Day-06 thymeleaf和三层模型

01-mvc模型(掌握)02-thymeleaf概述(掌握)03-物理视图和逻辑视图(掌握)04-thymeleaf入门(掌握)05-thymeleaf修改标签内容(掌握)06-thymeleaf修改标签属性(掌握)07-thymeleaf解析url(掌握)08-thymeleaf操作域对象(掌握)09-OGNL表达式(掌握)10-OGNL使用(掌握)11-thymeleaf条件渲染(掌握)

为什么？

现在，会在java代码编写html代码用于渲染页面，这明显不合理；但是，也无法在html文件中使用java代码中的数据。 mvc模型

C : controller,控制器 , java程序

①处理请求②调度页面 M : model,模型 , java数据(javabean、基本类型、String…)

①封装数据 V : view , 视图 , html程序

①渲染页面 将模型渲染视图使用thymeleaf技术。 02-thymeleaf概述(掌握)

概述

Thymeleaf是一款用于渲染XML/XHTML/HTML5内容的模板引擎。类似JSP，Velocity，FreeMaker 等， 它也可以轻易的与Spring MVC等Web框架进行集成作为Web应用的模板引擎。它的主要作用 是在静态页面上渲染显示动态数据 特点

SpringBoot官方推荐使用的视图模板技术，和SpringBoot完美整合。 03-物理视图和逻辑视图(掌握)

概述

物理视图：请求转发到一个资源时使用的绝对路径逻辑视图：物理视图=视图前缀+逻辑视图+视图后缀

视图前缀：物理视图中最大的公共前缀视图后缀：物理视图中最大的公共后缀（后缀名） 举例

04-thymeleaf入门(掌握)

开发步骤

①引入thymeleaf的相关jar包②编写web.xml

配置视图前缀配置视图后缀 ③定义ViewbaseServlet类④定义Servlet类继承ViewbaseServlet类⑤编写html页面

使用thymeleaf渲染页面

①引入thymeleaf的相关jar包

②编写web.xml

    view-prefix
    /pages/




    view-suffix
    .html

③定义ViewbaseServlet类

public class ViewbaseServlet extends HttpServlet {
    private TemplateEngine templateEngine;

    @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);

    }


    
    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());
    }
}

④定义Servlet类继承ViewbaseServlet类

@WebServlet("/demo01")
public class Demo01Servlet extends ViewbaseServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String errorMsg = "用户名已经存在!";
        req.setAttribute("errorMsg", errorMsg);
        //转发到demo01.html
        processTemplate("demo01", req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

⑤编写html页面

注意事项

如果要使用thymeleaf指令，必须要通过ViewbaseServlet 05-thymeleaf修改标签内容(掌握)

概述

使用th:text指令修改标签内容

代码实现

@WebServlet("/demo02")
public class Demo02Servlet extends ViewbaseServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String msg = "helloworld";
        request.setAttribute("msg", msg);
        processTemplate("demo02", request, response);

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

概述

使用"th:属性"修改标签的属性值

代码实现

@WebServlet("/demo03")
public class Demo03Servlet extends ViewbaseServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String msg = "helloworld";
        request.setAttribute("msg", msg);
        processTemplate("demo03", request, response);

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

    
    




超链接

代码实现1 : 不带请求参数

    
    

    



请求Demo04Servlet

请求Demo04Servlet

代码实现2 : 携带请求参数

    
    

    



请求Demo04Servlet
请求Demo04Servlet

域对象

ServletRequestHttpSessionServletContext

代码实现

@WebServlet("/demo06")
public class Demo06Servlet extends ViewbaseServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //当前请求有效
        request.setAttribute("msg1","request");
        //当前会话有效
        request.getSession().setAttribute("msg2","session");
        //当前项目有效
        getServletContext().setAttribute("msg3","servletContext");
        processTemplate("demo06",request,response);

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

概述

OGNL : Object-Graph Navigation Language : 对象-图导航语言 OGNL

10-OGNL使用(掌握)

代码实现

@WebServlet("/demo07")
public class Demo07Servlet extends ViewbaseServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Student student = new Student();

        student.setStudentName("樊育东");


        student.setSubject(new Subject("java"));

        List schoolList = new ArrayList<>();
        schoolList.add(new School("尚大幼儿园"));
        schoolList.add(new School("尚大小学"));
        schoolList.add(new School("尚大中学"));
        schoolList.add(new School("尚大大学"));
        student.setSchoolList(schoolList);

        Map teacherMap = new HashMap<>();
        teacherMap.put("t1", new Teacher("xiaoqiu"));
        teacherMap.put("t2", new Teacher("oldqiu"));
        student.setTeacherMap(teacherMap);

        request.setAttribute("student", student);
        processTemplate("demo07", request, response);


    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

    
    



姓名:
    

学科名称:
    

第一个学校名称 :
    

老师姓名:
    

概述

使用th:if、th:unless指令来进行条件渲染。

代码实现

@WebServlet("/demo08")
public class Demo08Servlet extends ViewbaseServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        boolean flag = false;
        request.setAttribute("flag", flag);
        processTemplate("demo08", request, response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

    
    





    这是一个span if



    这是一个span  unless