java中的clon()和cloneable接口浅析
The clone( ) method generates a duplicate copy of the object on which it is called. Only classes that implement the Cloneable interface can be cloned.
...clone()产生了一个调用它的对象的复制;只有实现了Cloneable接口的类才可以被复制。
The Cloneable interface defines no members. It is used to indicate that a class allows a bitwise copy of an object (that is, a clone ) to be made. If you try to call clone( ) on a class that does not implement Cloneable , a CloneNotSupportedException is thrown. When a clone is made, the constructor for the object being cloned is not called. A clone is simply an exact copy of the original.
Cloneable 接口没有定义任何成员。它用来指明一个类可以逐位复制一个对象。如果你试图对一个没有实现cloneable接口的类调用clone()方法，一个CloneNotSupportedException 就会抛出。在复制时，被复制的对象的构造器并没有被调用。复制对象就是原来对象的拷贝。
Cloning is a potentially dangerous action, because it can cause unintended side effects. For example, if the object being cloned contains a reference variable called obRef, then when the clone is made, obRef in the clone will refer to the same object as does obRef in the original. If the clone makes a change to the contents of the object referred to by obRef, then it will be changed for the original object, too. Here is another example. If an object opens an I/O stream and is then cloned, two objects will be capable of operating on the same stream. Further, if one of these objects closes the stream, the other object might still attempt to write to it, causing an error.
复制是一种存在潜在危险的行为，因为它会引起一些意想不到的负作用。例如，如果被复制的对象包含一个名为 obRef 引用变量，在复制时，复制对象的 obRe和f 原来对象的 obRef 都会指向同一个对象。如果复制对象对 obRef 指向的对象的内容做出一些改变，对于原来对象来说，也就相当于它也被改变了。还有另一个例子，如果一个操作I/O流的对象被复制了，这两个对象都能对同一I/O流进行操作。进一步说，如果它们两个中的一个关闭�
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代码如下：
以下为引用的内容：
package com.example.pinyin.demo2;
import net.sourceforge.pinyin4j.PinyinHelper;
import net.sourceforge.pinyin4j.format.HanyuPinyinCaseType;
import net.sourceforge.pinyin4j.format.HanyuPinyinOutputFormat;
import net.sourceforge.pinyin4j.form ......
最佳答案
1. 编写范例文档
public class TestNative
{
private native static int Max(int a,int b);
public static void main(String[] args)
{
System.out.println(Max(4,5));
}
static
{
System.loadLibrary("VCdll");
}
}
其中
LoadLibrary中的DLL文件名称可以 ......
最近要重新学习Java，找个例子来实践，在网上找了很多例程来看，自己重新编写了一个贪食蛇的例子，记在这里。
1.SnakeModel.java
import java.util.Observable;
import java.util.LinkedList;
import java.util.Arrays;
import java.util.Random;
import javax.swing.*;
//Observable类一般代表数据，实现接口Runna ......
上次談過了使用iText產生PDF檔，這次換成來談談使用JExcel來產生EXCEL檔的方法。
首先，先到他的SourceForge主頁面download相關的API檔案。
http://sourceforge.net/projects/jexcelapi/
或
http://www.andykhan ......
