# 四、ReflectionType 类用于获取函数、类方法的参数或者返回值的类型。 ## **ReflectionType**类用于获取函数、类方法的参数或者返回值的类型。 ``` <pre class="calibre17">``` ReflectionType <span class="token3">{</span> <span class="token">/* 方法 */</span> public allowsNull <span class="token3">(</span> void <span class="token3">)</span> <span class="token3">:</span> bool <span class="token">//检查是否允许null</span> public isBuiltin <span class="token3">(</span> void <span class="token3">)</span> <span class="token3">:</span> bool <span class="token">//检查它是否是内置类型</span> public __toString <span class="token3">(</span> void <span class="token3">)</span> <span class="token3">:</span> string <span class="token3">}</span> ``` ```