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 程式師世界 >> 數據庫知識 >> MYSQL數據庫 >> MySQL綜合教程 >> Java的Struts框架中append標簽與generator標簽的應用

Java的Struts框架中append標簽與generator標簽的應用

編輯:MySQL綜合教程

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:

2015124172633013.jpg (560×267)

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:

2015124172721265.jpg (560×297)

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