Java的Struts框架中append標簽與generator標簽的應用。本站提示廣大學習愛好者:(Java的Struts框架中append標簽與generator標簽的應用)文章只能為提供參考,不一定能成為您想要的結果。以下是Java的Struts框架中append標簽與generator標簽的應用正文
append 標簽:
這些append標簽須要兩個或兩個以上的列表作為參數,並追加它們放在一路,以下圖所示:
<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>
假如有兩個列表A和B的值A1,A2和B1,B2。歸並列表,會給你的A1,A2,B1,B2,而append 名單,會有A1,A2,B1,B2。
創立舉措類:
起首,讓我們創立一個簡略的類叫做Employee.java,它看起來像:
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類有兩個屬性 - name 和 department,我們也有兩個員工名單 - employees 和contractors。我們有一個辦法叫做getRecruitmentDecider,前往Decider 對象。Decider 完成前往true,假如雇員雇用部分任務,不然前往false。
接上去,讓我們創立一個DepartmentComparator比擬Employee對象:
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; } }
在下面的例子所示,部分比擬的基本上按字母次序分列的部分員工停止比擬。
創立視圖
創立一個文件叫做employee.jsp以下內容:
<%@ 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標簽須要兩個或兩個以上列出作為參數。我們須要賜與追加一個id,如許我們便可以重用它。在這個例子中,我們供給了作為參數傳遞給員工和承包商的附加標簽。然後,我們應用“allemployees”ID遍歷附加列表和打印員工的細節。
設置裝備擺設文件
struts.xml中應當像如許:
<?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,應當像如許:
<?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>
右鍵點擊項目稱號,並單擊Export > WAR File 創立一個WAR文件。然後安排此WAR在Tomcat的webapps目次下。最初,啟動Tomcat辦事器和測驗考試拜訪URL http://localhost:8080/HelloWorldStruts2/employee.action。這會給出以下畫面:
generator 標簽:
generator標簽生成一個迭代器的基本上供給val屬性。以下generator標簽生成一個迭代器,並應用迭代器標簽打印出來。
<s:generator val="%{'aaa,bbb,ccc,ddd,eee'}"> <s:iterator> <s:property /><br/> </s:iterator> </s:generator>
我們常常碰到的一些情形,必需創立列表或數組上遍歷列表。可以創立列表或數組應用scriptlet或許可使用generator 標簽。 tag.
創立action類:
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; } }
創立視圖
以下 helloWorld.jsp 展現應用generator 標志:
<%@ 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>
在這裡,我們創立一個generator 標簽,我們請求它解析的字符串,個中包括逗號分隔的列表,構成了彩虹的色彩。我們告知發機電標簽,分隔符是“,”我們願望一切七個值在列表中。假如我們只關懷前三個值,然後我們會設置計數至3。發機電標志在體內,我們應用了迭代器去經由過程由generator 標志創立的值的打印屬性的值。
設置裝備擺設文件
struts.xml 應當像如許:
<?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 應當像如許:
<?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>
右鍵點擊項目稱號,並單擊Export > WAR File 創立一個WAR文件。然後安排此WAR在Tomcat的webapps目次下。最初,啟動Tomcat辦事器和測驗考試拜訪URL http://localhost:8080/HelloWorldStruts2/hello.action。這會給出以下畫面: