Spring Boot thymeleaf模板引擎 Spring Boot thymeleaf模板引擎的使用详解
天门道人 人气:0在早期开发的时候,我们完成的都是静态页面也就是html页面,随着时间轴的发展,慢慢的引入了jsp页面,当在后端服务查询到数据之后可以转发到jsp页面,可以轻松的使用jsp页面来实现数据的显示及交互,jsp有非常强大的功能,但是,在使用springboot的时候,整个项目是以jar包的方式运行而不是war包,而且还嵌入了tomcat容器,因此,在默认情况下是不支持jsp页面的。如果直接以纯静态页面的方式会给我们的开发带来很大的麻烦,springboot推荐使用模板引擎。
模板引擎有很多种,jsp,freemarker,thymeleaf,模板引擎的作用就是我们来写一个页面模板,比如有些值呢,是动态的,我们写一些表达式。而这些值,从哪来呢,我们来组装一些数据,我们把这些数据找到。然后把这个模板和这个数据交给我们模板引擎,模板引擎按照我们这个数据帮你把这表达式解析、填充到我们指定的位置,然后把这个数据最终生成一个我们想要的内容给我们写出去,这就是我们这个模板引擎,不管是jsp还是其他模板引擎,都是这个思想。只不过不同的模板引擎语法不同而已,下面重点学习下springboot推荐使用的thymeleaf模板引擎,语法简单且功能强大
1、thymeleaf的介绍
官网地址:https://www.thymeleaf.org/
thymeleaf在github的地址:https://github.com/thymeleaf/thymeleaf
中文网站:https://raledong.gitbooks.io/using-thymeleaf/content/
导入依赖:
<!--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中有专门的thymeleaf配置类: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;
2、thymeleaf使用模板
在java代码中写入如下代码:
@RequestMapping("/hello") public String hello(Model model){ model.addAttribute("msg","Hello"); //classpath:/templates/hello.html return "hello"; }
html页面中写入如下代码:
<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <body> <h1>Hello</h1> <div th:text="${msg}"></div> </body> </html>
3、thymeleaf的表达式语法
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 ${name}| Arithmetic operations: Binary operators: +, -, *, /, % Minus sign (unary operator): - Boolean operations: Binary operators: and, or Boolean negation (unary operator): !, not Comparisons and equality: Comparators: >, <, >=, <= (gt, lt, ge, le) Equality operators: ==, != (eq, ne) Conditional operators: If-then: (if) ? (then) If-then-else: (if) ? (then) : (else) Default: (value) ?: (defaultvalue) Special tokens: No-Operation: _
4、thymeleaf实例演示
1、th的常用属性值
一、th:text :设置当前元素的文本内容,相同功能的还有th:utext,两者的区别在于前者不会转义html标签,后者会。优先级不高:order=7
二、th:value:设置当前元素的value值,类似修改指定属性的还有th:src,th:href。优先级不高:order=6
三、th:each:遍历循环元素,和th:text或th:value一起使用。注意该属性修饰的标签位置,详细往后看。优先级很高:order=2
四、th:if:条件判断,类似的还有th:unless,th:switch,th:case。优先级较高:order=3
五、th:insert:代码块引入,类似的还有th:replace,th:include,三者的区别较大,若使用不恰当会破坏html结构,常用于公共代码块提取的场景。优先级最高:order=1
六、th:fragment:定义代码块,方便被th:insert引用。优先级最低:order=8
七、th:object:声明变量,一般和*{}一起配合使用,达到偷懒的效果。优先级一般:order=4
八、th:attr:修改任意属性,实际开发中用的较少,因为有丰富的其他th属性帮忙,类似的还有th:attrappend,th:attrprepend。优先级一般:order=5
thymeleaf.html
<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <p th:text="${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设置文本内容 <b>加粗</b>"); map.put("thUText","th:utext 设置文本内容 <b>加粗</b>"); map.put("thValue","thValue 设置当前元素的value值"); map.put("thEach","Arrays.asList(\"th:each\", \"遍历列表\")"); map.put("thIf","msg is not null"); map.put("thObject",new Person("zhangsan",12,"男")); return "thymeleaf"; } }
2、标准表达式语法
${...} 变量表达式,Variable Expressions
*{...} 选择变量表达式,Selection Variable Expressions
一、可以获取对象的属性和方法
二、可以使用ctx,vars,locale,request,response,session,servletContext内置对象
session.setAttribute("user","zhangsan"); th:text="${session.user}"
三、可以使用dates,numbers,strings,objects,arrays,lists,sets,maps等内置方法
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:数值格式化方法,常用的方法有:formatDecimal等 三、bools:布尔方法,常用的方法有:isTrue,isFalse等 四、arrays:数组方法,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:对象方法,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内置方法</title> </head> <body> <h3>#strings </h3> <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="${#strings.contains(Str, 'IT')}"/></p> </div> <h3>#numbers </h3> <div> <p>formatDecimal 整数部分随意,小数点后保留两位,四舍五入: <span th:text="${#numbers.formatDecimal(Num, 0, 2)}"/></p> <p>formatDecimal 整数部分保留五位数,小数点后保留两位,四舍五入: <span th:text="${#numbers.formatDecimal(Num, 5, 2)}"/></p> </div> <h3>#bools </h3> <div th:if="${#bools.isTrue(Bool)}"> <p th:text="${Bool}"></p> </div> <h3>#arrays </h3> <div th:if="${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="${#arrays.containsAll(Array, Array)}"/></p> </div> <h3>#lists </h3> <div th:if="${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="${#lists.sort(List)}"/></p> </div> <h3>#maps </h3> <div th:if="${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="${#maps.containsValue(hashMap, '#maps')}"/></p> </div> <h3>#dates </h3> <div> <p>format : <span th:text="${#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", "变量表达式内置方法"); map.put("Map", hashMap); map.put("Date", new Date()); map.put("Num", 888.888D); return "standardExpression"; }
@{...} 链接表达式,Link URL Expressions
<!-- 不管是静态资源的引用,form表单的请求,凡是链接都可以用@{...} 。这样可以动态获取项目路径,即便项目名变了,依然可以正常访问 链接表达式结构 无参:@{/xxx} 有参:@{/xxx(k1=v1,k2=v2)} 对应url结构:xxx?k1=v1&k2=v2 引入本地资源:@{/项目本地的资源路径} 引入外部资源:@{/webjars/资源在jar包中的路径} --> <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>
#{...} 消息表达式,Message Expressions
<!-- 消息表达式一般用于国际化的场景。结构:th:text="#{msg}" -->
~{...} 代码块表达式,Fragment Expressions
fragment.html
<!-- 支持两种语法结构 推荐:~{templatename::fragmentname} 支持:~{templatename::#id} templatename:模版名,Thymeleaf会根据模版名解析完整路:/resources/templates/templatename.html,要注意文件的路径。 fragmentname:片段名,Thymeleaf通过th:fragment声明定义代码块,即:th:fragment="fragmentname" id:HTML的id选择器,使用时要在前面加上#号,不支持class选择器。 代码块表达式的使用 代码块表达式需要配合th属性(th:insert,th:replace,th:include)一起使用。 th:insert:将代码块片段整个插入到使用了th:insert的HTML标签中, th:replace:将代码块片段整个替换使用了th:replace的HTML标签中, th:include:将代码块片段包含的内容插入到使用了th:include的HTML标签中, --> <!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <!--th:fragment定义代码块标识--> <footer th:fragment="copy"> 2019 The Good Thymes Virtual Grocery </footer> <!--三种不同的引入方式--> <div th:insert="fragment::copy"></div> <div th:replace="fragment::copy"></div> <div th:include="fragment::copy"></div> <!--th:insert是在div中插入代码块,即多了一层div--> <div> <footer> © 2011 The Good Thymes Virtual Grocery </footer> </div> <!--th:replace是将代码块代替当前div,其html结构和之前一致--> <footer> © 2011 The Good Thymes Virtual Grocery </footer> <!--th:include是将代码块footer的内容插入到div中,即少了一层footer--> <div> © 2011 The Good Thymes Virtual Grocery </div> </body> </html>
5、国际化的配置
在很多应用场景下,我们需要实现页面的国际化,springboot对国际化有很好的支持, 下面来演示对应的效果。
1、在idea中设置统一的编码格式,file->settings->Editors->File Encoding,选择编码格式为utf-8
2、在resources资源文件下创建一个i8n的目录,创建一个login.properties的文件,还有login_zh_CN.properties,idea会自动识别国际化操作
3、创建三个不同的文件,名称分别是:login.properties,login_en_US.properties,login_zh_CN.properties
内容如下:
#login.properties login.password=密码1 login.remmber=记住我1 login.sign=登录1 login.username=用户名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=密码~ login.remmber=记住我~ login.sign=登录~ login.username=用户名~
4、配置国际化的资源路径
spring: messages: basename: i18n/login
5、编写html页面
初始html页面 <!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> 修改后的页面 <!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>
可以看到通过浏览器的切换语言已经能够实现,想要通过超链接实现的话,如下所示:
添加WebMVCConfig.java代码
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页面修改为:
<!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>
国际化的源码解释:
//MessageSourceAutoConfiguration public class MessageSourceAutoConfiguration { private static final Resource[] NO_RESOURCES = new Resource[0]; public MessageSourceAutoConfiguration() { } @Bean @ConfigurationProperties(prefix = "spring.messages") //我们的配置文件可以直接放在类路径下叫: messages.properties, 就可以进行国际化操作了 public MessageSourceProperties messageSourceProperties() { return new MessageSourceProperties(); } @Bean public MessageSource messageSource(MessageSourceProperties properties) { ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource(); if (StringUtils.hasText(properties.getBasename())) { //设置国际化文件的基础名(去掉语言国家代码的) 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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