改任意屬性,實(shí)際開發(fā)中用的較少,因?yàn)橛胸S富的其他th屬性幫忙,類似的還有th:attrappend,th:attrprepend。優(yōu)先級一般:order=5
thymeleaf.html
<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <p th:text="${thText}"></p> <p th:utext="${thUText}"></p> <input type="text" th:value="${thValue}"> <div th:each="message:${thEach}"> <p th:text="${message}"></p> </div> <div> <p th:text="${message}" th:each="message:${thEach}"></p> </div> <p th:text="${thIf}" th:if="${not #strings.isEmpty(thIf)}"></p> <div th:object="${thObject}"> <p>name:<span th:text="*{name}"/></p> <p>age:<span th:text="*{age}"/></p> <p>gender:<span th:text="*{gender}"/></p> </div> </body> </html>
ThymeleafController.java
import org.springframework.stereotype.Controller; import org.springframework.ui.ModelMap; import org.springframework.web.bind.annotation.RequestMapping; @Controller public class ThymeleafController { @RequestMapping("thymeleaf") public String thymeleaf(ModelMap map){ map.put("thText","th:text設(shè)置文本內(nèi)容 <b>加粗</b>"); map.put("thUText","th:utext 設(shè)置文本內(nèi)容 <b>加粗</b>"); map.put("thValue","thValue 設(shè)置當(dāng)前元素的value值"); map.put("thEach","Arrays.asList(\"th:each\", \"遍歷列表\")"); map.put("thIf","msg is not null"); map.put("thObject",new Person("zhangsan",12,"男")); return "thymeleaf"; } }
2、標(biāo)準(zhǔn)表達(dá)式語法
${...} 變量表達(dá)式,Variable Expressions
*{...} 選擇變量表達(dá)式,Selection Variable Expressions
一、可以獲取對象的屬性和方法
二、可以使用ctx,vars,locale,request,response,session,servletContext內(nèi)置對象
session.setAttribute("user","zhangsan"); th:text="${session.user}"
三、可以使用dates,numbers,strings,objects,arrays,lists,sets,maps等內(nèi)置方法
standardExpression.html
<!-- 一、strings:字符串格式化方法,常用的Java方法它都有。比如:equals,equalsIgnoreCase,length,trim,toUpperCase,toLowerCase,indexOf,substring,replace,startsWith,endsWith,contains,containsIgnoreCase等 二、numbers:數(shù)值格式化方法,常用的方法有:formatDecimal等 三、bools:布爾方法,常用的方法有:isTrue,isFalse等 四、arrays:數(shù)組方法,常用的方法有:toArray,length,isEmpty,contains,containsAll等 五、lists,sets:集合方法,常用的方法有:toList,size,isEmpty,contains,containsAll,sort等 六、maps:對象方法,常用的方法有:size,isEmpty,containsKey,containsValue等 七、dates:日期方法,常用的方法有:format,year,month,hour,createNow等 --> <!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>thymeleaf內(nèi)置方法</title> </head> <body> <h4>#strings </h4> <div th:if="${not #strings.isEmpty(Str)}" > <p>Old Str : <span th:text="${Str}"/></p> <p>toUpperCase : <span th:text="${#strings.toUpperCase(Str)}"/></p> <p>toLowerCase : <span th:text="${#strings.toLowerCase(Str)}"/></p> <p>equals : <span th:text="${#strings.equals(Str, 'blog')}"/></p> <p>equalsIgnoreCase : <span th:text="${#strings.equalsIgnoreCase(Str, 'blog')}"/></p> <p>indexOf : <span th:text="${#strings.indexOf(Str, 'r')}"/></p> <p>substring : <span th:text="${#strings.substring(Str, 2, 4)}"/></p> <p>replace : <span th:text="${#strings.replace(Str, 'it', 'IT')}"/></p> <p>startsWith : <span th:text="${#strings.startsWith(Str, 'it')}"/></p> <p>contains : <span th:text="${#strings.contains(Str, 'IT')}"/></p> </div> <h4>#numbers </h4> <div> <p>formatDecimal 整數(shù)部分隨意,小數(shù)點(diǎn)后保留兩位,四舍五入: <span th:text="${#numbers.formatDecimal(Num, 0, 2)}"/></p> <p>formatDecimal 整數(shù)部分保留五位數(shù),小數(shù)點(diǎn)后保留兩位,四舍五入: <span th:text="${#numbers.formatDecimal(Num, 5, 2)}"/></p> </div> <h4>#bools </h4> <div th:if="${#bools.isTrue(Bool)}"> <p th:text="${Bool}"></p> </div> <h4>#arrays </h4> <div th:if="${not #arrays.isEmpty(Array)}"> <p>length : <span th:text="${#arrays.length(Array)}"/></p> <p>contains : <span th:text="${#arrays.contains(Array,2)}"/></p> <p>containsAll : <span th:text="${#arrays.containsAll(Array, Array)}"/></p> </div> <h4>#lists </h4> <div th:if="${not #lists.isEmpty(List)}"> <p>size : <span th:text="${#lists.size(List)}"/></p> <p>contains : <span th:text="${#lists.contains(List, 0)}"/></p> <p>sort : <span th:text="${#lists.sort(List)}"/></p> </div> <h4>#maps </h4> <div th:if="${not #maps.isEmpty(hashMap)}"> <p>size : <span th:text="${#maps.size(hashMap)}"/></p> <p>containsKey : <span th:text="${#maps.containsKey(hashMap, 'thName')}"/></p> <p>containsValue : <span th:text="${#maps.containsValue(hashMap, '#maps')}"/></p> </div> <h4>#dates </h4> <div> <p>format : <span th:text="${#dates.format(Date)}"/></p> <p>custom format : <span th:text="${#dates.format(Date, 'yyyy-MM-dd HH:mm:ss')}"/></p> <p>day : <span th:text="${#dates.day(Date)}"/></p> <p>month : <span th:text="${#dates.month(Date)}"/></p> <p>monthName : <span th:text="${#dates.monthName(Date)}"/></p> <p>year : <span th:text="${#dates.year(Date)}"/></p> <p>dayOfWeekName : <span th:text="${#dates.dayOfWeekName(Date)}"/></p> <p>hour : <span th:text="${#dates.hour(Date)}"/></p> <p>minute : <span th:text="${#dates.minute(Date)}"/></p> <p>second : <span th:text="${#dates.second(Date)}"/></p> <p>createNow : <span th:text="${#dates.createNow()}"/></p> </div> </body> </html>
ThymeleafController.java
@RequestMapping("standardExpression") public String standardExpression(ModelMap map){ map.put("Str", "Blog"); map.put("Bool", true); map.put("Array", new Integer[]{1,2,3,4}); map.put("List", Arrays.asList(1,3,2,4,0)); Map hashMap = new HashMap(); hashMap.put("thName", "${#...}"); hashMap.put("desc", "變量表達(dá)式內(nèi)置方法"); map.put("Map", hashMap); map.put("Date", new Date()); map.put("Num", 888.888D); return "standardExpression"; }
@{...} 鏈接表達(dá)式,Link URL Expressions
<!-- 不管是靜態(tài)資源的引用,form表單的請求,凡是鏈接都可以用@{...} 。這樣可以動態(tài)獲取項(xiàng)目路徑,即便項(xiàng)目名變了,依然可以正常訪問 鏈接表達(dá)式結(jié)構(gòu) 無參:@{/xxx} 有參:@{/xxx(k1=v1,k2=v2)} 對應(yīng)url結(jié)構(gòu):xxx?k1=v1&k2=v2 引入本地資源:@{/項(xiàng)目本地的資源路徑} 引入外部資源:@{/webjars/資源在jar包中的路徑} --> <link th:href="@{/webjars/bootstrap/4.0.0/css/bootstrap.css}" rel="external nofollow" rel="stylesheet"> <link th:href="@{/main/css/123.css}" rel="external nofollow" rel="stylesheet"> <form class="form-login" th:action="@{/user/login}" th:method="post" > <a class="btn btn-sm" th:href="@{/login.html(l='zh_CN')}" rel="external nofollow" >中文</a> <a class="btn btn-sm" th:href="@{/login.html(l='en_US')}" rel="external nofollow" >English</a>
#{...} 消息表達(dá)式,Message Expressions
<!-- 消息表達(dá)式一般用于國際化的場景。結(jié)構(gòu):th:text="#{msg}" -->
~{...} 代碼塊表達(dá)式,F(xiàn)ragment Expressions
fragment.html
<!-- 支持兩種語法結(jié)構(gòu) 推薦:~{templatename::fragmentname} 支持:~{templatename::#id} templatename:模版名,Thymeleaf會根據(jù)模版名解析完整路:/resources/templates/templatename.html,要注意文件的路徑。 fragmentname:片段名,Thymeleaf通過th:fragment聲明定義代碼塊,即:th:fragment="fragmentname" id:HTML的id選擇器,使用時(shí)要在前面加上#號,不支持class選擇器。 代碼塊表達(dá)式的使用 代碼塊表達(dá)式需要配合th屬性(th:insert,th:replace,th:include)一起使用。 th:insert:將代碼塊片段整個(gè)插入到使用了th:insert的HTML標(biāo)簽中, th:replace:將代碼塊片段整個(gè)替換使用了th:replace的HTML標(biāo)簽中, th:include:將代碼塊片段包含的內(nèi)容插入到使用了th:include的HTML標(biāo)簽中, --> <!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <!--th:fragment定義代碼塊標(biāo)識--> <footer th:fragment="copy"> 2019 The Good Thymes Virtual Grocery </footer> <!--三種不同的引入方式--> <div th:insert="fragment::copy"></div> <div th:replace="fragment::copy"></div> <div th:include="fragment::copy"></div> <!--th:insert是在div中插入代碼塊,即多了一層div--> <div> <footer> © 2011 The Good Thymes Virtual Grocery </footer> </div> <!--th:replace是將代碼塊代替當(dāng)前div,其html結(jié)構(gòu)和之前一致--> <footer> © 2011 The Good Thymes Virtual Grocery </footer> <!--th:include是將代碼塊footer的內(nèi)容插入到div中,即少了一層footer--> <div> © 2011 The Good Thymes Virtual Grocery </div> </body> </html>
在很多應(yīng)用場景下,我們需要實(shí)現(xiàn)頁面的國際化,springboot對國際化有很好的支持, 下面來演示對應(yīng)的效果。
1、在idea中設(shè)置統(tǒng)一的編碼格式,file->settings->Editors->File Encoding,選擇編碼格式為utf-8
2、在resources資源文件下創(chuàng)建一個(gè)i8n的目錄,創(chuàng)建一個(gè)login.properties的文件,還有l(wèi)ogin_zh_CN.properties,idea會自動識別國際化操作
3、創(chuàng)建三個(gè)不同的文件,名稱分別是:login.properties,login_en_US.properties,login_zh_CN.properties
內(nèi)容如下:
#login.properties login.password=密碼1 login.remmber=記住我1 login.sign=登錄1 login.username=用戶名1 #login_en_US.properties login.password=Password login.remmber=Remember Me login.sign=Sign In login.username=Username #login_zh_CN.properties login.password=密碼~ login.remmber=記住我~ login.sign=登錄~ login.username=用戶名~
4、配置國際化的資源路徑
spring: messages: basename: i18n/login
5、編寫html頁面
初始html頁面 <!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"/> <title>Title</title> </head> <body> <form action="" method="post"> <label >Username</label> <input type="text" name="username" placeholder="Username" > <label >Password</label> <input type="password" name="password" placeholder="Password" > <br> <br> <div> <label> <input type="checkbox" value="remember-me"/> Remember Me </label> </div> <br> <button type="submit">Sign in</button> <br> <br> <a>中文</a> <a>English</a> </form> </body> </html> 修改后的頁面 <!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"/> <title>Title</title> </head> <body> <form action="" method="post"> <label th:text="#{login.username}">Username</label> <input type="text" name="username" placeholder="Username" th:placeholder="#{login.username}"> <label th:text="#{login.password}">Password</label> <input type="password" name="password" placeholder="Password" th:placeholder="#{login.password}"> <br> <br> <div> <label> <input type="checkbox" value="remember-me"/> [[#{login.remmber}]] </label> </div> <br> <button type="submit" th:text="#{login.sign}">Sign in</button> <br> <br> <a>中文</a> <a>English</a> </form> </body> </html>
可以看到通過瀏覽器的切換語言已經(jīng)能夠?qū)崿F(xiàn),想要通過超鏈接實(shí)現(xiàn)的話,如下所示:
添加WebMVCConfig.java代碼
import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.util.StringUtils; import org.springframework.web.servlet.LocaleResolver; import org.springframework.web.servlet.config.annotation.ViewControllerRegistry; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.util.Locale; @Configuration public class WebMVCConfig implements WebMvcConfigurer { @Override public void addViewControllers(ViewControllerRegistry registry) { registry.addViewController("/").setViewName("login"); registry.addViewController("/login.html").setViewName("login"); } @Bean public LocaleResolver localeResolver(){ return new NativeLocaleResolver(); } protected static class NativeLocaleResolver implements LocaleResolver{ @Override public Locale resolveLocale(HttpServletRequest request) { String language = request.getParameter("language"); Locale locale = Locale.getDefault(); if(!StringUtils.isEmpty(language)){ String[] split = language.split("_"); locale = new Locale(split[0],split[1]); } return locale; } @Override public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale locale) { } } }
login.html頁面修改為:
<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"/> <title>Title</title> </head> <body> <form action="" method="post"> <label th:text="#{login.username}">Username</label> <input type="text" name="username" placeholder="Username" th:placeholder="#{login.username}"> <label th:text="#{login.password}">Password</label> <input type="password" name="password" placeholder="Password" th:placeholder="#{login.password}"> <br> <br> <div> <label> <input type="checkbox" value="remember-me"/> [[#{login.remmber}]] </label> </div> <br> <button type="submit" th:text="#{login.sign}">Sign in</button> <br> <br> <a th:href="@{/login.html(language='zh_CN')}" rel="external nofollow" >中文</a> <a th:href="@{/login.html(language='en_US')}" rel="external nofollow" >English</a> </form> </body> </html>
國際化的源碼解釋:
//MessageSourceAutoConfiguration public class MessageSourceAutoConfiguration { private static final Resource[] NO_RESOURCES = new Resource[0]; public MessageSourceAutoConfiguration() { } @Bean @ConfigurationProperties(prefix = "spring.messages") //我們的配置文件可以直接放在類路徑下叫: messages.properties, 就可以進(jìn)行國際化操作了 public MessageSourceProperties messageSourceProperties() { return new MessageSourceProperties(); } @Bean public MessageSource messageSource(MessageSourceProperties properties) { ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource(); if (StringUtils.hasText(properties.getBasename())) { //設(shè)置國際化文件的基礎(chǔ)名(去掉語言國家代碼的) messageSource.setBasenames(StringUtils.commaDelimitedListToStringArray(StringUtils.trimAllWhitespace(properties.getBasename()))); } if (properties.getEncoding() != null) { messageSource.setDefaultEncoding(properties.getEncoding().name()); } messageSource.setFallbackToSystemLocale(properties.isFallbackToSystemLocale()); Duration cacheDuration = properties.getCacheDuration(); if (cacheDuration != null) { messageSource.setCacheMillis(cacheDuration.toMillis()); } messageSource.setAlwaysUseMessageFormat(properties.isAlwaysUseMessageFormat()); messageSource.setUseCodeAsDefaultMessage(properties.isUseCodeAsDefaultMessage()); return messageSource; } } //WebMvcAutoConfiguration @Bean @ConditionalOnMissingBean @ConditionalOnProperty(prefix = "spring.mvc", name = "locale") public LocaleResolver localeResolver() { if (this.mvcProperties.getLocaleResolver() == WebMvcProperties.LocaleResolver.FIXED) { return new FixedLocaleResolver(this.mvcProperties.getLocale()); } AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver(); localeResolver.setDefaultLocale(this.mvcProperties.getLocale()); return localeResolver; } //AcceptHeaderLocaleResolver @Override public Locale resolveLocale(HttpServletRequest request) { Locale defaultLocale = getDefaultLocale(); if (defaultLocale != null && request.getHeader("Accept-Language") == null) { return defaultLocale; } Locale requestLocale = request.getLocale(); List<Locale> supportedLocales = getSupportedLocales(); if (supportedLocales.isEmpty() || supportedLocales.contains(requestLocale)) { return requestLocale; } Locale supportedLocale = findSupportedLocale(request, supportedLocales); if (supportedLocale != null) { return supportedLocale; } return (defaultLocale != null ? defaultLocale : requestLocale); }
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