（一） 在电脑D盘下创建一个文件为HelloWorld.txt文件，判断他是文件还是目录，在创建一个目
录IOTest,之后将HelloWorld.txt移动到IOTest目录下去；之后遍历IOTest这个目录下的文
件
为了提高代码的安全性，这里所有的异常，我都处理了，而不是抛出，如果想方便的话，可以都抛出。
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class Demo1 {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
File file = new File("C:\Users\junjiejie\Desktop\HelloWorld.txt");
File file4 = new File("C:\Users\junjiejie\Desktop\Haha.txt");
FileInputStream fileInputStream = null;
FileOutputStream fileOutputStream = null;
File file2 = null ;
try {
System.out.println(file.createNewFile());
System.out.println(file4.createNewFile());
if (file.isFile()) {
System.out.println("是文件！");
}else{
System.out.println("不是文件！");
}
file2 = new File("C:\Users\junjiejie\Desktop\IOTest");
System.out.println(file2.mkdir());
File file3 = new File("C:\Users\junjiejie\Desktop\IOTest\HelloWorld.txt");
System.out.println(file3.createNewFile());
fileInputStream = new FileInputStream(file);
fileInputStream = new FileInputStream(file4);
fileOutputStream = new FileOutputStream(file3);
byte[] b = new byte[1024];
while (fileInputStream.read(b) != -1) {
fileOutputStream.write(b);
}
} catch (IOException e) {
// TODO Auto-generated catch block
throw new RuntimeException(e);
}finally{
try {
fileOutputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
throw new RuntimeException(e);
}
try {
fileInputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
throw new RuntimeException(e);
}
file.delete();
file4.delete();
String[] arr= file2.list();
for (String string : arr) {
System.out.println(string);
}
}
}
}