标签控制页面2

3、迭代标签<c:foreach items=”” var=””>

Jsp的页面：< c:foreach items="${list}" var="str">

${str}

</c:foreach>

Tld文件的描述：<tag>

<name>foreach</name>

<tag-class>com.hbsi.web.tag.ForEachTag</tag-class>

<body-content>scriptless</body-content>

<attribute>

<name>items</name>

<required>true</required>

<rtexprvalue>true</rtexprvalue>

</attribute>

<attribute>

<name>var</name>

<required>true</required>

<rtexprvalue>false</rtexprvalue>

</attribute>

</tag>

标签处理器：public class ForEachTag extends SimpleTagSupport {

private Object items;

private String var;

public void setItems(Object items) {

this.items = items;

}

public void setVar(String var) {

this.var = var;

}

@Override

public void doTag() throws JspException, IOException {

//得到集合对象

Collection collection=null;

if(items instanceof Map){

Map map=(Map)items;

//两列集合转换成单列;映射

collection=map.entrySet();

}else if(items instanceof Collection){

collection=(Collection)items;//集合

}else if(items.getClass().isArray()){

collection=new ArrayList();

int length=Array.getLength(items);

for(int i=0;i<length;i++){

collection.add(Array.get(items, i));

}

}

Iterator it=collection.iterator();

while(it.hasNext()){

Object obj=it.next();//一个元素

this.getJspContext().setAttribute(var,obj);

this.getJspBody().invoke(null);

}

}

}