SpringBootWeb开发-4

lamirs2023年1月22日大约 3 分钟

上一级页面：ssm-spring-boot速成学习索引

前言

43、视图解析-Thymeleaf初体验

Thymeleaf is a modern server-side Java template engine for both web and standalone environments.
Thymeleaf's main goal is to bring elegant natural templates to your development workflow — HTML that can be correctly displayed in browsers and also work as static prototypes, allowing for stronger collaboration in development teams.
With modules for Spring Framework, a host of integrations with your favourite tools, and the ability to plug in your own functionality, Thymeleaf is ideal for modern-day HTML5 JVM web development — although there is much more it can do.——Link

Thymeleaf官方文档

thymeleaf使用

引入Starter

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

自动配置好了thymeleaf

@Configuration(proxyBeanMethods = false)
@EnableConfigurationProperties(ThymeleafProperties.class)
@ConditionalOnClass({ TemplateMode.class, SpringTemplateEngine.class })
@AutoConfigureAfter({ WebMvcAutoConfiguration.class, WebFluxAutoConfiguration.class })
public class ThymeleafAutoConfiguration {
    ...
}

自动配好的策略

所有thymeleaf的配置值都在 ThymeleafProperties
配置好了 SpringTemplateEngine
配好了 ThymeleafViewResolver
我们只需要直接开发页面

public static final String DEFAULT_PREFIX = "classpath:/templates/";//模板放置处
public static final String DEFAULT_SUFFIX = ".html";//文件的后缀名

编写一个控制层：

@Controller
public class ViewTestController {
    @GetMapping("/hello")
    public String hello(Model model){
        //model中的数据会被放在请求域中 request.setAttribute("a",aa)
        model.addAttribute("msg","一定要大力发展工业文化");
        model.addAttribute("link","http://www.baidu.com");
        return "success";
    }
}

/templates/success.html：

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1 th:text="${msg}">nice</h1>
<h2>
    <a href="www.baidu.com" th:href="${link}">去百度</a>  <br/>
    <a href="www.google.com" th:href="@{/link}">去百度</a>
</h2>
</body>
</html>

server:
  servlet:
    context-path: /app #设置应用名

这个设置后，URL要插入/app, 如http://localhost:8080/app/hello.html。

基本语法

表达式

表达式名字	语法	用途
变量取值	`${…}`	获取请求域、session域、对象等值
选择变量	`*{…}`	获取上下文对象值
消息	`#{…}`	获取国际化等值
链接	`@{…}`	生成链接
片段表达式	`~{…}`	jsp:include 作用，引入公共页面片段

字面量

文本值: 'one text' , 'Another one!' ,…
数字: 0 , 34 , 3.0 , 12.3 ,…
布尔值: true , false
空值: null
变量： one，two，…. 变量不能有空格

文本操作

字符串拼接: +
变量替换: |The name is ${name}|

数学运算

运算符: + , - , * , / , %

布尔运算

运算符: and , or
一元运算: ! , not

比较运算

比较: > , < , >= , <= ( gt , lt , ge , le )
等式: == , != ( eq , ne )

条件运算

If-then: (if) ? (then)
If-then-else: (if) ? (then) : (else)
Default: (value) ?: (defaultvalue)

特殊操作

无操作： _

设置属性值-th:attr

设置单个值

<form action="subscribe.html" th:attr="action=@{/subscribe}">
  <fieldset>
    <input type="text" name="email" />
    <input type="submit" value="Subscribe!" th:attr="value=#{subscribe.submit}"/>
  </fieldset>
</form>

设置多个值

<img src="../../images/gtvglogo.png"  
     th:attr="src=@{/images/gtvglogo.png},title=#{logo},alt=#{logo}" />

官方文档 - 5 Setting Attribute Values

迭代

<tr th:each="prod : ${prods}">
    <td th:text="${prod.name}">Onions</td>
    <td th:text="${prod.price}">2.41</td>
    <td th:text="${prod.inStock}? #{true} : #{false}">yes</td>
</tr>

<tr th:each="prod,iterStat : ${prods}" th:class="${iterStat.odd}? 'odd'">
    <td th:text="${prod.name}">Onions</td>
    <td th:text="${prod.price}">2.41</td>
    <td th:text="${prod.inStock}? #{true} : #{false}">yes</td>
</tr>

条件运算

<a href="comments.html"
	th:href="@{/product/comments(prodId=${prod.id})}"
	th:if="${not #lists.isEmpty(prod.comments)}">view</a>

<div th:switch="${user.role}">
      <p th:case="'admin'">User is an administrator</p>
      <p th:case="#{roles.manager}">User is a manager</p>
      <p th:case="*">User is some other thing</p>
</div>

属性优先级

Order	Feature	Attributes
1	Fragment inclusion	`th:insert` `th:replace`
2	Fragment iteration	`th:each`
3	Conditional evaluation	`th:if` `th:unless` `th:switch` `th:case`
4	Local variable definition	`th:object` `th:with`
5	General attribute modification	`th:attr` `th:attrprepend` `th:attrappend`
6	Specific attribute modification	`th:value` `th:href` `th:src` `…`
7	Text (tag body modification)	`th:text` `th:utext`
8	Fragment specification	`th:fragment`
9	Fragment removal	`th:remove`

官方文档 - 10 Attribute Precedence

SpringBootWeb开发-5

spring-boot-web-开发-5