Spring遇见问题（三）-----FreeMarker自定义标签

web.xml文件

<?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"  id="WebApp_ID" version="3.0">  <display-name>Springmvc3.2.5</display-name><servlet>  <servlet-name>springmvc</servlet-name>  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>  <init-param>        <param-name>contextConfigLocation</param-name>        <param-value>classpath:springmvc-config.xml</param-value>      </init-param>  <load-on-startup>1</load-on-startup></servlet><servlet-mapping>  <servlet-name>springmvc</servlet-name>  <url-pattern>/</url-pattern></servlet-mapping></web-app>

springmvc-config.xml

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:p="http://www.springframework.org/schema/p"xmlns:context="http://www.springframework.org/schema/context"xmlns:mvc="http://www.springframework.org/schema/mvc"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc.xsd"default-lazy-init="true"><!-- 注解方式 --><!-- 自动扫描controller包下的所有类，使其认为spring mvc的控制器 --><context:component-scan base-package="com.springmvc.controller"/><context:component-scan base-package="com.springmvc.directive" /><!-- HandlerMapping --><bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"/><!-- HandlerAdapter --><bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"/><!-- ViewResolver --><bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"><property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/><property name="prefix" value="/WEB-INF/jsp/"/><property name="suffix" value=".jsp"/></bean><bean class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver"><property name="prefix" value="" /><property name="suffix" value=".ftl"/><property name="contentType" value="text/html;charset=UTF-8"></property>          <property name="order" value="0"></property></bean><bean id="freemarkerConfig"        class="org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer">  <!-- 其中一下代码是用来扫描.ftl的模板文件，在/WEB-INF/ftl目录中 -->    <property name="templateLoaderPath" value="/WEB-INF/ftl/" /><property name="freemarkerSettings">          <props><prop key="template_update_delay">0</prop>  <prop key="default_encoding">UTF-8</prop>  <prop key="number_format">0.##########</prop>  <prop key="datetime_format">yyyy-MM-dd HH:mm:ss</prop>  <prop key="classic_compatible">true</prop>  <prop key="template_exception_handler">ignore</prop>  </props>  </property><!-- 自定义标签的关联配置 --><property name="freemarkerVariables"> <map> <entry key="K2" value-ref="F4" /><entry key="ShowLsit" value-ref="show_list" /></map></property> </bean> </beans>

在com.springmvc.directive包下定义一个标签类继承TemplateDirectiveModel

package com.springmvc.directive;import java.io.IOException;import java.util.Map;import static freemarker.template.ObjectWrapper.DEFAULT_WRAPPER;import org.springframework.stereotype.Service;import freemarker.core.Environment;import freemarker.template.SimpleScalar;import freemarker.template.TemplateDirectiveBody;import freemarker.template.TemplateDirectiveModel;import freemarker.template.TemplateException;import freemarker.template.TemplateModel;@Service("F4")public class TestDirective implements TemplateDirectiveModel {/** *  * Environment env 当前HTML/FTL的环境引用 * Map params 自定义标签的属性参数 * TemplateModel[] loopVars待处理（暂定为无用） * TemplateDirectiveBody body 标签体内部内容引用 */@Overridepublic void execute(Environment env, Map params, TemplateModel[] loopVars,                TemplateDirectiveBody body) throws TemplateException, IOException {String text = "";int length = 0;//获取F4标签上的text属性上的值if (params.get("text") != null) {text = ((SimpleScalar) params.get("text")).getAsString();}if (params.get("length") != null) {length = Integer.valueOf(((SimpleScalar) params.get("length")).getAsString());}if (length < text.length()) {text = "..." + text.substring(text.length() - length);}env.setVariable("key", DEFAULT_WRAPPER.wrap(text));        if (body != null) {            body.render(env.getOut());        }else {        env.getOut().write(text);        }}}

com.springmvc.controller包下定义Controller类

package com.springmvc.controller;import java.util.ArrayList;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.servlet.ModelAndView;import com.springmvc.bean.UserBean;@Controller //①将一个POJO类声明为处理器//@RequestMapping(value="/user") //做窄化处理public class HelloWorldController {@RequestMapping(value="/hello")public ModelAndView helloWorld2() {ModelAndView mv = new ModelAndView();mv.addObject("message", "AAAAAAA");mv.setViewName("hello");return mv;}//@RequestMapping(value={"/hello2","/haha","/xixi"})//②请求URL到处理器功能处理方法的映射//public ModelAndView helloWorld(HttpServletRequest request, HttpServletResponse response, HttpSession session) {////1、收集参数//2、绑定参数到命令对象////3、调用业务对象//4、选择下一个页面//ModelAndView mv = new ModelAndView();////添加模型数据可以是任意的POJO对象//mv.addObject("message", "Hello World!");////设置逻辑视图名，视图解析器会根据该名字解析到具体的视图页面//mv.setViewName("hello");//return mv; //3 模型数据和逻辑视图名//}@RequestMapping("/dome")public ModelAndView freemarkerDome(HttpServletRequest request, HttpServletResponse response, HttpSession session) {ModelAndView mv = new ModelAndView();ArrayList<UserBean> list = new ArrayList<>();UserBean userBean = new UserBean();userBean.setUser_id("AAA");userBean.setUser_name("学生");userBean.setUser_age(21);list.add(userBean);userBean = new UserBean();userBean.setUser_id("BBB");userBean.setUser_name("小朋友");userBean.setUser_age(12);list.add(userBean);userBean = new UserBean();userBean.setUser_id("CCC");userBean.setUser_name("老师");userBean.setUser_age(50);list.add(userBean);mv.addObject("list", list);mv.setViewName("tt");return mv;}}

指向tt.ftl文件

<!DOCTYPE html><html><head><meta charset="UTF-8"><title>ftl</title></head><body><div style="border:#F33 2px solid;width:20%;float:left;margin-left:50px;padding: 5px;"><h2>后台传值 list形式取出<br/></h2><#list list as user>userID : ${user.user_id}<br/>userName : ${user.user_name}<br/>userAge : #{user.user_age}<br/></#list></div><div style="border:#F33 2px solid;width:20%;float:left;margin-left:50px;padding: 5px;"><#assign x = "自定义标签测试" /><h2>${x}<br/></h2><#assign x = 23.45637 />#{x}<br><@K2 text="1234567" length="6"><input type="text" value=${key}></@K2><br/><@K2 text="TTTTTTTTTTTTT" length="6"><input type="text" value=${key}></@K2><br/><@K2 text="=============" length="6"></@K2></div><div style="border:#F33 2px solid;width:20%;float:left;margin-left:50px;padding: 5px;"><#import "/macrotest.ftl" as BB><@BB.page title="宏练习"><ul style="color:#F0F;"><li>spring</li><li>j2ee</li></ul></@BB.page></div><div style="border:#F33 2px solid;width:20%;float:left;margin-left:50px;padding: 5px;"><@ShowLsit text="user" value=user stylex="4"></@ShowLsit></div></body></html>

这样一个整体的配置使用流程就形成了。