初识SpringBoot-第四篇:整合thymeleaf & 国际化配置
模板引擎(这里特指用于Web开发的模板引擎)是为了使用户界面与业务数据(内容)分离而产生的,它可以生成特定格式的文档,用于网站的模板引擎就会生成一个标准的HTML文档。
目前使用广泛的模板引擎有JSP、Velocity、Freemarker、Thymeleaf等。。SpringBoot推荐使用的分别如下图所示 thymeleaf、freemark、groovy…
下面我就介绍其中thymeleaf的相关整合
引入thymeleaf
在pom文件中引入
<!-- 引入 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
2.1.6
</dependency>
<!-- 切换thymeleaf版本 -->
<properties>
<thymeleaf.version>3.0.9.RELEASE</thymeleaf.version>
<!-- 布局功能的支持程序 thymeleaf3主程序 layout2以上版本 -->
<!-- thymeleaf2 layout1-->
<thymeleaf-layout-dialect.version>2.2.2</thymeleaf-layout-dialect.version>
</properties>
or
<!-- 布局功能的支持程序 thymeleaf3主程序 layout2以上版本 -->
<thymeleaf-spring5.version>3.0.9.RELEASE</thymeleaf-spring5.version>
<thymeleaf-layout-dialect.version>2.2.2</thymeleaf-layoutdialect.version>
Thymeleaf使用
在springboot中默认为thymeleaf配置了相关配置
@ConfigurationProperties(prefix = "spring.thymeleaf")
public class ThymeleafProperties {
//默认编码
private static final Charset DEFAULT_ENCODING = Charset.forName("UTF-8");
//文本类型
private static final MimeType DEFAULT_CONTENT_TYPE = MimeType.valueOf("text/html");
//加载地址
public static final String DEFAULT_PREFIX = "classpath:/templates/";
//默认后缀
public static final String DEFAULT_SUFFIX = ".html";
有了上方默认配置,只要我们把HTML页面放在classpath:/templates/,thymeleaf就能自动渲染;
1、使用
1、在html文件中导入thymeleaf的名称空间
<!-- 引入该名称空间 加入代码提示及规范 -->
<html lang="en" xmlns:th="http://www.thymeleaf.org">
2、使用thymeleaf语法
接口:
@RequestMapping(value = "/success")
public String success(Map<String,Object> map){
map.put("hello","<h1>success</h1>");
map.put("users", Arrays.asList("zhangsan","lisi","wangwu"));
return "success";
}
success.html
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<h1>Success!!</h1>
<hr/>
<!-- th:text 将div里面的文本内容设置为变量值 ,不转义特殊字符
th:utext 将div里面的文本内容设置为变量值 ,转义特殊字符
th:id 将div的id值设为该变量
th:class 将div的class属性设置为该变量
-->
<div th:text="${hello}" th:id="${hello}" th:class="${hello}"></div>
<div th:utext="${hello}" th:id="${hello}" th:class="${hello}"></div>
<hr>
<!-- th:each 每次比遍历都会生成一个新的标签 -->
<!--:3个h4标签-->
<h4 th:text="${user}" th:each="user : ${users}"></h4>
<hr>
<h4>
<!--:3个span标签-->
<span th:text="${user}" th:each="user : ${users}"></span>
</h4>
</body>
</html>
浏览器访问结果:
2、语法规则
1)、th:text;改变当前元素里面的文本内容;
th:任意html属性;来替换原生属性的值
2)、表达式?
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:
#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;
补充:配合 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: _
3、优化配置
模板热部署
在 IntelliJ IDEA
中使用 thymeleaf
模板的时候,发现每次修改静态页面都需要重启才生效,这点是很不友好的,百度了下发现原来是默认配置搞的鬼,为了提高响应速度,默认情况下会缓存模板。如果是在开发中请将spring.thymeleaf.cache 属性设置成 false。在每次修改静态内容时按Ctrl+Shift+F9即可重新加载了…
application配置项
国际化配置
-
编写国际化配置文件;
-
使用ResourceBundleMessageSource管理国际化资源文件
-
在页面使用fmt:message取出国际化内容
同样的 ,springboot也已经为我们配置好了挂你国际化资源文件的组件
如下为SpringBoot的自动配置文件部分代码:
@ConfigurationProperties(prefix = "spring.messages") //代表我们在application 文件配置此相关配置的前缀
public class MessageSourceAutoConfiguration {
/**
* Comma-separated list of basenames (essentially a fully-qualified classpath
* location), each following the ResourceBundle convention with relaxed support for
* slash based locations. If it doesn't contain a package qualifier (such as
* "org.mypackage"), it will be resolved from the classpath root.
*/
private String basename = "messages";
//我们的配置文件可以直接放在类路径下叫messages.properties;
@Bean
public MessageSource messageSource() {
ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
if (StringUtils.hasText(this.basename)) {
//设置国际化资源文件的基础名(去掉语言国家代码的)
messageSource.setBasenames(StringUtils.commaDelimitedListToStringArray(
StringUtils.trimAllWhitespace(this.basename)));
}
if (this.encoding != null) {
//配置默认编码
messageSource.setDefaultEncoding(this.encoding.name());
}
messageSource.setFallbackToSystemLocale(this.fallbackToSystemLocale);
messageSource.setCacheSeconds(this.cacheSeconds);
messageSource.setAlwaysUseMessageFormat(this.alwaysUseMessageFormat);
return messageSource;
}
1、编写国际化配置文件,抽取页面需要显示的国际化消息
首先创建一个存放国际化配置文件的文件夹,其中配置文件名中只需要包含国际化编码信息(如:en_US、zh_CN等…) idea则会自动帮我们建立国际化视图
2、文本配置
springboot相关配置文件配置
application.properties
#springboot已经为我们配置好了默认配置 如下只是示例
spring.messages.basename=i18n.login
spring.messages.always-use-message-format=false
spring.messages.encoding=utf-8
3、在html中使用thymeleaf获取国际化配置的值
index.html
<!-- 引入格式 #{besename.value} 如#{login.tip} -->
<h1 class="h3 mb-3 font-weight-normal" th:text="#{login.tip}">Please sign in</h1>
<p style="color: red;" th:text="${msg}" th:if="${not #strings.isEmpty(msg)}"></p>
<label class="sr-only" th:text="#{login.username}">Username</label>
<input type="text" name="username" class="form-control" placeholder="Username" th:placeholder="#{login.username}" required="" autofocus="">
<label class="sr-only" th:text="#{login.password}">Password</label>
<input type="password" name="password" class="form-control" placeholder="Password" required="" th:placeholder="#{login.password}" >
<div class="checkbox mb-3">
<label>
<input type="checkbox" value="remember-me" />[[#{login.remember}]]
</label>
</div>
<button class="btn btn-lg btn-primary btn-block" type="submit" th:text="#{login.btn}">Sign in</button>
<p class="mt-5 mb-3 text-muted">© 2017-2018</p>
<!-- 简单例子 切换请求-->
<a class="btn btn-sm" th:href="@{/index.html(l='zn_CN')}">中文</a>
<a class="btn btn-sm" th:href="@{/index.html(l='en_US')}">English</a>
</form>
IndexController 文件映射controller层
@Controller
public class IndexController {
@RequestMapping(value = {"/","/index"})
public String Index(){
return "index";
}
自定义国际化配置类
package com.shawn.chapter4.component;
public class MyLocaleResolver implements LocaleResolver {
@Override
public Locale resolveLocale(HttpServletRequest httpServletRequest) {
String l = httpServletRequest.getParameter("l");
Locale locale = Locale.getDefault();
if(!StringUtils.isEmpty(l)){
String[] s = l.split("_");
locale = new Locale(s[0],s[1]);
}
return locale;
}
将自定义配置类加入bean容器中
MyMvcConfig 自定义配置类
package com.shawn.chapter4.config;
@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
...
@Bean
public LocaleResolver localeResolver(){
return new MyLocaleResolver();
}
}
如此国际化配置就配置完成了
配置原理:
spring boot在会在启动时加载所有国际化配置类
WebMvcAutoConfiguration web相关自动配置类(后续文章会详细描述):
@Configuration
@ConditionalOnWebApplication(
type = Type.SERVLET
)
@ConditionalOnClass({Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class})
@ConditionalOnMissingBean({WebMvcConfigurationSupport.class})
@AutoConfigureOrder(-2147483638)
@AutoConfigureAfter({DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class, ValidationAutoConfiguration.class})
public class WebMvcAutoConfiguration {
@Bean
@ConditionalOnMissingBean
@ConditionalOnProperty(
prefix = "spring.mvc",
name = {"locale"}
)
//国际化相关配置内容
public LocaleResolver localeResolver() {
if (this.mvcProperties.getLocaleResolver() == org.springframework.boot.autoconfigure.web.servlet.WebMvcProperties.LocaleResolver.FIXED) {
return new FixedLocaleResolver(this.mvcProperties.getLocale());
} else {
AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver();
localeResolver.setDefaultLocale(this.mvcProperties.getLocale());
return localeResolver;
}
}
}
//如上所示 只需要实现LocaleResolver接口即可表明这是一个国际化配置容器
public class AcceptHeaderLocaleResolver implements LocaleResolver {
}