Spring mvc系列8之 页面静态化(二)

前一章讲到页面静态化当中freeMarker标签的使用,这一章我们使用spring mvc结合freeMarker处理大型网站页面静态化.

第一步:引入除spring mvc 所需的jar包(之前系列的文章讲过,大家可以看之前的文章),还需要引入freemarker-xxx.jar commons-logging-xxx.jar  

第二步:扩展FreeMarkerView,使我们可以控制是否生成静态页面以及生成的静态页面存放的位置.

package gd.hz;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.Locale;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.support.RequestContextUtils;
import org.springframework.web.servlet.view.freemarker.FreeMarkerView;

import freemarker.template.SimpleHash;
import freemarker.template.Template;
import freemarker.template.TemplateException;

public class ExFreeMarkerView extends FreeMarkerView {
	 @Override
	    protected void doRender(Map<String, Object> model,
	            HttpServletRequest request, HttpServletResponse response)
	            throws Exception {
		 
	        exposeModelAsRequestAttributes(model, request);
	        
	        SimpleHash fmModel = buildTemplateModel(model, request, response);
	 
	        if (logger.isDebugEnabled()) {
	            logger.debug("Rendering FreeMarker template [" + getUrl() + "] in FreeMarkerView '" + getBeanName() + "'");
	        }
	        
	        Locale locale = RequestContextUtils.getLocale(request);
	         
	        /*
	         * 在这里我们默认生成静态文件,当ModelAndView有指定STATIC_HTML = false时,就不会输出HTML文件
	         * 例如：ModelAndView modelAndView = new ModelAndView("htmlTest");
	         *       modelAndView.addObject("STATICHTML", false); 
	         */
	        if(Boolean.FALSE.equals(model.get("STATIC_HTML"))){
	            processTemplate(getTemplate(locale), fmModel, response);
	        }else{
	            createHTML(getTemplate(locale), fmModel, request, response);
	        }
	    }
	 
	    public void createHTML(Template template, SimpleHash model,HttpServletRequest request,
	            HttpServletResponse response) throws IOException, TemplateException, ServletException {
	            //站点根目录的绝对路径
	            String basePath = request.getSession().getServletContext().getRealPath("/");
	            String requestHTML = this.getRequestHTML(request);
	            
	            //静态页面绝对路径
	            String htmlPath = basePath + requestHTML;
	             
	            File htmlFile = new File(htmlPath);
	            
	            if(!htmlFile.getParentFile().exists()){
	                htmlFile.getParentFile().mkdirs();
	            }
	            
	            /**
	             * 如果静态页面已经存在,就不再创建静态页面.
	             */
	            if(!htmlFile.exists()){
	                htmlFile.createNewFile();
	                Writer out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(htmlFile), "UTF-8"));
		            //处理模版  
		            template.process(model, out);
		            out.flush();
		            out.close();
	            }
	            /*将请求转发到生成的htm文件*/
	            request.getRequestDispatcher(requestHTML).forward(request, response);
	    }
	     
	    /**
	     * 计算要生成的静态文件相对路径.
	     */
	    private String getRequestHTML(HttpServletRequest request){
	        
	    	//web应用名称,部署在ROOT目录时为空
	        String contextPath = request.getContextPath();
	        
	        //web应用/目录/文件.do
	        String requestURI = request.getRequestURI();
	        
	        //basePath里面已经有了web应用名称，所以直接把它replace掉，以免重复
	        requestURI = requestURI.replaceFirst(contextPath, "");
	       
	        //将.do改为.htm,稍后将请求转发到此htm文件
	        requestURI = requestURI.substring(0, requestURI.indexOf(".")) + ".htm";
	         
	        return requestURI;
	    }
}

 这里我们取出STATIC_HTML的值,当为false是就不生成静态页面.

而getRequestHTML()方法是生成静态页面的相对路径,这里我们可以灵活处理,可以决定静态页面的存放路径.

第三步:配置spring mvc配置文件,这里我的文件名为springmvc.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/beans      
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd      
           http://www.springframework.org/schema/context      
           http://www.springframework.org/schema/context/spring-context-3.0.xsd     
           http://www.springframework.org/schema/mvc      
           http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">
	<!-- 开启注解扫描功能 -->
	<context:component-scan base-package="gd.hz.controller"></context:component-scan>

	<!-- 将上面两个注解和并 -->
	<mvc:annotation-driven />

	
    <!--freemarker页面解析器 -->
    <bean id="viewResolver"
        class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
        <property name="suffix" value=".ftl"></property>
        <property name="contentType" value="text/html;charset=UTF-8" />
<!--         <property name="viewClass" value="org.springframework.web.servlet.view.freemarker.FreeMarkerView" /> -->
        <!-- 将Spring的FreeMarkerView改成我们扩展的View -->
        <property name="viewClass" value="gd.hz.ExFreeMarkerView" />
        <property name="exposeRequestAttributes" value="true" />
        <property name="exposeSessionAttributes" value="true" />
        <property name="exposeSpringMacroHelpers" value="true" />
    </bean>
 
    <bean id="fmXmlEscape" class="freemarker.template.utility.XmlEscape" />
 
    <!--配置Freemarker -->
    <bean id="freemarkerConfigurer"
        class="org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer">
        <!-- 模版页面存放的位置 -->
         <property name="templateLoaderPath" value="/ftl/"></property>
        <property name="freemarkerVariables">
            <map>
                <entry key="xml_escape" value-ref="fmXmlEscape" />
            </map>
        </property>
        <property name="freemarkerSettings">
            <props>
                <prop key="template_update_delay">10</prop>
                <prop key="defaultEncoding">UTF-8</prop>
            </props>
        </property>
    </bean>
    
    <!-- 下面要声明在模版后面 -->
    <bean
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<!-- JSP页面存放的位置 -->
		<property name="prefix" value="/jsp/" />
		<property name="suffix" value=".jsp" />
	</bean> 
</beans>

 这里页面额外说明的是,如果我们想一个网站有使用freeMarker和jsp时,也可以在配置文件中声明如:

<bean
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<!-- JSP页面存放的位置 -->
		<property name="prefix" value="/jsp/" />
		<property name="suffix" value=".jsp" />
	</bean> 

 这句话要声明在使用freeMarker配置下面,这样当处sping 找不到相关页面模板时就会找相关名称的jsp页面.另外还需要声明使用我们扩展的ExFreeMarkerView.

第四步:创建测试页:

模板页:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title></title>
</head>
<body>
	${content}
</body>
</html>

JSP页面:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title></title>
</head>
<body>
我是从jsp过来的.${content }
</body>
</html

第五步:Controller

package gd.hz.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller("indexController")
public class IndexController {

    @RequestMapping("index")
    public ModelAndView index(){
        ModelAndView modelAndView = new ModelAndView("index");
        modelAndView.addObject("content", "网站标题");
        
        //当设置false时不生成静态页面
        modelAndView.addObject("STATIC_HTML", false);
        
        return modelAndView;
    }
    
    @RequestMapping("html/index")
    public ModelAndView htmlIndex(){
        ModelAndView modelAndView = new ModelAndView("index");
        //默认是生成静态页面的
        modelAndView.addObject("content", "网站标题");
        return modelAndView;
    }
    
    //jsp测试
    @RequestMapping("jsp/index")
    public ModelAndView jspindex(){
        ModelAndView modelAndView = new ModelAndView("test");
        modelAndView.addObject("content", "网站标题");
        return modelAndView;
    }
}

 首先看一下第一个请求,这里我们声明STATIC_HTML=false,不生成静态页面.第二个请求,我们生成的静态页面,根据ExFreeMarkerView中的定义,会跳转到静态页面.

第三个请求,因为没有test.ftl,这样spring 会去找test.jsp页面,所发请求会到test.jsp.

经过上面的三种方法,我们使用在进行大型网站开发时,可以灵活运用,可以在页面的某些数据变化少的地方进行部分页面静态化.也可以根据需求,只请求JSP页面.