【java】文件复制的简单实现

 1 package 文件操作;
 2 
 3 import java.io.File;
 4 import java.io.FileInputStream;
 5 import java.io.FileOutputStream;
 6 import java.io.IOException;
 7 import java.io.InputStream;
 8 import java.io.OutputStream;
 9 
10 public class TestCopy {
11     public static void main(String[] args) throws IOException {
12         copy("D:\\com\\test.txt","C:\\com\\dest.txt");
13     }
14     public static void copy(String source,String dest) throws IOException{
15         File fileS=new File(source);
16         File fileD=new File(dest);
17         if(fileS.exists()){
18             InputStream in=new FileInputStream(fileS);
19             int len=(int)fileS.length();
20             byte[] b=new byte[len];
21             in.read(b);//一次性读入
22             in.close();            
23             
24             if(!(fileD.exists())){                
25                 fileD.getParentFile().mkdirs();
26                 fileD.createNewFile();                
27             }
28             OutputStream out=new FileOutputStream(fileD);
29             out.write(b);//一次性写出
30             out.close();
31         }else{
32             System.out.println(source+"文件不存在！");
33         }    
34     }
35 }