SpringBoot学习笔记 (17)

找到对应的pom依赖:可以适当点进源码看下本来的包!

<!--thymeleaf--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency>

Maven会自动下载jar包,我们可以去看下下载的东西;

image-20210131131243997

12.1、Thymeleaf分析

前面呢,我们已经引入了Thymeleaf,那这个要怎么使用呢?

我们首先得按照SpringBoot的自动配置原理看一下我们这个Thymeleaf的自动配置规则,在按照那个规则,我们进行使用。

我们去找一下Thymeleaf的自动配置类:ThymeleafProperties

@ConfigurationProperties( prefix = "spring.thymeleaf" ) public class ThymeleafProperties { private static final Charset DEFAULT_ENCODING; public static final String DEFAULT_PREFIX = "classpath:/templates/"; public static final String DEFAULT_SUFFIX = ".html"; private boolean checkTemplate = true; private boolean checkTemplateLocation = true; private String prefix = "classpath:/templates/"; private String suffix = ".html"; private String mode = "HTML"; private Charset encoding; }

我们可以在其中看到默认的前缀和后缀!

我们只需要把我们的html页面放在类路径下的templates下,thymeleaf就可以帮我们自动渲染了。

使用thymeleaf什么都不需要配置,只需要将他放在指定的文件夹下即可!

测试

1、编写一个TestController

@Controller public class TestController { @RequestMapping("/t1") public String test1(){ //classpath:/templates/test.html return "test"; } }

2、编写一个测试页面 test.html 放在 templates 目录下

<!DOCTYPE html> <html lang="en"> <head> <title>Title</title> </head> <body> <h1>测试页面</h1> </body> </html>

3、启动项目请求测试

12.2、Thymeleaf 语法学习

要学习语法,还是参考官网文档最为准确,我们找到对应的版本看一下;

Thymeleaf 官网:https://www.thymeleaf.org/ , 简单看一下官网!我们去下载Thymeleaf的官方文档!

我们做个最简单的练习 :我们需要查出一些数据,在页面中展示

1、修改测试请求,增加数据传输;

@RequestMapping("/t1") public String test1(Model model){ //存入数据 model.addAttribute("msg","Hello,Thymeleaf"); //classpath:/templates/test.html return "test"; }

2、我们要使用thymeleaf,需要在html文件中导入命名空间的约束,方便提示。

我们可以去官方文档的#3中看一下命名空间拿来过来:

xmlns:th="http://www.thymeleaf.org"

3、我们去编写下前端页面

<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <title>狂神说</title> </head> <body> <h1>测试页面</h1> <!--th:text就是将div中的内容设置为它指定的值,和之前学习的Vue一样--> <div th:text="${msg}"></div> </body> </html>

4、启动测试!

image-20210131131603064

OK,入门搞定,我们来认真研习一下Thymeleaf的使用语法!

1、我们可以使用任意的 th:attr 来替换Html中原生属性的值!

image-20210131131617402

2、我们能写哪些表达式呢?

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: _

练习测试:

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