什么是类描述符？

是的，

Class

从API中：

此类的实例表示正在运行的Java应用程序中的类和接口。枚举是一种类，注释是一种接口。每个数组还属于一个反映为Class对象的类，该类对象由元素类型和维数相同的所有数组共享。原始Java类型（布尔型，字节型，字符型，短型，整型，长型，浮点型和双精度型）以及关键字void也都表示为

Class

对象。

这是一个简单使用

Class

static void describe(Class<?> clazz, String pad, String leadin) {    if (clazz == null) return;    String type =        clazz.isInterface() ? "interface" :        clazz.isArray() ? "array" :        clazz.isPrimitive() ? "primitive" :        clazz.isEnum() ? "enum" :        "class";    System.out.printf("%s%s%s %s ( %s )%n",        pad, leadin, type, clazz.getSimpleName(), clazz.getName());    for (Class<?> interfaze : clazz.getInterfaces()) {        describe(interfaze, pad + "   ", "implements ");    }    describe(clazz.getComponentType(), pad + "   ", "elements are ");    describe(clazz.getSuperclass(), pad + "   ", "extends ");}static void describe(Class<?> clazz) {    describe(clazz, "", "");    System.out.println();}public static void main(String[] args) {    describe(boolean[][].class);    describe(java.math.RoundingMode.class);    describe(java.util.ArrayList.class);    describe(void.class);}

上面的代码片段产生以下输出：

array boolean[][] ( [[Z )   implements interface Cloneable ( java.lang.Cloneable )   implements interface Serializable ( java.io.Serializable )   elements are array boolean[] ( [Z )      implements interface Cloneable ( java.lang.Cloneable )      implements interface Serializable ( java.io.Serializable )      elements are primitive boolean ( boolean )      extends class Object ( java.lang.Object )   extends class Object ( java.lang.Object )enum RoundingMode ( java.math.RoundingMode )   extends class Enum ( java.lang.Enum )      implements interface Comparable ( java.lang.Comparable )      implements interface Serializable ( java.io.Serializable )      extends class Object ( java.lang.Object )class ArrayList ( java.util.ArrayList )   implements interface List ( java.util.List )      implements interface Collection ( java.util.Collection )         implements interface Iterable ( java.lang.Iterable )   implements interface RandomAccess ( java.util.RandomAccess )   implements interface Cloneable ( java.lang.Cloneable )   implements interface Serializable ( java.io.Serializable )   extends class AbstractList ( java.util.AbstractList )      implements interface List ( java.util.List )         implements interface Collection ( java.util.Collection ) implements interface Iterable ( java.lang.Iterable )      extends class AbstractCollection ( java.util.AbstractCollection )         implements interface Collection ( java.util.Collection ) implements interface Iterable ( java.lang.Iterable )         extends class Object ( java.lang.Object )primitive void ( void )

API链接

• Class.getName()

  • 解释数组和基元的“ funky”名称

参考文献

• Java教程/反射API
  • 另请参阅： 有效的Java 2nd Edition，第53项：首选接口而不是反射
• JLS 15.8.2类文字