模板引擎
模板引擎作用：根据页面模板和数据生成展示页面
初识Thymeleaf
引入Thymeleaf
Thymeleaf 官网：https://www.thymeleaf.org/
Thymeleaf 在Github 的主页：https://github.com/thymeleaf/thymeleaf
Spring官方文档：https://docs.spring.io/spring-boot/docs/2.2.5.RELEASE/reference/htmlsingle/#using-boot-starter
<dependency> <groupId>org.thymeleaf</groupId> <artifactId>thymeleaf-spring5</artifactId> </dependency> <dependency> <groupId>org.thymeleaf.extras</groupId> <artifactId>thymeleaf-extras-java8time</artifactId> </dependency>
编写模板
1、模板位置（两次敲击Shift）
@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";
2、thymeleaf应用
https://www.thymeleaf.org/doc/tutorials/3.0/usingthymeleaf.html#using-texts
添加thymeleaf约束（xmlns:th="http://www.thymeleaf.org"）,方便提示
<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <div th:text="${msg}"></div> </body> </html>
编写Controller
@Controller public class TestController { @GetMapping("/test") public String test(Model model){ model.addAttribute("msg","Hello Thymeleaf"); return "test"; } }
Thymeleaf 语法学习
表达式：https://www.thymeleaf.org/doc/tutorials/3.0/usingthymeleaf.html#standard-expression-syntax
Simple expressions:（表达式语法） Variable Expressions: ${...}：获取变量值；OGNL； 1）、获取对象的属性、调用方法 2）、使用内置的基本对象：#18 #ctx : the context object. #vars: the context variables. #locale : the context locale. #request : (only in Web Contexts) the HttpServletRequest object. #response : (only in Web Contexts) the HttpServletResponse object. #session : (only in Web Contexts) the HttpSession object. #servletContext : (only in Web Contexts) the ServletContext object. 3）、内置的一些工具对象： #execInfo : information about the template being processed. #uris : methods for escaping parts of URLs/URIs #conversions : methods for executing the configured conversion service (if any). #dates : methods for java.util.Date objects: formatting, component extraction, etc. #calendars : analogous to #dates , but for java.util.Calendar objects. #numbers : methods for formatting numeric objects. #strings : methods for String objects: contains, startsWith, prepending/appending, etc. #objects : methods for objects in general. #bools : methods for boolean evaluation. #arrays : methods for arrays. #lists : methods for lists. #sets : methods for sets. #maps : methods for maps. #aggregates : methods for creating aggregates on arrays or collections. ================================================================================== Selection Variable Expressions: *{...}：选择表达式：和${}在功能上是一样； Message Expressions: #{...}：获取国际化内容 Link URL Expressions: @{...}：定义URL； Fragment Expressions: ~{...}：片段引用表达式 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 ${name}| Arithmetic operations:（数学运算） Binary operators: + , - , * , / , % Minus sign (unary operator): - Boolean operations:（布尔运算） Binary operators: and , or Boolean negation (unary operator): ! , not Comparisons and equality:（比较运算） Comparators: > , < , >= , <= ( gt , lt , ge , le ) Equality operators: == , != ( eq , ne ) Conditional operators:条件运算（三元运算符） If-then: (if) ? (then) If-then-else: (if) ? (then) : (else) Default: (value) ?: (defaultvalue) Special tokens: No-Operation: _
属性设置：https://www.thymeleaf.org/doc/tutorials/3.0/usingthymeleaf.html#attribute-precedence
| Order | 特征 | Attributes | 备注 |
|---|---|---|---|
| 1 | Fragment inclusion | th:insertth:replace |
片段包含：相当于include |
| 2 | Fragment iteration | th:each |
循环 |
| 3 | Conditional evaluation | th:ifth:unlessth:switchth:case |
判断 |
| 4 | Local variable definition | th:objectth:with |
|
| 5 | General attribute modification | th:attrth:attrprependth:attrappend |
通用属性修改 |
| 6 | Specific attribute modification | th:valueth:hrefth:src... |
th:可以修饰Html的标签属性 |
| 7 | Text (tag body modification) | th:textth:utext |
不转义特殊字符 |
| 8 | Fragment specification | th:fragment |
声明片段 |
| 9 | Fragment removal | th:remove |
练习测试
1、Controller
@RequestMapping("/t2")
public String test2(Map<String,Object> map){
//存入数据
map.put("msg","<h1>Hello</h1>");
map.put("users", Arrays.asList("xiaoqiang","dahuang"));
//classpath:/templates/test.html
return "test";
}
2、html
<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <div th:text="${msg}"></div> <!--不转义--> <div th:utext="${msg}"></div> <!--遍历数据--> <!--th:each每次遍历都会生成当前这个标签：官网#9--> <h4 th:each="user :${users}" th:text="${user}"></h4> <h4> <!--行内写法：官网#12--> <span th:each="user:${users}">[[${user}]]</span> </h4> </body> </html>