今天使用thymeleaf layout布局时总是不生效，特此把解决问题的步骤和几个关键点记录下来备忘。
一、检查依赖
1.thymeleaf必备maven依赖：
<dependency>
<groupId>org.thymeleaf</groupId>
<artifactId>thymeleaf</artifactId>
<version>${thymeleaf.version}</version>
</dependency>
<dependency>
<groupId>org.thymeleaf</groupId>
<artifactId>thymeleaf-spring4</artifactId>
<version>${thymeleaf.version}</version>
</dependency>
2.如果使用layout布局，还需要添加：
<dependency>
<groupId>nz.net.ultraq.thymeleaf</groupId>
<artifactId>thymeleaf-layout-dialect</artifactId>
<version>2.2.2</version>
</dependency>
二、配置视图引擎
1.配置thymeleaf作为视图引擎
<!-- Thymeleaf View Resolver - implementation of Spring's ViewResolver interface -->
<bean id="viewResolver" class="org.thymeleaf.spring4.view.ThymeleafViewResolver">
<property name="templateEngine" ref="templateEngine" />
<property name="characterEncoding" value="UTF-8" />
</bean>
<!-- Thymeleaf Template Engine (Spring4-specific version) -->
<bean id="templateEngine" class="org.thymeleaf.spring4.SpringTemplateEngine">
<property name="templateResolvers">
<set>
<ref bean="templateResolver" />
</set>
</property>
</bean>
<!-- Thymeleaf Template Resolver -->
<bean id="templateResolver" class="org.thymeleaf.spring4.templateresolver.SpringResourceTemplateResolver">
<property name="prefix" value="/WEB-INF/templates/" />
<property name="templateMode" value="HTML" />
<property name="suffix" value=".html"></property>
<property name="characterEncoding" value="UTF-8"></property>
</bean>
2.使用layout还需要在templateEngine添加如下节点：
<bean id="templateEngine" class="org.thymeleaf.spring4.SpringTemplateEngine">
……
<property name="additionalDialects">
<set>
<bean class="nz.net.ultraq.thymeleaf.LayoutDialect"/>
</set>
</property>
</bean>
三、页面
task/layout.html
<!DOCTYPE html>
<html lang="en" xmlns:layout="http://www.thymeleaf.org">
<head>
<meta charset="utf-8">
<title>mysite</title>
</head>
<body>
<div class="container">
<div class="row">
<div class="span3" th:insert="fragments/menu::menu"></div>
<div class="span9" layout:fragment="content"></div>
</div>
</div>
</body>
</html>
index.html
<!DOCTYPE html>
<html lang="en" layout:decorator="task/layout">
<head>
<meta charset="utf-8">
<title>index</title>
</head>
<body>
<div layout:fragment="content">
<h1>
Welcome!
</h1>
</div>
</body>
</html>
三、版本号
如果检查了以上几项还是没问题，最后还有一点值得注意的，就是thymeleaf和thymeleaf-layout-dialect的版本。
我最后就是调整了maven依赖的版本号，终于成功了。