JSP、Velocity、Freemarker、Thymeleaf都是模板引擎.
把模板和数据放到模板引擎中,然后解析输出.
SpringBoot推荐使用Thymeleaf；
Thymeleaf语法更简单，功能更强大.
1、引入Thymeleaf
maven依赖:
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf </artifactId>2.1.6 </dependency>
我们也可以自己到SpringBoot的官网找自己想要的版本.
但是要注意切换thymeleaf版本需要到maven的配置文件properties中设置,关于thymeleaf的版本一般都放在了github上搜索即可看到.
如果我们的thymeleaf是3版本以上的 layout2以上版本 .
<properties> <thymeleaf.version>3.0.9.RELEASE</thymeleaf.version> <thymeleaf-layout-dialect.version>2.2.2</thymeleaf-layout-dialect.version> </properties>
@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.
<html lang="en" xmlns:th="http://www.thymeleaf.org">
2、使用thymeleaf语法；
controller中携带一个参数,在html中获取
@RequestMapping("/success")
public String success(Model model){
model.addAttribute("msg","你好");
return "success";
}
<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <h1>你好啊</h1> <div th:text="${msg}"></div> </body> </html>
访问:localhost:8080/success 就可以获取到''你好''这个值了.
3.语法规则
(1)th:text:改变当前元素里面的文本内容
#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
他可以配合配合 th:object来用
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: _