FreeMarker与Servlet结合示例
一、最原始示例
1、引入POM依赖
<!-- https://mvnrepository.com/artifact/org.freemarker/freemarker --> <dependency> <groupId>org.freemarker</groupId> <artifactId>freemarker</artifactId> <version>2.3.26-incubating</version> </dependency> <!-- Servlet Library --> <!-- http://mvnrepository.com/artifact/javax.servlet/javax.servlet-api --> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> <scope>provided</scope> </dependency>
2、在WEB-INF/ftl中建立test.ftl
<html> <head> <title>Welcome!</title> </head> <body> <h1> Welcome ${user}<#if user == "Big Joe">, our beloved leader</#if>! </h1> </body> </html>
3、添加TestServlet.java
package com.jsoft.testfreemarker; import java.io.IOException; import java.util.HashMap; import java.util.Map; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import freemarker.template.Configuration; import freemarker.template.Template; /** * Servlet implementation class TestServlet */ @WebServlet(name = "test", urlPatterns = "/test") public class TestServlet extends HttpServlet { private static final long serialVersionUID = 1L; private Configuration cfg; @Override public void init() throws ServletException { // initialize operation cfg = new Configuration(Configuration.VERSION_2_3_26); cfg.setServletContextForTemplateLoading(getServletContext(), "WEB-INF/ftl"); } /** * Default constructor. */ public TestServlet() { // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse * response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setCharacterEncoding("utf-8"); Map<String, Object> data = new HashMap<String, Object>(); data.put("user", "Big Joe"); // 得到模板 try { // 将模板和数据结合，并返回浏览器 Template template = cfg.getTemplate("test.ftl"); template.process(data, response.getWriter()); } catch (Exception e) { // e.printStackTrace(); response.getWriter().print("暂时无数据"); } } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse * response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
提示：采用了Servlet3.x的注解功能，不需要在web.xml中再配置映射。
4、测试效果
测试工程：https://github.com/easonjim/5_java_example/tree/master/freemarker/test2
二、高级一点的集成
1、在web.xml引入FreeMarker提供的Servlet
<servlet> <servlet-name>freemarker</servlet-name> <servlet-class>freemarker.ext.servlet.FreemarkerServlet</servlet-class> <init-param> <param-name>TemplatePath</param-name> <param-value>/</param-value> </init-param> <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>UTF-8</param-value> </init-param> <init-param> <param-name>number_format</param-name> <param-value>0.##########</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>freemarker</servlet-name> <url-pattern>*.ftl</url-pattern> </servlet-mapping>
2、新建test.ftl模板文件
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh-CN" dir="ltr"> <head> <title>test!</title> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> </head> <body> <div> 直接显示字符串<br /> String:${strValue}<br/> <hr/> </div> <div> 显示日期 date:${myDate?date}<br/> <hr/> 显示时间 time:${myDate?time}<br/> <hr/> 显示时间戳 datetime:${myDate?datetime}<br/> <hr/> </div> <div> 访问对象数组 ObjectArray: ${objectArray[0]},${objectArray[1]},${objectArray[2]} <br /> <hr/> </div> <div> 遍历Set中的元素 SetData:<br /> <#list setData as value> ${value} </#list> <hr/> </div> <div> 遍历List中的元素 strList:<br/> <#list strList as strValue > <#if strValue_index == 0> ${strValue} is first element <#elseif !strValue_has_next> ${strValue} is last element <#else> ${strValue} </#if> <br /> </#list> <hr/> </div> <div> 获取map中的值 <br/> map: key1=${map.key1},key2=${map.key2},key3=${map.key3} <hr/> </div> <#include "foot.html"> </body> </html>
foot.html为了演示模板中引入文件的效果
<div style="margin-top: 50px;text-align: center;font-size: 12px"> <hr /> this is foot </div>
3、编写Servlet，这次的Servlet完全不用涉及到FreeMarker的类库使用，只关心Model即可。
package com.jsoft.testfreemarker; import java.io.IOException; import java.util.ArrayList; import java.util.Date; import java.util.HashMap; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Set; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class TestServlet */ @WebServlet(name = "test", urlPatterns = "/test") public class TestServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * Default constructor. */ public TestServlet() { // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse * response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String strValue = "this is String"; Date myDate = new Date(); Object[] objectArray = new Object[] { 1, "str", 1.2 }; Set<Object> setData = new HashSet<Object>(); setData.add("dataValue1"); setData.add("dataValue2"); setData.add("dataValue3"); List<String> strList = new ArrayList<String>(); strList.add("字符串1"); strList.add("字符串2"); strList.add("字符串3"); Map<String, Object> map = new HashMap<String, Object>(); map.put("key1", "value1"); map.put("key2", "value2"); map.put("key3", "value3"); request.setAttribute("strValue", strValue); request.setAttribute("objectArray", objectArray); request.setAttribute("strList", strList); request.setAttribute("map", map); request.setAttribute("myDate", myDate); request.setAttribute("setData", setData); request.getRequestDispatcher("/WEB-INF/ftl/test.ftl").forward(request, response); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse * response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
4、测试效果
测试工程：https://github.com/easonjim/5_java_example/tree/master/freemarker/test3
