Thymeleaf：工作机制

末蓝、 2024-03-22 14:13 17阅读 0赞

### 工作机制 ###

#### 初始化阶段 ####

目标：创建 TemplateEngine 对象  
封装：因为对每一个请求来说，TemplateEngine 对象使用的都是同一个，所以在初始化阶段准备好  
![在这里插入图片描述][383f6fb73fee42c5ad0f7cc9411fdd9d.png_pic_center]

#### 请求处理阶段 ####

![在这里插入图片描述][8d00f3656c8f4702bde8be07b3fc2141.png_pic_center]

#### 案例 ####

**依赖**

<dependency>
         <groupId>org.thymeleaf</groupId>
         <artifactId>thymeleaf</artifactId>
         <version>3.0.11.RELEASE</version>
     </dependency>

**代码**

import org.thymeleaf.TemplateEngine;
    import org.thymeleaf.context.WebContext;
    import org.thymeleaf.templatemode.TemplateMode;
    import org.thymeleaf.templateresolver.ServletContextTemplateResolver;
    
    import javax.servlet.ServletContext;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    /**
     * 处理视图模板文件的 Servlet 基类
     */
    public class ViewBaseServlet extends HttpServlet {
        
    
        private TemplateEngine templateEngine;
    
        /**
         * 初始化
         * @throws ServletException
         */
        @Override
        public void init() throws ServletException {
        
    
            // 1.获取ServletContext对象
            ServletContext servletContext = this.getServletContext();
    
            // 2.创建Thymeleaf解析器对象
            ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(servletContext);
    
            // 3.给解析器对象设置参数
            // ①HTML是默认模式，明确设置是为了代码更容易理解
            templateResolver.setTemplateMode(TemplateMode.HTML);
    
            // ②设置前缀
            String viewPrefix = servletContext.getInitParameter("view-prefix");
    
            templateResolver.setPrefix(viewPrefix);
    
            // ③设置后缀
            String viewSuffix = servletContext.getInitParameter("view-suffix");
    
            templateResolver.setSuffix(viewSuffix);
    
            // ④设置缓存过期时间（毫秒）
            templateResolver.setCacheTTLMs(60000L);
    
            // ⑤设置是否缓存
            templateResolver.setCacheable(true);
    
            // ⑥设置服务器端编码方式
            templateResolver.setCharacterEncoding("utf-8");
    
            // 4.创建模板引擎对象
            templateEngine = new TemplateEngine();
    
            // 5.给模板引擎对象设置模板解析器
            templateEngine.setTemplateResolver(templateResolver);
    
        }
    
        /**
         * 请求处理
         * @param templateName
         * @param req
         * @param resp
         * @throws IOException
         */
        protected void processTemplate(String templateName, HttpServletRequest req, HttpServletResponse resp) throws IOException {
        
            // 1.设置响应体内容类型和字符集
            resp.setContentType("text/html;charset=UTF-8");
    
            // 2.创建WebContext对象
            WebContext webContext = new WebContext(req, resp, getServletContext());
    
            // 3.处理模板数据
            templateEngine.process(templateName, webContext, resp.getWriter());
        }
    }

**配置web.xml**

<?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns="http://java.sun.com/xml/ns/javaee"
               xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
               xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
    		  http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
               version="2.5">
        
        
        
        <context-param>
            <param-name>view-prefix</param-name>
            <param-value>/WEB-INF/pages/</param-value>
        </context-param>
        <context-param>
            <param-name>view-suffix</param-name>
            <param-value>.html</param-value>
        </context-param>
    </web-app>

[383f6fb73fee42c5ad0f7cc9411fdd9d.png_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/22/36f05e4f87054d7eb5e108b6e69d381e.png
[8d00f3656c8f4702bde8be07b3fc2141.png_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/22/8bca21ce2553407297b4265f9221a816.png