SpringBoot--模板引擎Thymeleaf、使用&语法

傷城~ 2021-08-13 12:41 604阅读 0赞

## 3、模板引擎 ##

JSP、Velocity、Freemarker、Thymeleaf

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SpringBoot推荐的Thymeleaf；

语法更简单，功能更强大；

### 1、引入thymeleaf； ###

<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-thymeleaf</artifactId>
              	2.1.6
    		</dependency>
    切换thymeleaf版本
    <properties>
    		<thymeleaf.version>3.0.9.RELEASE</thymeleaf.version>
    		
    		
    		<thymeleaf-layout-dialect.version>2.2.2</thymeleaf-layout-dialect.version>
      </properties>

### 2、Thymeleaf使用 ###

@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";
      	//

只要我们把HTML页面放在classpath:/templates/，thymeleaf就能自动渲染；

使用：

1、导入thymeleaf的名称空间

2、使用thymeleaf语法；

<!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>

### 3、语法规则 ###

1）、th:text；改变当前元素里面的文本内容；

th：任意html属性；来替换原生属性的值

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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.
                    
                    ${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: _

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