Java代码
| /** * Created by IntelliJ IDEA. * User: leizhimin * Date: 2007-9-20 * Time: 19:52:01 * 测试类：分别克隆CloneFooA和CloneFooB类,并打印克隆前后的结果. */ public class CloneDemo { public static void main(String args[]) throws CloneNotSupportedException { //CloneFooA克隆前 CloneFooA fooA1 = new CloneFooA("FooA", 11); System.out.println("CloneFooA的对象克隆前对象fooA1值为: " + fooA1.getStrA() + "," + fooA1.getIntA()); //CloneFooA克隆后 CloneFooA fooA2 = (CloneFooA) fooA1.clone(); System.out.println("CloneFooA的对象克隆后对象fooA2值为: " + fooA2.getStrA() + "," + fooA2.getIntA()); //比较fooA1和fooA2内存地址 if (fooA1 == fooA2) System.out.println("比较fooA1和fooA2内存地址:相等!"); else System.out.println("比较fooA1和fooA2内存地址:不相等!"); System.out.println("-------------------------"); //CloneFooB克隆前 CloneFooB fooB1 = new CloneFooB(fooA1, new Double("33")); System.out.println("CloneFooB的对象克隆前对象fooB1值为: " + fooB1.getFooA().getStrA() + "," + fooB1.getFooA().getIntA() + " | " + fooB1.getDouB()); //CloneFooB克隆后 CloneFooB fooB2 = (CloneFooB) fooB1.clone(); System.out.println("CloneFooB的对象克隆前对象fooB2值为: " + fooB2.getFooA().getStrA() + "," + fooB2.getFooA().getIntA() + " | " + fooB2.getDouB()); if (fooA1 == fooA2) System.out.println("比较fooB1和fooB2内存地址:相等!"); else System.out.println("比较fooB1和fooB2内存地址:不相等!"); } } |
运行结果：
CloneFooA的对象克隆前对象fooA1值为: FooA,11
CloneFooA的对象克隆后对象fooA2值为: FooA,11
比较fooA1和fooA2内存地址:不相等!
-------------------------
CloneFooB的对象克隆前对象fooB1值为: FooA,11 | 33.0
CloneFooB的对象克隆前对象fooB2值为: FooA,11 | 33.0
比较fooB1和fooB2内存地址:不相等!
反面教材：
最后，我给出我上面提出到最后要给出的反面例子。
随便写一个，在CloneFooA 的基础上做了少许改动，内容如下：
Java代码
| public class CloneFooA implements Cloneable { private String strA; private int intA; public CloneFooA(String strA, int intA) { this.strA = strA; this.intA = intA; } public String getStrA() { return strA; } public void setStrA(String strA) { this.strA = strA; } public int getIntA() { return intA; } public void setIntA(int intA) { this.intA = intA; } /** * @return 创建并返回此对象的一个副本。 * @throws CloneNotSupportedException */ public Object clone() throws CloneNotSupportedException { //直接调用父类的clone()方法,返回克隆副本 return super.clone(); } /** * @return 返回运行时的对象 */ public CloneFooA getInstance(){ return this; } public static void main(String args[]){ CloneFooA fooA=new CloneFooA("aa",11); System.out.println(fooA.getStrA()+" "+fooA.getIntA()); CloneFooA fooA1=fooA.getInstance(); System.out.println(fooA1.getStrA()+" "+fooA1.getIntA()); if(fooA==fooA1) System.out.println("fooA和fooA1内存地址相等!"); System.out.println("-------------------------"); //改变后fooA或者fooA1中任何一个,看看另外一个是否会改变 fooA1.setStrA("bb"); System.out.println(fooA.getStrA()+" "+fooA.getIntA()); System.out.println(fooA1.getStrA()+" "+fooA1.getIntA()); if(fooA==fooA1) System.out.println("fooA和fooA1内存地址相等,改变fooA1后,fooA的值也跟着变化了"); } } |
运行结果：
aa 11
aa 11
fooA和fooA1内存地址相等!
-------------------------
bb 11
bb 11
fooA和fooA1内存地址相等，改变fooA1后，fooA的值也跟着变化了。
