java.lang.Class
来自：http://www.cnblogs.com/eflylab/archive/2007/03/22/684691.html一． Class类
1. Class对象描述了运行中的classes和interfaces。通过Class对象可以取得运行中的classes和interfaces的相关信息。见例子程序
2. 每个类都有一个相应的java.lang.Class对象。每个类的Class对象存储于编译后的类所在的文件中。所以，当JVM装载一个.class文件时就会装载一个Class对象。所以，一个类只有一个Class对象。
二． 如何获取一个类的Class对象
1． 通过Class.forName(classname)方法，该方法接收一个String参数，用以指定要生成哪个class的Class对象.，如Class.forName(“Dog”)。
2. 通过类字面常量来获得。
1) 字面常量的形式为：classname.class。如Dog.class。
2) 对于基本类，每种基本类型的外覆类都有一个名为TYPE的标准数据，能够产生一个指向相应的基本类型的Class对象的reference。如int.class等同于Integer.TYPE。
3. 通过Object.getClass()方法来获得。
例子程序：
<div style="padding-right: 5px; padding-left: 4px; font-size: 13px; padding-bottom: 4px; width: 98%; padding-top: 4px; background-color: #eeeeee; border: #cccccc 1px solid;">http://www.cnblogs.com/Images/OutliningIndicators/None.gifclass Dog
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockStart.gifhttp://www.cnblogs.com/Images/OutliningIndicators/ContractedBlock.gifhttp://www.cnblogs.com/Images/dot.gif{
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif String name;
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockEnd.gif}
http://www.cnblogs.com/Images/OutliningIndicators/None.gifclass test
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockStart.gifhttp://www.cnblogs.com/Images/OutliningIndicators/ContractedBlock.gifhttp://www.cnblogs.com/Images/dot.gif{
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif public static void main(String[] args) throws Exception
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.cnblogs.com/Images/OutliningIndicators/ContractedSubBlock.gif http://www.cnblogs.com/Images/dot.gif{
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif Dog dog = new Dog();
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif //Class 类的实例表示正在运行的 Java 应用程序中的类和接口
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif //我们通过下面语句取得 正在运行的Dog类
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif Class dogClass = dog.getClass();
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif String s = dogClass.getName();// s = Dog
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif Package p = dogClass.getPackage();//返回Dog类的包名
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif Dog dog2 = (Dog)dogClass.newInstance(); //创建此 Class 对象所表示的类的一个新实例（Dog）
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif dog2.name="yy";
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif System.out.println(dog2.name);
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif System.out.println(dog.name);
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif System.out.println(s);
http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif System.out.println(p);
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockEnd.gif}
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