action标记允许程序员从视图页面执行动作。他们可以做到这一点通过指定的动作名称。他们可以设置的“executeresult”参数设置为“true”,在视图中直接呈现结果。或者他们可以将此参数设置为“false”,但利用请求属性暴露的操作方法。
package com.h3.struts2; public class helloworldaction{ private string name; public string execute() throws exception { return "success"; } public string getname() { return name; } public void setname(string name) { this.name = name; } }
让我们具有 helloworld.jsp 展示使用generator 标记:
<%@ page contenttype="text/html; charset=utf-8" %> <%@ taglib prefix="s" uri="/struts-tags" %> <html> <head> <title>hello world</title> </head> <body> <h2>example of generator tag</h2> <h3>the colours of rainbow:</h3> <s:generator val="%{'violet,indigo,blue, green,yellow,orange,red '}" count="7" separator=","> <s:iterator> <s:property /><br/> </s:iterator> </s:generator> </body> </html>
接下来让我们有employees.jsp包含以下内容:
<%@ page contenttype="text/html; charset=utf-8"%> <%@ taglib prefix="s" uri="/struts-tags"%> <html> <head> <title>employees</title> </head> <body> <s:action name="hello" executeresult="true"> output from hello: <br /> </s:action> </body> </html>
struts.xml 应该像这样:
<?xml version="1.0" encoding="utf-8"?> <!doctype struts public "-//apache software foundation//dtd struts configuration 2.0//en" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <constant name="struts.devmode" value="true" /> <package name="helloworld" extends="struts-default"> <action name="hello" class="com.h3.struts2.helloworldaction" method="execute"> <result name="success">/helloworld.jsp</result> </action> <action name="employee" class="com.h3.struts2.employee" method="execute"> <result name="success">/employee.jsp</result> </action> </package> </struts>
web.xml 应该像这样:
<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 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>struts 2</display-name> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <filter> <filter-name>struts2</filter-name> <filter-class> org.apache.struts2.dispatcher.filterdispatcher </filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>
右键点击项目名称,并单击 export > war file 创建一个war文件。然后部署此war在tomcat的webapps目录下。最后,启动tomcat服务器和尝试访问url http://localhost:8080/helloworldstruts2/employee.action。这会给出以下画面:
正如可以看到在这个例子中,我们指定为“true”的值executeresult。因此,hello.action结果是直接在网页上呈现。helloworld.jsp打印彩虹的颜色 - 这是现在employee.jsp呈现
现在,让我们稍微修改 helloworldaction.java:
package com.h3.struts2; import java.util.arraylist; import java.util.list; import org.apache.struts2.servletactioncontext; public class helloworldaction{ private string name; public string execute() { list names = new arraylist(); names.add("robert"); names.add("page"); names.add("kate"); servletactioncontext.getrequest().setattribute("names", names); return "success"; } public string getname() { return name; } public void setname(string name) { this.name = name; } }
最后,修改employee.jsp,如下所示:
<%@ page contenttype="text/html; charset=utf-8"%> <%@ taglib prefix="s" uri="/struts-tags"%> <html> <head> <title>employees</title> </head> <body> <s:action name="hello" executeresult="false"> output from hello: <br /> </s:action> <s:iterator value="#attr.names"> <s:property /><br /> </s:iterator> </body> </html>
再次右键点击项目名称,并单击export > war file创建一个war文件。然后部署此war在tomcat 的 webapps目录下。
最后,启动tomcat服务器和尝试访问url http://localhost:8080/helloworldstruts2/employee.action。这会给出以下画面: