springmvc集成velocity

偏执的太偏执、 2022-05-11 02:04 235阅读 0赞

velocity是一个基于java的模板引擎，通过特定的语法，可以获取到在java中定义的对象，从而实现页面与java代码的分离。由于JSP需要先转换为Servlet，然后编译为class执行，导致效率较低。在访问量较大时表现较差，velocity则可以作为JSP的替代。

velocity的介绍、语法等可以参考：[https://www.jianshu.com/p/5913903324ff][https_www.jianshu.com_p_5913903324ff]。

这里是一个springmvc集成velocity的显示用户列表和修改用户信息的例子，备忘。

## maven依赖 ##

添加velocity的相关依赖。（注：spring相关的依赖未给出）

<dependency>
      <groupId>org.apache.velocity</groupId>
      <artifactId>velocity</artifactId>
      <version>1.7</version>
    </dependency>
    <dependency>
      <groupId>org.apache.velocity</groupId>
      <artifactId>velocity-tools</artifactId>
      <version>2.0</version>
    </dependency>

> 注意：必须引入spring-context-support依赖，否则velocityConfig配置中configLocation和resourceLoaderPath属性找不到。

## springmvc配置 ##

<context:component-scan base-package="com.tommy.velocity.controller"/>
    
    <mvc:annotation-driven />
    
    <bean id="velocityConfig" class="org.springframework.web.servlet.view.velocity.VelocityConfigurer">
        
        <property name="configLocation" value="classpath:velocity.properties"/>
        
        <property name="resourceLoaderPath" value="/WEB-INF/view/"/>
    </bean>
    
    <bean id="velocityViewResolver" class="org.springframework.web.servlet.view.velocity.VelocityLayoutViewResolver">
        <property name="order" value="0"/>
        <property name="contentType" value="text/html;charset=UTF-8"/>
        <property name="cache" value="true"/>
        <property name="suffix" value=".vm"/>
        <property name="layoutUrl" value="layout/layout.vm"/>
        <property name="exposeSpringMacroHelpers" value="true"/>
        
        <property name="exposeSessionAttributes" value="true"/>
        
        <property name="requestContextAttribute" value="request"/>
        
        <property name="dateToolAttribute" value="dateTool"/>
        <property name="numberToolAttribute" value="numberTool"/>
    </bean>

velocity.properties：

#设置字符集
    #encoding
    input.encoding=UTF-8
    output.encoding=UTF-8
    contentType=text/html;charset=UTF-8
    
    #autoreload when vm changed
    file.resource.loader.cache=false
    file.resource.loader.modificationCheckInterval  =1
    velocimacro.library.autoreload=false

## web.xml配置 ##

<context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    
    <listener>
        <listener-class>org.springframework.web.util.IntrospectorCleanupListener</listener-class>
    </listener>
    
    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>
            org.springframework.web.filter.CharacterEncodingFilter
        </filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    
    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    
    <servlet>
        <servlet-name>rest</servlet-name>
        <description>spring mvc servlet</description>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>
                /WEB-INF/spring-mvc.xml
            </param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>rest</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>

注意配置Spring的字符集过滤器，否则向后台提交数据时中文乱码。

## 模板文件 ##

布局模板：

<html> <head> <title>$!page_title</title> #parse("default/header.vm") </head> <body> <div> $screen_content </div> </body> </html>

header.vm:

展示用户列表的模板：

<html> <head> <title>Spring MVC and Velocity</title> </head> <body> <h1>Spring MVC and Velocity</h1> <table> <tr> <td>id</td> <td>姓名</td> <td>age</td> <td>操作</td> </tr> #foreach($user in $users) <tr> <td>$!{user.id}</td> <td>$!{user.name}</td> <td>$!{user.age}</td> <td><a href="/preEdit?userId=${user.id}">修改</a></td> </tr> #end </table> </body> </html>

修改的模板：

<html> <head> <title>Spring MVC and Velocity</title> </head> <body> <h1>Spring MVC and Velocity</h1> <form action="/edit" method="post"> <input type="hidden" name="id" value="${user.id}" /> 姓名：<input type="text" name="name" value="$!{user.name}" /><br> 年龄：<input type="text" name="age" value="$!{user.age}" /> <input type="submit" value="提交" /> </form> </body> </html>

## controller ##

@Controller public class HelloController { private final static Map<Integer,User> users = new HashMap<>(8); static { initData(); } @RequestMapping(value = "/list") public String showList(ModelMap map) { map.put("users",users); return "/list"; } @RequestMapping(value = "/preEdit") public String preEdit(ModelMap map, Integer userId) { User user = users.get(userId); map.put("user",user); return "/edit"; } @RequestMapping(value = "/edit") public String edit(ModelMap map, User user) { users.put(user.getId(),user); return showList(map); } private static void initData() { for (int i=0;i<8;i++) { User user = new User(); user.setId(i); user.setName("测试用户" + i); user.setAge((int) (Math.random()*100+10)); users.put(i, user); } } }

User:

public class User { private int id; private String name; private int age; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } }

演示：  
列表页面  
![22517675.jpg][]  
修改一个用户名称  
![57154262.jpg][]  
再次回到列表页面  
![42027621.jpg][]

本文示例代码：[https://gitee.com/tommy88/my-test-projects][https_gitee.com_tommy88_my-test-projects]下的spring-velocity模块。

本文参考：[springmvc集成 velocity,实现多视图整合(jsp,velocity)][springmvc_ velocity_jsp_velocity]

[https_www.jianshu.com_p_5913903324ff]: https://www.jianshu.com/p/5913903324ff
[22517675.jpg]: http://omh46px9n.bkt.clouddn.com/18-4-28/22517675.jpg
[57154262.jpg]: http://omh46px9n.bkt.clouddn.com/18-4-28/57154262.jpg
[42027621.jpg]: http://omh46px9n.bkt.clouddn.com/18-4-28/42027621.jpg
[https_gitee.com_tommy88_my-test-projects]: https://gitee.com/tommy88/my-test-projects
[springmvc_ velocity_jsp_velocity]: https://blog.csdn.net/yyychyzzzz/article/details/56679732