javaweb-thymeleaf，加載jar包---視圖基礎

1.加載完thymeleaf的jar包

將thymeleaf的jar包復制到項目下lib文件夾中

右擊lib文件夾，點擊Add as librarb...

打開Project Structure，找到Modules，點擊加號，點擊Library，找到lib，完成添加

 

2.創建ViewBaseServlet類,並把以下代碼放入類中

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;

public class ViewBaseServlet extends HttpServlet {

    private TemplateEngine templateEngine;

    @Override
    public void init() throws ServletException {

        // 1.獲取ServletContext對象
        ServletContext servletContext = this.getServletContext();

        // 2.創建Thymeleaf解析器對象
        ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(servletContext);

        // 3.給解析器對象設置參數
        // ①HTML是默認模式，明確設置是為了代碼更容易理解
        templateResolver.setTemplateMode(TemplateMode.HTML);

        // ②設置前綴
        String viewPrefix = servletContext.getInitParameter("view-prefix");

        templateResolver.setPrefix(viewPrefix);

        // ③設置后綴
        String viewSuffix = servletContext.getInitParameter("view-suffix");

        templateResolver.setSuffix(viewSuffix);

        // ④設置緩存過期時間（毫秒）
        templateResolver.setCacheTTLMs(60000L);

        // ⑤設置是否緩存
        templateResolver.setCacheable(true);

        // ⑥設置服務器端編碼方式
        templateResolver.setCharacterEncoding("utf-8");

        // 4.創建模板引擎對象
        templateEngine = new TemplateEngine();

        // 5.給模板引擎對象設置模板解析器
        templateEngine.setTemplateResolver(templateResolver);

    }

    protected void processTemplate(String templateName, HttpServletRequest req, HttpServletResponse resp) throws IOException {
        // 1.設置響應體內容類型和字符集
        resp.setContentType("text/html;charset=UTF-8");

        // 2.創建WebContext對象
        WebContext webContext = new WebContext(req, resp, getServletContext());

        // 3.處理模板數據
        templateEngine.process(templateName, webContext, resp.getWriter());
    }
}

 3.在web.xml文件中添加配置

<!--    配置前綴 view-prefix   配置后綴 view-suffix　　前后綴可以隨意改變-->
<!--　　物理視圖=配置前綴+邏輯視圖+配置后綴　　-->
    <context-param>
        <param-name>view-prefix</param-name>
        <param-value>/</param-value>
    </context-param>
    <context-param>
        <param-name>view-suffix</param-name>
        <param-value>.html</param-value>
    </context-param>

 

4.創建html頁面

　　在html中的thymeleaf語法：

　　th:if=""　　//if語句
　　th:unless=""　　//else語句
　　th:ecah=""　　//for語句
　　th:text=""　　//文本語句

<tr th:if="${#lists.isEmpty(session.fruitList)}">
                    <td colspan="4">對不起，庫存為空！！</td>
                    </tr>
                    <!--  if是判斷是否為條件真 unless是判斷是否為條件假 each是疊代，從session.list中依次取出一個對象賦給fruit  -->
                    <tr th:unless="${#lists.isEmpty(session.fruitList)}" th:each="fruit : ${session.fruitList}">
                        <td th:text="${fruit.fname}"></td>

                    </tr>

 

5.創建一個servlet類並繼承ViewBaseServlet類

　　在processTemplate方法會執行：物理視圖=配置前綴+邏輯視圖+配置后綴 的操作

 

 

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        FruitDAO fruitDAO = new FruitDAOImpl();
        List<Fruit> fruitList = fruitDAO.getFruitList();
        //將fruitList保存到session作用域中，
        HttpSession session = req.getSession();
        session.setAttribute("fruitList",fruitList);
//        processTemplate(String templateName, HttpServletRequest req, HttpServletResponse resp)
        super.processTemplate("demo07",req,resp);
    }