SpringBoot系列十：Thymeleaf

川长思鸟来 2022-01-21 08:57 318阅读 0赞

SpringBoot 推荐的 thymeleaf 模板引擎，语法更简单，功能更强大；  
一、引入 thymeleaf 依赖

<properties>
    	<thymeleaf.version>3.0.9.RELEASE</thymeleaf.version>
    	
    	<thymeleaf-layout-dialect.version>2.2.2</thymeleaf-layout-dialect.version>
    </properties>
    
    
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>

二、thymeleaf 使用  
1、只要我们把HTML页面放在`classpath:/templates/`下，thymeleaf 就能自动渲染。

@ConfigurationProperties(prefix = "spring.thymeleaf")
    public class ThymeleafProperties {
    
    	private static final Charset DEFAULT_ENCODING = Charset.forName("UTF-8");
    
    	private static final MimeType DEFAULT_CONTENT_TYPE = MimeType.valueOf("text/html");
    
    	public static final String DEFAULT_PREFIX = "classpath:/templates/";
    
    	public static final String DEFAULT_SUFFIX = ".html";
    	
    }

2、使用 thymeleaf

@RequestMapping("/success")
    public String success(Map<String,Object> map){
        //classpath:/templates/success.html
    
        map.put("hello","<h1>你好！</h1>");
        return "success";
    }

<!DOCTYPE html>
    
    <html lang="en" xmlns:th="http://www.thymeleaf.org">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
        <h1>成功！</h1>
        
        <div th:text="${hello}">这是显示欢迎信息</div>
    </body>
    </html>

三、thymeleaf 语法  
 官方网站：[https://www.thymeleaf.org/][https_www.thymeleaf.org]  
1、th：任意html属性，来替换原生属性的值。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpemhpcWlhbmcxMjE3_size_16_color_FFFFFF_t_70]  
2、表达式

Simple expressions:（表达式语法）
        Variable Expressions: ${...}：获取变量值；OGNL；
        		1）、获取对象的属性、调用方法
        		2）、使用内置的基本对象：
        			#ctx : the context object.
        			#vars: the context variables.
                    #locale : the context locale.
                    #request : (only in Web Contexts) the HttpServletRequest object.
                    #response : (only in Web Contexts) the HttpServletResponse object.
                    #session : (only in Web Contexts) the HttpSession object.
                    #servletContext : (only in Web Contexts) the ServletContext object.
                    
                    例子：${session.foo}
                3）、内置的一些工具对象：
    				#execInfo : information about the template being processed.
    				#messages : methods for obtaining externalized messages inside variables expressions, in the same way as they would be obtained using #{…} syntax.
    				#uris : methods for escaping parts of URLs/URIs
    				#conversions : methods for executing the configured conversion service (if any).
    				#dates : methods for java.util.Date objects: formatting, component extraction, etc.
    				#calendars : analogous to #dates , but for java.util.Calendar objects.
    				#numbers : methods for formatting numeric objects.
    				#strings : methods for String objects: contains, startsWith, prepending/appending, etc.
    				#objects : methods for objects in general.
    				#bools : methods for boolean evaluation.
    				#arrays : methods for arrays.
    				#lists : methods for lists.
    				#sets : methods for sets.
    				#maps : methods for maps.
    				#aggregates : methods for creating aggregates on arrays or collections.
    				#ids : methods for dealing with id attributes that might be repeated (for example, as a result of an iteration).
    
        Selection Variable Expressions: *{...}：选择表达式：和${}在功能上是一样；
        	补充：配合 th:object="${session.user}：
    	    <div th:object="${session.user}">
    		    <p>Name: <span th:text="*{firstName}">Sebastian</span>.</p>
    		    <p>Surname: <span th:text="*{lastName}">Pepper</span>.</p>
    		    <p>Nationality: <span th:text="*{nationality}">Saturn</span>.</p>
    	    </div>
        
        Message Expressions: #{...}：获取国际化内容
        
        Link URL Expressions: @{...}：定义URL；
        	 @{/order/process(execId=${execId},execType='FAST')}
        		
        Fragment Expressions: ~{...}：片段引用表达式
        	 <div th:insert="~{commons :: main}">...</div>
        		
    Literals（字面量）
          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:（文本操作）
        String concatenation: +
        Literal substitutions: |The name is ${name}|
    Arithmetic operations:（数学运算）
        Binary operators: + , - , * , / , %
        Minus sign (unary operator): -
    Boolean operations:（布尔运算）
        Binary operators: and , or
        Boolean negation (unary operator): ! , not
    Comparisons and equality:（比较运算）
        Comparators: > , < , >= , <= ( gt , lt , ge , le )
        Equality operators: == , != ( eq , ne )
    Conditional operators:条件运算（三元运算符）
        If-then: (if) ? (then)
        If-then-else: (if) ? (then) : (else)
        Default: (value) ?: (defaultvalue)
    Special tokens:
        No-Operation: _

3、测试：

@RequestMapping("/success")
    public String success(Map<String,Object> map){
        //classpath:/templates/success.html
    
        map.put("hello","<h1>你好！</h1>");
        map.put("users", Arrays.asList("zhangsan","lisi","wangwu"));
        return "success";
    }

<!DOCTYPE html>
    <html lang="en" xmlns:th="http://www.thymeleaf.org">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
        <h1>成功！</h1>
        
        <div id="div01" class="myDiv" th:id="${hello}" th:class="${hello}" th:text="${hello}">这是显示欢迎信息</div>
        <hr/>
        <div th:text="${hello}"></div>
        <div th:utext="${hello}"></div>
        <hr/>
        
        <h4 th:text="${user}" th:each="user: ${users}"></h4>
        <hr/>
        <h4>
            <span th:each="user: ${users}">[[${user}]]</span>
        </h4>
    </body>
    </html>

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpemhpcWlhbmcxMjE3_size_16_color_FFFFFF_t_70 1]  
4、thymeleaf 公共页面元素抽取

1、抽取公共片段
    <div th:fragment="copy">
    © 2011 The Good Thymes Virtual Grocery
    </div>
    
    2、引入公共片段
    <div th:insert="~{footer :: copy}"></div>
    ~{templatename::selector}：模板名::选择器
    ~{templatename::fragmentname}:模板名::片段名
    
    3、默认效果：
    insert的公共片段在div标签中
    如果使用th:insert等属性进行引入，可以不用写~{}：
    行内写法可以加上：[[~{}]];[(~{})]；

三种引入公共片段的 th 属性：  
 **th:insert**：将公共片段整个插入到声明引入的元素中。  
 **th:replace**：将声明引入的元素替换为公共片段。  
 **th:include**：将被引入的片段的内容包含进这个标签中。

<footer th:fragment="copy">
    © 2011 The Good Thymes Virtual Grocery
    </footer>
    
    引入方式
    <div th:insert="footer :: copy"></div>
    <div th:replace="footer :: copy"></div>
    <div th:include="footer :: copy"></div>
    
    效果
    <div>
        <footer>
        © 2011 The Good Thymes Virtual Grocery
        </footer>
    </div>
    
    <footer>
    © 2011 The Good Thymes Virtual Grocery
    </footer>
    
    <div>
    © 2011 The Good Thymes Virtual Grocery
    </div>

[https_www.thymeleaf.org]: https://www.thymeleaf.org/
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