学步园

struts2 是支持 velocity 的,所以不需要什么大规模更改.大多就是测试的时候按提示添加缺少的 class.这里让它支持 velocity 的布局功能

首先在项目中新建个类,路径如下.这个类改写了 struts2 里的 velocity 类

package struts2.velocity;<br /> import java.io.OutputStreamWriter;<br /> import java.io.StringWriter;<br /> import java.io.Writer;<br /> import javax.servlet.Servlet;<br /> import javax.servlet.ServletContext;<br /> import javax.servlet.http.HttpServletRequest;<br /> import javax.servlet.http.HttpServletResponse;<br /> import javax.servlet.jsp.JspFactory;<br /> import javax.servlet.jsp.PageContext;<br /> import org.apache.struts2.ServletActionContext;<br /> import org.apache.struts2.dispatcher.VelocityResult;<br /> import org.apache.struts2.views.JspSupportServlet;<br /> import org.apache.struts2.views.velocity.VelocityManager;<br /> import org.apache.velocity.Template;<br /> import org.apache.velocity.context.Context;<br /> import com.opensymphony.xwork2.ActionContext;<br /> import com.opensymphony.xwork2.ActionInvocation;<br /> import com.opensymphony.xwork2.util.ValueStack;<br /> import com.opensymphony.xwork2.util.logging.Logger;<br /> import com.opensymphony.xwork2.util.logging.LoggerFactory;<br /> public class VelocityLayoutResult extends VelocityResult {<br /> private static final long serialVersionUID = 6020934292083047099L;<br /> private static final Logger LOG = LoggerFactory<br /> .getLogger(VelocityLayoutResult.class);<br /> public static String KEY_SCREEN_CONTENT = "screen_content";<br /> public static String KEY_LAYOUT = "layout";<br /> public static final String PROPERTY_DEFAULT_LAYOUT = "tools.view.servlet.layout.default.template";<br /> public static final String PROPERTY_LAYOUT_DIR = "tools.view.servlet.layout.directory";<br /> public static final String PROPERTY_INPUT_ENCODING = "input.encoding";<br /> public static final String PROPERTY_OUTPUT_ENCODING = "output.encoding";<br /> public static final String PROPERTY_CONTENT_TYPE = "default.contentType";<br /> protected VelocityManager velocityManager;<br /> protected String defaultLayout;<br /> protected String layoutDir;<br /> protected String inputEncoding;<br /> protected String outputEncoding;<br /> protected String contentType;<br /> @Override<br /> public void setVelocityManager(VelocityManager mgr) {<br /> this.velocityManager = mgr;<br /> super.setVelocityManager(mgr);<br /> }<br /> @Override<br /> public void doExecute(String finalLocation, ActionInvocation invocation)<br /> throws Exception {<br /> ValueStack stack = ActionContext.getContext().getValueStack();<br /> HttpServletRequest request = ServletActionContext.getRequest();<br /> HttpServletResponse response = ServletActionContext.getResponse();<br /> JspFactory jspFactory = null;<br /> ServletContext servletContext = ServletActionContext<br /> .getServletContext();<br /> Servlet servlet = JspSupportServlet.jspSupportServlet;<br /> velocityManager.init(servletContext);<br /> boolean usedJspFactory = false;<br /> PageContext pageContext = (PageContext) ActionContext.getContext().get(<br /> ServletActionContext.PAGE_CONTEXT);<br /> if (pageContext == null && servlet != null) {<br /> jspFactory = JspFactory.getDefaultFactory();<br /> pageContext = jspFactory.getPageContext(servlet, request, response,<br /> null, true, 8192, true);<br /> ActionContext.getContext().put(ServletActionContext.PAGE_CONTEXT,<br /> pageContext);<br /> usedJspFactory = true;<br /> }<br /> try {<br /> String encoding = getEncoding(finalLocation);<br /> String contentType = getContentType(finalLocation);<br /> if (encoding != null) {<br /> contentType = contentType + ";charset=" + encoding;<br /> }<br /> Template t = getTemplate(stack,<br /> velocityManager.getVelocityEngine(), invocation,<br /> finalLocation, encoding);<br /> Context context = createContext(velocityManager, stack, request,<br /> response, finalLocation);<br /> StringWriter stringWriter = new StringWriter();<br /> t.merge(context, stringWriter);<br /> context.put(KEY_SCREEN_CONTENT, stringWriter.toString());<br /> Object obj = context.get(KEY_LAYOUT);<br /> String layout = (obj == null) ? null : obj.toString();</p> <p> defaultLayout = (String) velocityManager.getVelocityEngine()<br /> .getProperty(PROPERTY_DEFAULT_LAYOUT);</p> <p> layoutDir = (String) request.getAttribute("layoutDir");<br /> //System.out.print(layoutDir);<br /> if(layoutDir ==""){<br /> layoutDir = (String) velocityManager.getVelocityEngine()<br /> .getProperty(PROPERTY_LAYOUT_DIR);<br /> }</p> <p> if (!layoutDir.endsWith("/")) {<br /> layoutDir += '/';<br /> }<br /> if (!layoutDir.startsWith("/")) {<br /> layoutDir = "/" + layoutDir;<br /> }</p> <p> defaultLayout = layoutDir + defaultLayout;</p> <p> if (layout == null) {<br /> layout = defaultLayout;<br /> } else {<br /> if(layout.startsWith("@/")){<br /> layout = layout.replace("@/", "/");<br /> }else{<br /> layout = layoutDir + layout;<br /> }<br /> }<br /> Template layoutVm = null;<br /> try {<br /> inputEncoding = (String) velocityManager.getVelocityEngine()<br /> .getProperty(PROPERTY_INPUT_ENCODING);<br /> layoutVm = getTemplate(stack,<br /> velocityManager.getVelocityEngine(), invocation,<br /> layout, inputEncoding);<br /> } catch (Exception e) {<br /> LOG.error("VelocityLayoutResult: Can't load layout /"" + layout<br /> + "/": " + e);<br /> if (!layout.equals(defaultLayout)) {<br /> layoutVm = getTemplate(stack,<br /> velocityManager.getVelocityEngine(), invocation,<br /> defaultLayout, inputEncoding);<br /> }<br /> }<br /> outputEncoding = (String) velocityManager.getVelocityEngine()<br /> .getProperty(PROPERTY_OUTPUT_ENCODING);<br /> Writer writer = new OutputStreamWriter(response.getOutputStream(),<br /> outputEncoding);<br /> response.setContentType(contentType);<br /> layoutVm.merge(context, writer);<br /> writer.flush();<br /> } catch (Exception e) {<br /> LOG.error("Unable to render Velocity Template, '" + finalLocation<br /> + "'", e);<br /> throw e;<br /> } finally {<br /> if (usedJspFactory) {<br /> jspFactory.releasePageContext(pageContext);<br /> }<br /> }<br /> return;<br /> }<br /> }

WEB-INF下新建个文件.命名:velocity.properties,内容如下(当然可以自己再加别的),用来存放velocity相关的一些信息:

tools.view.servlet.layout.directory =/template/
tools.view.servlet.layout.default.template=defalut.vm
input.encoding=UTF-8
output.encoding=UTF-8

tools.view.servlet.layout.directory =/template/  这行假定所有的 .vm 模板文件都在根目录的
/template 文件夹下,下面的login.vm和blank.vm 都是在这个目录下.

接着配置 struts.xml,在 struts 根节点下加入:

<constant name="struts.velocity.configfile" value="/WEB-INF/velocity.properties"/>

还是 struts.xml 下面这个配置用来输出,注意黑体 :

<package name="default" namespace="/" extends="struts-default">
        <result-types>
            <result-type name="velocity" class="struts2.velocity.VelocityLayoutResult" />
        </result-types>
        <action name="login" class="com.exdoit.Main" method="login">
            <result type="velocity ">/template/login.vm </result>
        </action>
 </package>

这个是 login.vm 的代码 #set($layout = "blank.vm") 用来设置布局模板 .

#set($layout = "blank.vm")
<ul>
    <li><span>帐号:</span><input type="text" name="name" id="loginForm_name" /><span><a href="" target="_blank">用户注册</a></span></li>
    <li><span>密码:</span><input type="password" name="pw" id="loginForm_pw" /><span><a href="" target="_blank">忘记密码</a></span></li>
    <li><input type="button" value="登录" id="loginForm_logonbtn" /><input type="button" value="取消" id="loginForm_cancelbtn" /></li>
</ul>

这个是 blank.vm 的代码 ${screen_content} 就是要替换成 login.vm 的内容

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>${page_title}</title>
<link media="screen,print" rel="stylesheet" href="/common/css/inc.css" type="text/css" charset="utf-8" />
<script type="text/javascript" src="/common/JS/jquery/jquery.js" charset="UTF-8"></script>
<script type="text/javascript" src="/common/JS/common.js"></script>
</head>
<body>
${screen_content}
</body>
</html>

运行测试...

注,struts2.velocity.VelocityLayoutResult 这个类是Google来的.当时忘了记源地址.对原作者表示感谢...

我修改的原版的其中几行.用来设置模板路径这些问题.毕竟有可能不是所有的 vm 文件都一定在 velocity.properties 指定的目录下.

当路径 @/ 开头时,如:#set($layout = "@/other/layout/blank.vm") 表示这路径是从根目录开始.无视 velocity.properties 的路径配置.

在当前项目配置中假如:

#set($layout = "@/other/layout/blank.vm")  == /other/layout/blank.vm

#set($layout = "other/layout/blank.vm")  == /template /other/layout/blank.vm

在action 中设置 request.setAttribute("layoutDir", "/abc/") ,可以指定result 里vm的路径.无视 velocity.properties 的路径配置,注意这个是仅这个 action 的输出结果会换路径,其它action不受影响 .

在当前项目配置中假如:

#set($layout = "@/other/layout/blank.vm")  == /other/layout/blank.vm

#set($layout = "other/layout/blank.vm")  == /abc /other/layout/blank.vm