struts标签介绍

1.<logic:equal> and so on比较标签
以下eg都是由一个servlet转发过来的
MyBean mb = new MyBean();
mb.setName("yc");
mb.setCount(200);
request.setAttribute("mybean",mb);
request.getRequestDispatcher("jsp1.jsp").forward(request,response);

eg1：<bean:define id="myint" value="100"/>//当前页面定义一个字符串
<logic:equal name="myint" value="100">
myint=100
</logic:equal>

eg2：<bean:define id="bean3" name="mybean" scope="request"/>//从request上获取bean
<logic:lessThan name="bean3" property="count" value="200.a">//比较bean的count属性和200.a
bean3 LessThan 200.a
</logic:lessThan>

注意：如果两个字符串都能够成功转为数字，则是比较数字的大小，否则像eg2就是比较字符串的大小

eg3：<bean:define id="bean1" name="mybean" property="name" scope="request"/>
<logic:equal name="bean1" value="yc">
name1=yc
</logic:equal>

eg4：<bean:define id="bean2" name="mybean" scope="request"/>
<logic:equal name="bean2" property="name" value="yc">
name2=yc
</logic:equal>

注意：eg3和eg4都是比较bean属性，只是写法不同

eg5：比较请求参数

<logic:equal parameter="id" value="150">
<bean:parameter id="myid" name="id"/>
parameter:<bean:write name="myid"/>=150
</logic:equal>

2.<logic:match>
查看指定字符串是否被包含
<logic:match name="" value="被包含字符串" location="start/end也可以不写，就是任意位置"/>

eg：<bean:define id="bean4" name="mybean" property="name" scope="request"/>
<logic:match name="bean4" value="y" location="start">
yc is start with bean4
</logic:match>

3.< logic:iterator>
a.遍历Vector等集合，value形式的
<logic:iterator id="每个集合的元素" name="集合在当前页面的绑定名" indexId="序号"
offset="起始位置，0开始" length="遍历长度"/>

前提： Vector v = new Vector();
v.add("dog");
v.add("girl");
v.add("bird");
v.add("cat");
request.setAttribute("myvector",v);
request.getRequestDispatcher("jsp1.jsp").forward(request,response);

eg1：<bean:define id="vector1" name="myvector" scope="request"/>
<logic:iterate id="element" name="vector1">
<bean:write name="element"/>
<br />
</logic:iterate>

eg2：<bean:define id="vector2" name="myvector" scope="request"/>
<logic:iterate id="element" name="vector2" indexId="index" offset="1" length="3">
<bean:write name="index"/>.<bean:write name="element"/><br />
</logic:iterate>

b.遍历Map等，key/value形式
只是输出的时候有所不同
<bean:write name="" property="key"/>输出元素的key部分
<bean:write name="" property="value"/>输出元素的value部分

前提： HashMap hm = new HashMap();
hm.put("yc","yuechen");
hm.put("tjs","tianjinsong");
hm.put("xc","xiaocen");
hm.put("xk","xukai");
request.setAttribute("mymap",hm);

eg：<bean:define id="map1" name="mymap" scope="request"/>
<logic:iterate id="element" name="map1" indexId="index">
<bean:write name="index"/>.<bean:write name="element" property="key"/>:<bean:write name="element" property="value"/><br />
</logic:iterate>

c.遍历map中的集合
双层iterator，内层iterator需要加入property="value"

前提： HashMap hm2 = new HashMap();
String[]asia = {"china","japan","korea"};
hm2.put("asia",asia);
String[]erop = {"greman","rasa","england"};
hm2.put("erop",erop);
String[]us = {"usa","canada"};
hm2.put("us",us);
request.setAttribute("country",hm2);

eg：<bean:define id="myc" name="country" scope="request"/>
<logic:iterate id="element" name="country" indexId="index">
<bean:write name="index"/>.<bean:write name="element" property="key"/><br />
<logic:iterate id="inelement" name="element" indexId="inindex" property="value">
-----<bean:write name="inindex"/>.<bean:write name="inelement"/><br />
</logic:iterate>
</logic:iterate>