struts2 的 標籤的使用

關於struts2的各種標籤的使用，網上資料還是很多的，但是唯獨這個number標籤，資料很少。不知道是不是因爲太簡單，沒人樂意寫。我覺得這個東西還是很有用的，寫幾句。

標籤定義文件：struts-tags.tld在struts2-core-x.x.x.jar 這個包下面，摘抄以下定義出來：

<tag>
    <description><![CDATA[Render a formatted number.]]></description>
    <name>number</name>
    <tag-class>org.apache.struts2.views.jsp.NumberTag</tag-class>
    <body-content>empty</body-content>
    <attribute>
      <description><![CDATA[The currency to use for a currency format]]></description>
      <name>currency</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
      <description><![CDATA[Whether grouping is used]]></description>
      <name>groupingUsed</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
      <description><![CDATA[Deprecated. Use 'var' instead]]></description>
      <name>id</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
      <description><![CDATA[Maximum fraction digits]]></description>
      <name>maximumFractionDigits</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
      <description><![CDATA[Maximum integer digits]]></description>
      <name>maximumIntegerDigits</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
      <description><![CDATA[Minimum fraction digits]]></description>
      <name>minimumFractionDigits</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
      <description><![CDATA[Maximum integer digits]]></description>
      <name>minimumIntegerDigits</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
      <description><![CDATA[The number value to format]]></description>
      <name>name</name>
      <required>true</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
      <description><![CDATA[Parse integer only]]></description>
      <name>parseIntegerOnly</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
      <description><![CDATA[The rounding mode to use - not implemented yet as this required Java 1.6]]></description>
      <name>roundingMode</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
      <description><![CDATA[Type of number formatter (currency, integer, number or percent, default is number)]]></description>
      <name>type</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
      <description><![CDATA[Name used to reference the value pushed into the Value Stack]]></description>
      <name>var</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>
    <dynamic-attributes>false</dynamic-attributes>
  </tag>

有興趣就挖掘以下org.apache.struts2.views.jsp.NumberTag類的源碼咯。

寫個例子，一看就清楚了：

Action類：

package test.action;

import java.util.ArrayList;
import java.util.List;
import test.model.User;
import com.opensymphony.xwork2.ActionSupport;

public class TestAction extends ActionSupport {
	private static final long serialVersionUID = 2752911709036089235L;
	private int num;
	private List<User> userList;
	public String testNumber(){
		num = 56466126;
		userList = new ArrayList<User>();
		userList.add(new User("Mike",4546645));
		userList.add(new User("Sam",2389469));
		userList.add(new User("Keven",8923741));
		return SUCCESS;
	}
	
	//getter and setter
	public int getNum() {
		return num;
	}
	public void setNum(int num) {
		this.num = num;
	}
	public List<User> getUserList() {
		return userList;
	}
	public void setUserList(List<User> userList) {
		this.userList = userList;
	}
}

User.java

package test.model;

public class User {
	private String name;
	private int salary;
	
	public User(){}
	
	public User(String name,int salary){
		this.name = name;
		this.salary = salary;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getSalary() {
		return salary;
	}
	public void setSalary(int salary) {
		this.salary = salary;
	}
}

JSP: number.jsp

<%@ taglib prefix="s" uri="/struts-tags"%>

<s:property value="num"/><br>

<s:number name="num" groupingUsed="true" type="currency" maximumFractionDigits="0" /><br>
<s:number name="num" groupingUsed="true" type="integer" maximumFractionDigits="0" /><br>
<s:number name="num" groupingUsed="true" type="integer" maximumFractionDigits="2" minimumFractionDigits="2"/>
<br>
<br>
<s:iterator value="userList" >
	<s:property value="name"/> <s:number name="salary" groupingUsed="true" type="integer" maximumFractionDigits="0" /><br>
</s:iterator>

<br>
<br>
<s:iterator value="userList" >
	<s:property value="name"/> <s:number name="salary" groupingUsed="true" type="currency" maximumFractionDigits="2" minimumFractionDigits="2"/><br>
</s:iterator>

struts.xml

<action name="number" class="test.action.TestAction" method="testNumber" >
			<result name="success" >/number.jsp</result>
		</action>

該標籤的其他屬性：

沒啥好說的，就這樣。