Struts2标签实现for循环

冷不防 2022-09-30 06:58 115阅读 0赞

在struts2及webwork中要实现如：

for(int i=0;i<10;i++)\{\}

还是需要一些技巧的，我在做分页条的时候，要输出页码，怪了，用迭代器不行的，看了一下struts2的文档及例子也没发现用计数器的地方，偶然看了一下bea标签，哦，原来如此....

<s:bean name="org.apache.struts2.util.Counter" id="counter">  
   <s:param name="first" value="1" />  
   <s:param name="last" value="10" />  
   <s:iterator>  
     counter:<s:property/>  
   </s:iterator>  
</s:bean>

其中first属性指定循环起始值，last指定循环终止值，其它相关属性可以查看org.apache.struts2.util.Counter类源码。在下面迭代器中输入循环的当前值，即：current

干脆把源码贴出来吧！

\-----------------------------------------------------------------------------------------------------------------------------

/\*  
\* $Id: Counter.java 471756 2006-11-06 15:01:43Z husted $  
\*  
\* Licensed to the Apache Software Foundation (ASF) under one  
\* or more contributor license agreements.   See the NOTICE file  
\* distributed with this work for additional information  
\* regarding copyright ownership.   The ASF licenses this file  
\* to you under the Apache License, Version 2.0 (the  
\* "License"); you may not use this file except in compliance  
\* with the License.   You may obtain a copy of the License at  
\*  
\*  [http://www.apache.org/licenses/LICENSE-2.0][http_www.apache.org_licenses_LICENSE-2.0]  
\*  
\* Unless required by applicable law or agreed to in writing,  
\* software distributed under the License is distributed on an  
\* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY  
\* KIND, either express or implied.   See the License for the  
\* specific language governing permissions and limitations  
\* under the License.  
\*/  
package org.apache.struts2.util;

import java.io.Serializable;

/\*\*  
\* A bean that can be used to keep track of a counter.  
\* <p/>  
\* Since it is an Iterator it can be used by the iterator tag  
\*  
\*/  
public class Counter implements java.util.Iterator, Serializable \{

private static final long serialVersionUID = 2796965884308060179L;

boolean wrap = false;

// Attributes ----------------------------------------------------  
     long first = 1;  
     long current = first;  
     long interval = 1;  
     long last = -1;

public void setAdd(long addition) \{  
         current += addition;  
     \}

public void setCurrent(long current) \{  
         this.current = current;  
     \}

public long getCurrent() \{  
         return current;  
     \}

public void setFirst(long first) \{  
         this.first = first;  
         current = first;  
     \}

public long getFirst() \{  
         return first;  
     \}

public void setInterval(long interval) \{  
         this.interval = interval;  
     \}

public long getInterval() \{  
         return interval;  
     \}

public void setLast(long last) \{  
         this.last = last;  
     \}

public long getLast() \{  
         return last;  
     \}

// Public --------------------------------------------------------  
     public long getNext() \{  
         long next = current;  
         current += interval;

if (wrap && (current > last)) \{  
             current -= ((1 + last) - first);  
         \}

return next;  
     \}

public long getPrevious() \{  
         current -= interval;

if (wrap && (current < first)) \{  
             current += (last - first + 1);  
         \}

return current;  
     \}

public void setWrap(boolean wrap) \{  
         this.wrap = wrap;  
     \}

public boolean isWrap() \{  
         return wrap;  
     \}

public boolean hasNext() \{  
         return ((last == -1) || wrap) ? true : (current <= last);  
     \}

public Object next() \{  
         return new Long(getNext());  
     \}

public void remove() \{  
         // Do nothing

**//项目中的应用**

<s:set name="number" value="\#parameters.num" />   //num是从前一个页面中传递过来的参数  
      <s:bean name="org.apache.struts2.util.Counter" id="counter">  
        <s:param name="first" value="2" />  
        <s:param name="last" value="%\{\#number\}" />  
        <s:iterator>    
              <s:property/>

</s:iterator>  
     </s:bean>

[http_www.apache.org_licenses_LICENSE-2.0]: http://www.apache.org/licenses/LICENSE-2.0