FreeMarker-在servlet上使用

采用servlet+maven搭建demo

创建Maven项目，引入依赖包

<project xmlns="http://maven.apache.org/POM/4.0.0"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
       <modelVersion>4.0.0</modelVersion>
       <groupId>com.hu</groupId>
       <artifactId>maven-freemarker-demo</artifactId>
       <version>0.0.1-SNAPSHOT</version>
       <packaging>war</packaging>
       <dependencies>
               <dependency>
                       <groupId>javax.servlet</groupId>
                       <artifactId>jsp-api</artifactId>
                       <version>2.0</version>
                       <scope>provided</scope>
               </dependency>
               <dependency>
                       <groupId>javax.servlet</groupId>
                       <artifactId>javax.servlet-api</artifactId>
                       <version>3.0.1</version>
                       <scope>provided</scope>
               </dependency>
               <dependency>
                       <groupId>org.freemarker</groupId>
                       <artifactId>freemarker</artifactId>
                       <version>2.3.20</version>
               </dependency>
       </dependencies>
       <build>
               <plugins>
                       <plugin>
                               <groupId>org.apache.tomcat.maven</groupId>
                               <artifactId>tomcat7-maven-plugin</artifactId>
                               <version>2.2</version>
                               <configuration>
                                       <!-- 控制 tomcat 端口号 -->
                                       <port>801</port>
                                       <!-- 项目发布到 tomcat 后的名称 -->
                                       <path>/</path>
                               </configuration>
                       </plugin>
               </plugins>
               <!-- 配置编译文件 -->
               <resources>
                       <!-- src/main/java 里面的资源文件进行编译到classes 中 -->
                       <resource>
                               <directory>src/main/java</directory>
                               <includes>
                                       <include>**/*.xml</include>
                               </includes>
                       </resource>
                       <!-- 上面修改了默认配置，打破了规则，也要配置把resources中的资源文件让其被编译到class -->
                       <resource>
                               <directory>src/main/resources</directory>
                               <includes>
                                       <include>**/*.xml</include>
                                       <include>**/*.properties</include>
                               </includes>
                       </resource>
               </resources>
       </build>
</project>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns="http://java.sun.com/xml/ns/javaee"
       xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
       version="3.0">
       <servlet>
               <servlet-name>freemarker</servlet-name>
               <servlet-class>freemarker.ext.servlet.FreemarkerServlet</servlet-class>
               <!--下面的配置freemarke的ftl文件或者html，jsp等页面的位置 -->
               <init-param>
                       <param-name>TemplatePath</param-name>
                       <param-value>/freeMarker</param-value>
               </init-param>
               <!-- 可选配置  -->
       <init-param>
           <param-name>NoCache</param-name>
           <param-value>true</param-value>
       </init-param>
       <init-param>
           <param-name>ContentType</param-name>
           <param-value>text/html; charset=UTF-8</param-value>
       </init-param>
       <init-param>
           <param-name>template_update_delay</param-name>
           <param-value>0</param-value>
       </init-param>
       <init-param>
           <param-name>default_encoding</param-name>
           <param-value>ISO-8859-1</param-value>
       </init-param>
       <init-param>
           <param-name>number_format</param-name>
           <param-value>0.##########</param-value>
       </init-param>
       
       <!-- 是否和服务器（tommcat)一起启动。-->
               <load-on-startup>1</load-on-startup>
       </servlet>

       <servlet-mapping>
               <servlet-name>freemarker</servlet-name>
               <url-pattern>*.ftl</url-pattern><!--页面的后缀，如果页面是ftl文件就写*.ftl,如果是html就写*.html -->
       </servlet-mapping>
</web-app>

在创建模板文件：webapp/freeMarker/demo.ftl

<html>
<head>
   <title>FreeMarker Hello World</title>
</head>
<body>
<table class="datatable">
   <#list users as user>
       <tr>
           <td>${user.id}</td> <td>${user.name}</td>
       </tr>
   </#list>
</table>
</body>
</html>

Servlet：

@WebServlet("/free")
public class FreeMarkerServlet extends HttpServlet {
       private static final long serialVersionUID = 1L;
       
       @Override
       protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
               System.out.println(1111111111);
               List<Map<String, Object>> users = new ArrayList<>();
               for (int i = 0; i < 3; i++) {
                       Map<String, Object> user = new HashMap<>();
                       user.put("id",  i);
                       user.put("name", "Hello FreeMarker");
                       users.add(user);
               }
               request.setAttribute("users", users);
               request.getRequestDispatcher("demo.ftl").forward(request, response);
       }

}