<h2>遍历</h2>
<textarea class="form-control" cols="100" rows="10">
    <#list ruleList as vi>
        Code: ${vi.code}, Name: ${vi.name} <br>
    </#list>
</textarea>

<br>

<h2>嵌套遍历</h2>
<textarea class="form-control" cols="100" rows="10">
    <#list configurationList as vi>
        <h2>${vi.tbIndex}</h2>
        <ul>
            <#list vi.fieldList as vj>
                <li>${vj.name} - ${vj.remark}</li>
            </#list>
        </ul>
    </#list>
</textarea>

<h2>赋值指令</h2>
<textarea class="form-control" cols="100" rows="10">
    <#assign name = "Freemarker">
</textarea>

<br>

<h2>直接显示文本</h2>
<textarea class="form-control" cols="100" rows="10">
    Hello, ${name}!
</textarea>

<br>

<h2>遍历</h2>
<textarea class="form-control" cols="100" rows="10">
    <#assign users = [{"name": "Alice", "age": 25}, {"name": "Bob", "age": 30}]>
    <#list users as user>
        Name: ${user.name}, Age: ${user.age}
    </#list>
</textarea>

<br>

<h2>嵌套遍历</h2>
<textarea class="form-control" cols="100" rows="10">
    <#assign classes = [
        {"name": "班级A", "students": ["学生1", "学生2", "学生3"]},
        {"name": "班级B", "students": ["学生4", "学生5"]},
        {"name": "班级C", "students": ["学生6", "学生7", "学生8", "学生9"]}
    ]>
    <#list classes as class>
        <h2>${class.name}</h2>
        <ul>
            <#list class.students as student>
                <li>${student}</li>
            </#list>
        </ul>
    </#list>
</textarea>

<br>

<h2>判断数据不为空，再执行遍历 （如果序列不存在，直接遍历会报错）</h2>
<textarea class="form-control" cols="100" rows="10">
    <#if users2??>
        <#list users2 as user>
            ${user}
        </#list>
    </#if>
</textarea>

<br>

<h2>当序列没有数据项时，使用默认信息</h2>
<textarea class="form-control" cols="100" rows="10">
    <#assign users3 = []>
    <#list users3 as user>
        ${user} |
        <#else >
            用户数据不存在！
    </#list>
</textarea>

<br>

<h2>判断数据是否存在</h2>
<textarea class="form-control" cols="100" rows="10">
    <#assign list="">
    <#if list??>
        数据存在
        <#else >
            数据不存在
    </#if>
    <br>
    <#if list2??>
        数据存在
    <#else >
        数据不存在
    </#if>
</textarea>

<br>

<h2>遍历时，判断是否是第一个和最后一个</h2>
<textarea class="form-control" cols="100" rows="10">
    <#assign userLast = [{"name": "1Alice", "age": 25}, {"name": "2Bob", "age": 30}, {"name": "3Lilei", "age": 30}, {"name": "4June", "age": 30}]>
    <#list userLast as user>
        Name: ${user.name}, Age: ${user.age}
        
        <#if user_index = 0>
            <span>(第一个元素)</span>
        </#if>
        
        <#if user_has_next>
        <#else>
            <span>(最后一个)</span>
        </#if>
        
        <#if !user_has_next>
            (最后一个元素)
        </#if>
        
        <#if !user?has_next>
            <!-- 当前元素是最后一个元素 -->
            (这是最后一个元素)
        </#if>
        
    </#list>
</textarea>

<br>

<h2>条件判断</h2>
<textarea class="form-control" cols="100" rows="10">
    <#assign age = 15>
    <#if age gte 18>
        You are an adult.
    <#else>
        You are a minor.
    </#if>
</textarea>


<br>

<h2>Switch 判断</h2>
<textarea class="form-control" cols="100" rows="10">
    <#assign day = "Friday">
    <#switch day>
        <#case "Monday">
            Start of the week!
        <#case "Friday">
            Almost weekend!
        <#default>
            Just another day.
    </#switch>
</textarea>

<br>

<h2>判断字符串中是否包含子字符串</h2>
<textarea class="form-control" cols="100" rows="10">
    <#assign str = "Hello, World!">
    <#if str?contains("World")>
        The string contains "World".
    <#else>
        The string does not contain "World".
    </#if>
</textarea>

<br>

<h2>判断Set中是否包含某个键</h2>
<textarea class="form-control" cols="100" rows="10">
    <#assign sample = ["A","B","C","D"]>
    <#assign str1 = "E">
    <#assign str2 = "A">
    
    <#if sample?seq_contains("A")>
        The set contains "A".
    <#else>
        The set does not contain "A".
    </#if>
    
    ${sample?seq_contains(str1)?string("yes","no")} <!-- no -->
    ${sample?seq_contains(str2)?string("yes","no")} <!-- yes -->
</textarea>

<br>


<h2>判断Map中是否包含某个键</h2>
<textarea class="form-control" cols="100" rows="10">
    <#assign myMap = {"key1": "value1", "key2": "value2"}>
    <#if myMap?keys?seq_contains("key1")>
        The map contains the key "key1"
    <#else>
        The map does not contain the key "key1"
    </#if>
</textarea>

<br>


<h2>使用自定义方法</h2>
<textarea class="form-control" cols="100" rows="10">
    ${func.random(32)}
</textarea>