Java的Struts框架中append标签与generator标签的使用_MySQL
| append 标签： 这些append标签需要两个或两个以上的列表作为参数，并追加它们放在一起，如下图所示： <s:append var="myAppendIterator"> <s:param value="%{myList1}" /> <s:param value="%{myList2}" /> <s:param value="%{myList3}" /></s:append><s:iterator value="%{#myAppendIterator}"> <s:property /></s:iterator>如果有两个列表A和B的值A1，A2和B1，B2。合并列表，会给你的A1，A2，B1，B2，而append 名单，会有A1，A2，B1，B2。 创建动作类： package com.yiibai.struts2;import java.util.ArrayList;import java.util.List;import org.apache.struts2.util.SubsetIteratorFilter.Decider;public class Employee { private String name; private String department; public Employee(){} public Employee(String name,String department) { this.name = name; this.department = department; } private List employees; private List contractors; public String execute() { employees = new ArrayList(); employees.add(new Employee("George","Recruitment")); employees.add(new Employee("Danielle","Accounts")); employees.add(new Employee("Melissa","Recruitment")); employees.add(new Employee("Rose","Accounts")); contractors = new ArrayList(); contractors.add(new Employee("Mindy","Database")); contractors.add(new Employee("Vanessa","Network")); return "success"; } public Decider getRecruitmentDecider() { return new Decider() { public boolean decide(Object element) throws Exception { Employee employee = (Employee)element; return employee.getDepartment().equals("Recruitment"); } }; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getDepartment() { return department; } public void setDepartment(String department) { this.department = department; } public List getEmployees() { return employees; } public void setEmployees(List employees) { this.employees = employees; } public List getContractors() { return contractors; } public void setContractors(List contractors) { this.contractors = contractors; } }Employee类有两个属性 - name 和 department，我们也有两个员工名单 - employees 和contractors。我们有一个方法叫做getRecruitmentDecider，返回Decider 对象。Decider 实现返回true，如果雇员招聘部门工作，否则返回false。 接下来，让我们创建一个DepartmentComparator比较Employee对象： package com.yiibai.struts2;import java.util.Comparator;public class DepartmentComparator implements Comparator { public int compare(Employee e1, Employee e2) { return e1.getDepartment().compareTo(e2.getDepartment()); } @Override public int compare(Object arg0, Object arg1) { return 0; }}在上面的例子所示，部门比较的基础上按字母顺序排列的部门员工进行比较。 创建视图 <%@ page contentType="text/html; charset=UTF-8"%><%@ taglib prefix="s" uri="/struts-tags"%><html><head><title>Employees</title></head><body> <b>Employees and Contractors Merged together</b> <br /> <s:append id="allemployees"> <s:param value="employees" /> <s:param value="contractors" /> </s:append > <s:iterator value="allemployees"> <s:property value="name"/>, <s:property value="department"/><br/> </s:iterator></body></html> append标签需要两个或两个以上列出作为参数。我们需要给予追加一个id，这样我们就可以重用它。在这个例子中，我们提供了作为参数传递给员工和承包商的附加标签。然后，我们使用“allemployees”ID遍历附加列表和打印员工的细节。 配置文件 <?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="employee" class="com.yiibai.struts2.Employee" method="execute"> <result name="success">/employee.jsp</result> </action> </package></struts> web.xml中，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：
generator 标签: <s:generator val="%{'aaa,bbb,ccc,ddd,eee'}"> <s:iterator> <s:property /><br/> </s:iterator></s:generator>我们经常遇到的一些情况，必须创建列表或数组上遍历列表。可以创建列表或数组使用scriptlet或者可以使用generator 标签。 tag. 创建action类： package com.yiibai.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; }}创建视图 <%@ 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>在这里，我们创建一个generator 标签，我们要求它解析的字符串，其中包含逗号分隔的列表，形成了彩虹的颜色。我们告诉发电机标签，分隔符是“，”我们希望所有七个值在列表中。如果我们只关心前三个值，然后我们会设置计数至3。发电机标记在体内，我们使用了迭代器去通过由generator 标记创建的值的打印属性的值。 配置文件 <?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.yiibai.struts2.HelloWorldAction" method="execute"> <result name="success">/HelloWorld.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/hello.action。这会给出以下画面：
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