struts2

一、iterator属性

iterator标签主要是用于迭代输出集合元素,如list set map 数组等,在使用标签的时候有三个属性值得我们关注

1. value属性:可选的属性,value属性是指一个被迭代的集合,使用ognl表达式指定,如果为空的话默认就是ValueStack栈顶的集合.
   2.id属性:可选属性, 是指集合元素的id
   3.status属性:可选属性,该属性在迭代时会产生一个IteratorStatus对象,该对象可以判断当前元素的位置,包含了以下属性方法:

int getCount(); 迭代元素个数

int getIndex(); 迭代元素当前索引

boolean getFirst(); 是否为第一个

boolean getEven(); 是否为偶

boolean getLast(); 是否最后一个

bolean getOdd(); 是否为奇

由于iteratorstatus对象并不是ognl的根对象因此访问需要加上 #访问如下例子:

<s:iterator value=”{’dd’,'bb’,'cc’}” status=”st”>

<s:if test=”#st.odd”>

<s:property value=”#st.index”/>

</s:if>

</s:iterator>

此外:iterator也可以迭代map对象,map对象中有几对key-value 就迭代几次,分别使用

<s:property value=”key”/>
<s:property value=”value”/>

输出即可.

案例如下（Struts2标签）：实现奇偶行不同颜色显示

JSP中结果集显示如下：

<s:iterator value="resultList" status="status">
<tr class="<s:if test="#status.even">row-even</s:if><s:else>row-odd</s:else>">
<td>
<s:property value=""/>
</td>
</tr>
</s:iterator>

样式表可以参考：

.row-even{background-color:#def7c2;}
.row-odd{background-color:#c8e7a6;}

除了使用#status.even判断是否偶数行外，还有其他几个属性可以使用：
1)status.odd 是否奇数行
2)status.count 当前行数
3)status.index 当前行的序号，从0开始
4)[#status.count=#status.index+1]
5)status.first 是否第一行
6)status.last 是否最后一行
7)status.modules(int) 当前行数取模

二、iterator的使用解析

1:jsp页面定义元素写法 数组或list

<s:iterator value="{'1','2','3','4','5'}" id='number'>
    <s:property value='#number'/>A
</s:iterator>

打印结果为: 1A2A3A4A5A
2:索引的用法
如果指定了status，每次的迭代数据都有IteratorStatus的实例，它有以下几个方法
int getCount()返回当前迭代了几个元素
int getIndex()返回当前元素索引
boolean isEven()当然的索引是否偶数
boolean isFirst()当前是否第一个元素
boolean isLast()
boolean isOdd()当前元素索引是否奇数


现在的索引是奇数为:

当前元素值：

3：遍历map
value可以直接定义为：
value=”#{“1”:”a”,”2”:”b”}”
每个元素以都好隔开。元素之间的key和value 冒号隔开
value也可以是数据栈里面的java.util.Map对象
遍历写法如下：

<s:iterator value="map" id="id" status="st">
     key : <s:property value='key'/>
     value:<s:property vlaue='value'/>
</s:iterator>

当然key 和value 都可以使java 的 Object
3：遍历数据栈.简单的List类，

List<Attr>
class Attr{String attrName;String getAttrName(){return "123";}}
<s:iterator value="label" id="id">
    <s:property value="#id.attrName" />
</s:iterator>

当然value 还可以写成 value=”%{label}” label可以有.操作
label的属性List 可以写成value=”%{label.list}” 相当于：getLabel().getList();
4：遍历2个list；
List attrN {color,size,style}
List attrV {red,20,gay}
这2个list的元素是一一对应的，一个attrN对应一个attrV

<s:iterator value="%{attrN }" id="id"   status="status">
index    is : <s:property value='status.index'/>
attrName is : <s:property value='id'/> or <s:property value='%{id}'/>
attrName is : <s:property value='%{attrV[#status.index]}'/>
</s:iterator>  

二、各种遍历用法总结

1.struts2遍历map小结

1)MapAction.java

import java.util.ArrayList;   
import java.util.HashMap;   
import java.util.List;   
import java.util.Map;  

import com.opensymphony.xwork2.ActionSupport 
import com.model.Student 
public class MapAction extends ActionSupport   
{   

    private Map<String,String> map;   

    private Map<String,Student> studentMap;   

    private Map<String,String[]> arrayMap;   

    private Map<String,List<Student>> listMap;   


    public String testMap()   
   {   
       map=new HashMap<String,String>();   
        map.put("1", "one");   
        map.put("2", "two");   

        studentMap=new HashMap<String,Student>();   
        studentMap.put("student1",new Student(new Long(1),"20034140201","张三1","男",25));   
        studentMap.put("student2",new Student(new Long(2),"20034140202","张三2","女",26));   
        studentMap.put("student3",new Student(new Long(3),"20034140202","张三3","男",27));   

        arrayMap=new HashMap<String,String[]>();   
        arrayMap.put("arr1", new String[]{"1","2003401","leejie","male","20"});   
        arrayMap.put("arr2", new String[]{"2","2003402","huanglie","male","25"});   
        arrayMap.put("arr3", new String[]{"3","2003403","lixiaoning","male","21"});   


        listMap=new HashMap<String,List<Student>>();   

        List<Student> list1=new ArrayList<Student>();   
       list1.add(new Student(new Long(1),"20034140201","张三1","男",25));   
        list1.add(new Student(new Long(2),"20034140202","张三2","男",25));   
        list1.add(new Student(new Long(3),"20034140203","张三3","男",25));   
        listMap.put("class1", list1);   

        List<Student> list2=new ArrayList<Student>();   
        list2.add(new Student(new Long(1),"20034140301","李四1","男",20));   
        list2.add(new Student(new Long(2),"20034140302","李四2","男",21));   
        list2.add(new Student(new Long(3),"20034140303","李四3","男",22));   
        list2.add(new Student(new Long(4),"20034140304","李四4","男",23));   
        listMap.put("class2", list2);   




        return SUCCESS;   

    }   

    public Map<String, String> getMap() {   
       return map;   
    }   

   public void setMap(Map<String, String> map) {   
        this.map = map;   
    }   

    public Map<String, Student> getStudentMap() {   
        return studentMap;   
    }   

    public void setStudentMap(Map<String, Student> studentMap) {   
        this.studentMap = studentMap;   
    }   

    public Map<String, String[]> getArrayMap() {   
       return arrayMap;   
   }   


    public void setArrayMap(Map<String, String[]> arrayMap) {   
        this.arrayMap = arrayMap;   
    }   


    public Map<String, List<Student>> getListMap() {   
        return listMap;   
    }   

    public void setListMap(Map<String, List<Student>> listMap) {   
        this.listMap = listMap;   
    }   


}  

2.testMap.jsp 
<%@ page contentType="text/html;charset=UTF-8" %>   
<%@ taglib prefix="s" uri="/struts-tags" %>   
<html>   
<head>   
<title>struts2中的map遍历总结</title>   
</head>   
<body>   
   <b>1.map中的value为String字符串</b><br>   
   <s:iterator value="map" id="column">   
   <s:property value="#column"/><br>   
   key: <s:property value="key"/><br>   
   value:<s:property value="value"/><br>   
   ******************************************<br>   
  </s:iterator>   

  <b>2.map中的value为Student对象</b>   
  <table border="1" width="50%"  cellspacing="0" cellpadding="0">   
    <tr>   
      <td>key=value</td>   
      <td>ID</td>   
      <td>num</td>   
      <td>name</td>   
      <td>sex</td>   
      <td>age</td>   
    </tr>   
    <s:iterator value="studentMap" id="column">   
    <tr>   
     <td><s:property value="#column"/></td>   
     <td><s:property value="value.id"/></td>   
     <td><s:property value="value.num"/></td>   
     <td><s:property value="value.name"/></td>   
     <td><s:property value="value.sex"/></td>   
     <td><s:property value="value.age"/></td>   
    </tr>   
    </s:iterator>   
  </table>   
  <p>   


  <b>3.map中的value为String数组</b>   
  <table border="1" width="50%" cellspacing="0" cellpadding="0">   
    <tr>   
      <td>key=value</td>   
      <td>ID</td>   
      <td>num</td>   
      <td>name</td>   
     <td>sex</td>   
      <td>age</td>   
    </tr>   
    <s:iterator value="arrayMap" id="column">   
    <tr>   
     <td><s:property value="#column"/></td>   
     <td><s:property value="value[0]"/></td>   
     <td><s:property value="value[1]"/></td>   
     <td><s:property value="value[2]"/></td>   
     <td><s:property value="value[3]"/></td>   
     <td><s:property value="value[4]"/></td>   
    </tr>   
    </s:iterator>   
  </table>   
  <p>   
  <b>4.map中的value为list集合</b>   
  <table border="1" width="50%"  cellspacing="0" cellpadding="0">   
    <tr>   
      <td>class</td>   
      <td>ID</td>   
      <td>num</td>   
      <td>name</td>   
      <td>sex</td>   
      <td>age</td>   
    </tr>   

   <1.<s:iterator value="listHashMap" id="listid">   
   <s:iterator value="#listid.value" id="listidsub">   
       <tr>   
            <td><s:property value="key"/></td>   
            <td><s:property value="id"/></td>   
           <td><s:property value="num"/></td>   
            <td><s:property value="name"/></td>   
            <td><s:property value="sex"/></td>   
           <td><s:property value="age"/></td>   
        </tr>   
    </s:iterator>   
</s:iterator>  
</table>   

2、普通属性

public String execute(){
   username = "zhangsan";
   password = "123";
}
<s:property value="username"/><br>
   <s:property value="password"/><br>

3、自定义对象

public String execute(){
  userInfo = new UserInfo();
  userInfo.setUsername("hhh");
  userInfo.setPassword("111");
}
<s:property value="userInfo.username"/><br>
   <s:property value="userInfo.password"/><br>

4、List（普通属性）

  public String execute(){
  list = new ArrayList<String>();
  list.add("aaa");
  list.add("bbb");
  list.add("ccc");
}
<s:iterator value="list" var="var">
    <s:property value="var"/><br>
   </s:iterator>
   或者：
   <s:iterator value="list">
    <s:property/><br>
   </s:iterator>

5、List（自定义对象属性）

public String execute(){
  list = new ArrayList<UserInfo>();
  UserInfo userInfo = new UserInfo();
  userInfo.setUsername("u1");
  userInfo.setPassword("p1");
  userInfo.setRoleInfo(new RoleInfo("r1"));
  list.add(userInfo);
  userInfo = new UserInfo();
  userInfo.setUsername("u2");
  userInfo.setPassword("p2");
  userInfo.setRoleInfo(new RoleInfo("r2"));
  list.add(userInfo);
}
<s:iterator value="list" var="var">
    <s:property value="#var.username"/>
    <s:property value="#var.password"/>
    <s:property value="#var.roleInfo.rolename"/><br>
</s:iterator>
或者：
<s:iterator value="list">
    <s:property value="username"/>
    <s:property value="password"/>
    <s:property value="roleInfo.rolename"/><br>
</s:iterator>

6、数组（普通属性）

public String execute(){
  strs = new String[2];
  strs[0] = "as";
  strs[1] = "asd";
}
<s:iterator value="strs">
    <s:property/><br>
   </s:iterator>

或者：

<s:iterator value="strs" var="var">
    <s:property value="var"/><br>
   </s:iterator>

7、数组（自定义对象属性）

public String execute(){
  strs = new UserInfo[2];
  UserInfo userInfo = new UserInfo();
  userInfo.setUsername("u11");
  userInfo.setPassword("11");
  strs[0] = userInfo;
  userInfo = new UserInfo();
  userInfo.setUsername("u22");
  userInfo.setPassword("22");
  strs[1] = userInfo;
}
<s:iterator value="strs">
    <s:property value="username"/>
    <s:property value="password"/><br>
   </s:iterator>
或者：
<s:iterator value="strs" var="var">
    <s:property value="#var.username"/>
    <s:property value="#var.password"/><br>
</s:iterator>

8、数组（自定义对象属性）
**public String execute(){
strs = new UserInfo[2];
UserInfo userInfo = new UserInfo();
userInfo.setUsername(“u11”);
userInfo.setPassword(“11”);
userInfo.setRoleInfo(new RoleInfo(“r11”));
strs[0] = userInfo;
userInfo = new UserInfo();
userInfo.setUsername(“u22”);
userInfo.setPassword(“22”);
userInfo.setRoleInfo(new RoleInfo(“r22”));
strs[1] = userInfo;
}





或者：




**

9、Map（普通属性）

public String execute(){
  map = new HashMap<String,String>();
  map.put("k1", "v1");
  map.put("k2", "v2");
}
<s:iterator value="map" var="var">
    <s:property value="#var.key"/>
    <s:property value="#var.value"/><br>
</s:iterator>
或者：
<s:iterator value="map">
    <s:property value="key"/>
    <s:property value="value"/><br>
</s:iterator>

8、Map（自定义对象属性）
public String execute(){
  map = new HashMap<String,UserInfo>();
  UserInfo userInfo = new UserInfo();
  userInfo.setUsername("u1");
  userInfo.setPassword("p1");
  userInfo.setRoleInfo(new RoleInfo("r1"));
  map.put("k1", userInfo);
  userInfo = new UserInfo();
  userInfo.setUsername("u2");
  userInfo.setPassword("p2");
  userInfo.setRoleInfo(new RoleInfo("r2"));
  map.put("k2", userInfo);
}
<s:iterator value="map" var="var">
    <s:property value="#var.key"/>
    <s:property value="#var.value.username"/>
    <s:property value="#var.value.password"/>
    <s:property value="#var.value.roleInfo.rolename"/><br>
</s:iterator>
或者
<s:iterator value="map">
    <s:property value="key"/>
    <s:property value="value.username"/>
    <s:property value="value.password"/>
    <s:property value="value.roleInfo.rolename"/><br>
</s:iterator>

8、Map嵌套Map（自定义对象属性）
public String execute(){
  map = new TreeMap<String,Map<String,UserInfo>>();
  Map<String,UserInfo> innerMap = new TreeMap<String,UserInfo>();
  UserInfo userInfo = new UserInfo();
  userInfo.setUsername("u1");
  userInfo.setPassword("p1");
  userInfo.setRoleInfo(new RoleInfo("r1"));
  userInfo = new UserInfo();
  userInfo.setUsername("u11");
  userInfo.setPassword("p11");
  userInfo.setRoleInfo(new RoleInfo("r11"));
  innerMap.put("k1", userInfo);
  innerMap.put("k11", userInfo);
  map.put("key1", innerMap);
  //////////////////////////
  innerMap = new TreeMap<String,UserInfo>();
  userInfo = new UserInfo();
  userInfo.setUsername("u2");
  userInfo.setPassword("p2");
  userInfo.setRoleInfo(new RoleInfo("r2"));
  userInfo = new UserInfo();
  userInfo.setUsername("u22");
  userInfo.setPassword("p22");
  userInfo.setRoleInfo(new RoleInfo("r22"));
  innerMap.put("k2", userInfo);
  innerMap.put("k22", userInfo);
  map.put("key2", innerMap);
}
<s:iterator value="map" var="var">
    <s:iterator value="value">
     <s:property value="#var.key"/>
     <s:property value="key"/>
     <s:property value="value.username"/>
     <s:property value="value.password"/>
     <s:property value="value.roleInfo.rolename"/><br>
    </s:iterator>
</s:iterator>