SpringBoot系列——Thymeleaf模板

  前言

  thymeleaf是springboot官方推荐使用的java模板引擎,在springboot的参考指南里的第28.1.10 Template Engines中介绍并推荐使用thymeleaf,建议我们应该避免使用jsp,jsp的本质是一个java的servlet类,jsp引擎将jsp的内容编译成.class,"out.write"输出到response再响应到浏览器,虽然java是一次编译,到处运行,但也大大增加了服务器压力,而且jsp将后台java语言嵌入页面,还要放入服务容器才能打开,前后端不分离,严重增加了前端工程师的开发工作、效率。

  thymeleaf官网对thymeleaf的介绍:

  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.

 

  thymeleaf使用教程,骚操作:鼠标右键,翻译成简体中文再看。

  thymeleaf使用th属性赋予每个标签与后台交互的能力,当html文件在本地直接用浏览器打开,浏览器引擎会忽略掉th属性,并正常渲染页面,当把html文件放到服务容器访问,th属性与后台交互,获取数据替换原先的内容,这样前端工程师在编写html页面时,在本地开发,正常实现页面逻辑效果即可,数据先写死,当放到服务容器时数据从后台获取。

 

  spring对thymeleaf的配置,来自springboot参考手册,Common application properties:https://docs.spring.io/spring-boot/docs/2.1.0.RELEASE/reference/htmlsingle/#common-application-properties

# THYMELEAF (ThymeleafAutoConfiguration)
spring.thymeleaf.cache=true # Whether to enable template caching.
spring.thymeleaf.check-template=true # Whether to check that the template exists before rendering it.
spring.thymeleaf.check-template-location=true # Whether to check that the templates location exists.
spring.thymeleaf.enabled=true # Whether to enable Thymeleaf view resolution for Web frameworks.
spring.thymeleaf.enable-spring-el-compiler=false # Enable the SpringEL compiler in SpringEL expressions.
spring.thymeleaf.encoding=UTF-8 # Template files encoding.
spring.thymeleaf.excluded-view-names= # Comma-separated list of view names (patterns allowed) that should be excluded from resolution.
spring.thymeleaf.mode=HTML # Template mode to be applied to templates. See also Thymeleaf's TemplateMode enum.
spring.thymeleaf.prefix=classpath:/templates/ # Prefix that gets prepended to view names when building a URL.
spring.thymeleaf.reactive.chunked-mode-view-names= # Comma-separated list of view names (patterns allowed) that should be the only ones executed in CHUNKED mode when a max chunk size is set.
spring.thymeleaf.reactive.full-mode-view-names= # Comma-separated list of view names (patterns allowed) that should be executed in FULL mode even if a max chunk size is set.
spring.thymeleaf.reactive.max-chunk-size=0B # Maximum size of data buffers used for writing to the response.
spring.thymeleaf.reactive.media-types= # Media types supported by the view technology.
spring.thymeleaf.render-hidden-markers-before-checkboxes=false # Whether hidden form inputs acting as markers for checkboxes should be rendered before the checkbox element itself.
spring.thymeleaf.servlet.content-type=text/html # Content-Type value written to HTTP responses.
spring.thymeleaf.servlet.produce-partial-output-while-processing=true # Whether Thymeleaf should start writing partial output as soon as possible or buffer until template processing is finished.
spring.thymeleaf.suffix=.html # Suffix that gets appended to view names when building a URL.
spring.thymeleaf.template-resolver-order= # Order of the template resolver in the chain.
spring.thymeleaf.view-names= # Comma-separated list of view names (patterns allowed) that can be resolved.

 

  使用

  maven引入依赖

        <!--Thymeleaf模板依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

 

  项目结构

  thymeleaf默认,页面跳转默认路径:src/main/resources/templates,静态资源默认路径:src/main/resources/static;

   

 

  yml配置文件

  我们也可以再配置文件中修改它:classpath:/view/

 

   controller页面跳转

  使用ModelAndView进行跳转,将数据add进去

    @RequestMapping("/login.do")
    public ModelAndView login(User user){
        Result result=userService.login(user);
        ModelAndView mv=new ModelAndView();
        mv.addObject("newText","你好,Thymeleaf!");
        mv.addObject("gender","1");
        mv.addObject("userList",result.getData());
        if(result.getData()!=null) {
            mv.addObject("loginUser",result.getData());
        }
        mv.setViewName("index.html");
        return mv;
    }

 

  html页面取值

  引入命名空间,避免校验错误<html xmlns:th="http://www.thymeleaf.org">

<!DOCTYPE html>
<!--解决idea thymeleaf 表达式模板报红波浪线-->
<!--suppress ALL -->
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8" />
    <title>srpingboot</title>
</head>
<body>
    <!-- 属性替换,其他属性同理 -->
    <h1 th:text="${newText}">Hello World</h1>
    <!--
        设置多个attr
        th:attr="id=${user.id},data-xxx=${user.xxx},data-yyy=${user.yyy}"

        片段的使用、传值和调用
        <div th:fragment="common(text1,text2)">
            ...
        </div>
        th:insert 是最简单的:它只是插入指定的片段作为其主机标签的主体。
        <div th:insert="base ::common(${text1},${text2})"></div>

        th:replace实际上用指定的片段替换它的主机标签。
        <div th:replace="base ::common(${text1},${text2})"></div>
    
     三目表达式:
     <h3 th:text="${loginUser != null} ? ${loginUser.username} : '请登录'"></h3> 
--> <!-- if-else --> <h3 th:if="${loginUser} ne null" th:text="${loginUser.username}"></h3> <h3 th:unless="${loginUser} ne null">请登录</h3> <!-- switch --> <div th:switch="${gender}"> <p th:case="'1'"></p> <p th:case="'0'"></p> <!-- th:case="*" 类似switch中的default --> <p th:case="*">其他</p> </div> <!--
    each
    其中,iterStat参数为状态变量,常用的属性有
    index 迭代下标,从0开始
    count 迭代下标,从1开始
    size 迭代元素的总量
    current 当前元素
   -->
    <table>
        <thead>
            <tr>
                <th>id</th>
                <th>username</th>
                <th>password</th>
                <th>created</th>
                <th>description</th>
            </tr>
        </thead>
        <tbody>
            <tr th:each="user,iterStat : ${userList}">
                <td th:text="${user.id}"></td>
                <td th:text="${user.username}"></td>
                <td th:text="${user.password}"></td>
                <td th:text="${user.created}"></td>
                <td th:text="${user.description}"></td>
            </tr>
        </tbody>
    </table>
</body>
<!-- 引入静态资源 -->
<script th:src="@{/js/jquery-1.9.1.min.js}" type="application/javascript"></script>
</html>

 

  本地打开

 

  服务容器打开,登录失败页面效果

   

  服务容器打开,登录成功页面效果

 

  标准表达式

  简单表达
  变量表达式: ${...}
  选择变量表达式: *{...}
  消息表达式: #{...}
  链接网址表达式: @{...}
  片段表达式: ~{...}

  字面
  文本文字:'one text','Another one!',...
  号码文字:0,34,3.0,12.3,...
  布尔文字:true,false
  空字面: null
  文字标记:one,sometext,main,...
  文字操作:
  字符串连接: +
  文字替换: |The name is ${name}|

  算术运算
  二元运算符:+,-,*,/,%
  减号(一元运算符): -

  布尔运算
  二元运算符:and,or
  布尔否定(一元运算符): !,not

  比较和平等
  比较:>,<,>=,<=(gt,lt,ge,le)
  等值运算符:==,!=(eq,ne)

  条件运算符
  if-then: (if) ? (then)
  if-then-else: (if) ? (then) : (else)
  default: (value) ?: (defaultvalue)

  特殊特征符
  无操作: _

  所有这些功能都可以组合和嵌套,例:
  'User is of type ' + (${user.isAdmin()} ? 'Administrator' : (${user.type} ?: 'Unknown'))

  官网表达式介绍:https://www.thymeleaf.org/doc/tutorials/3.0/usingthymeleaf.html#standard-expression-syntax

  

  后记

  springboot+thymeleaf,前后端分离已经成为了趋势,这里进行学习记录整理,以免以后又要到处查资料。

 

  补充

  2019-07-24补充:除此之外,thymeleaf还内置了很多对象,可以从上下文获取数据,还有好多对象的操作方法,具体请看:

  附录A:表达式基本对象:https://www.thymeleaf.org/doc/tutorials/3.0/usingthymeleaf.html#appendix-a-expression-basic-objects

  附录B:表达式实用程序对象:https://www.thymeleaf.org/doc/tutorials/3.0/usingthymeleaf.html#appendix-b-expression-utility-objects

  

  比如:

  在页面获取项目路径

<script th:inline="javascript">
    //项目根路径
    // ctx = /*[[@{/}]]*/'';
    ctx = [[${#request.getContextPath()}]];//应用路径
</script>

 

   判断集合长度

<p th:if="${#lists.size(list)} < 25">
    <p>list集合长度小于25!</p>
</p>

  字符串全大写、小写

<p th:text="${#strings.toUpperCase(name)}"></p>

<p th:text="${#strings.toLowerCase(name)}"></p>

  有一点要注意,使用这些内置对象,方法传参里面不需要再用${}来取值了,例如,后台传过来的名称叫name

  错误使用:

<p th:text="${#strings.toUpperCase($(name))}"></p>

  正确使用:

<p th:text="${#strings.toUpperCase(name)}"></p>

 

  更多内置对象方法请看官网!

 

  补充:本地环境不报错,Linux环境下报错,模板不存在:Error resolving template [/bam/login], template might not exist or might not be accessible by any of the configured Template Resolvers

  解决:

  把/去掉就可以了

 

  2021-04-30更新

  Thymeleaf如何实现递归?例子:菜单递归

  递归模板定义

 

<!-- 递归用户系统菜单模板 -->
<th:block th:fragment="sysMenu(menuList)">
    <dd class="layui-nav-item" th:each="menu,iterStat : ${menuList}">
        <a th:text="${menu.menuName}"
           th:data-url="${#request.getContextPath() + menu.menuPath}"
           th:data-id="${menu.menuId}" class="huanzi-menu" href="javascript:;">XXX菜单</a>
        <dl class="layui-nav-child" th:if="${#lists.size(menu.children)} > 0">
            <th:block th:include="this::sysMenu(${menu.children})"></th:block>
        </dl>
    </dd>
</th:block>

  后端数据结构(精简了数据仅保留基本结构)

[
	{“menuName”:”系统管理”,”children”:[
		{“menuName”:"系统设置",”children”:[]},
		{“menuName”:"权限管理",”children”:[]},
		{“menuName”:"菜单管理",”children”:[]},
		{“menuName”:"用户管理",”children”:[]},
		{“menuName”:"实时监控",”children”:[]},
		{“menuName”:"实时日志",”children”:[]},
		{“menuName”:"新增测试",”children”:[
			{“menuName”:"三级菜单",”children”:[]},
			{“menuName”:"三级1",”children”:[]},
			{“menuName”:"三级2",”children”:[]},
		]},
	]},
	{“menuName”:"XXX菜单",”children”:[]},
	{“menuName”:”YYY菜单”,”children”:[]},
]

  代码使用

<ul class="layui-nav layui-nav-tree" lay-filter="test" lay-shrink="all" th:style="${' background-color:' + sys.sysColor + ' !important;'}">
    <!-- 动态读取加载系统菜单 -->
    <li class="layui-nav-item" th:each="menu,iterStat : ${menuList}">
        <a th:text="${menu.menuName}"
           th:data-url="${#request.getContextPath() + menu.menuPath}"
           th:data-id="${menu.menuId}" class="huanzi-menu" href="javascript:;">XXX菜单</a>
        <dl class="layui-nav-child" th:if="${#lists.size(menu.children)} > 0">
            <th:block th:include="common/head::sysMenu(${menu.children})"></th:block>
        </dl>
    </li>
</ul>

  页面效果

 

  代码开源

  代码已经开源、托管到我的GitHub、码云:

  GitHub:https://github.com/huanzi-qch/springBoot

  码云:https://gitee.com/huanzi-qch/springBoot

posted @ 2018-11-08 17:24  huanzi-qch  阅读(13024)  评论(0编辑  收藏  举报