java 复制文件

小咪咪 2022-03-25 03:41 199阅读 0赞

java 进行文件复制，代码如下

/**
      * sourceFile 为被复制的文件, destinationFile 为目标文件
      * @param sourceFile
      * @param destinationFile
      * @throws IOException
      */
    public static void copyFile(File sourceFile, File destinationFile) throws IOException {
    		
        InputStream input = null;
        OutputStream output = null;
    		
        try {
    			
            input = new FileInputStream(sourceFile);  //从sourceFile文件中获得输入字节
            output = new FileOutputStream(destinationFile);
    			
            byte[] buf = new byte[1024];
            int bytesRead; 
    			
            while((bytesRead = input.read(buf)) > 0) {
                 output.write(buf, 0, bytesRead);
            }
    			
            } catch (FileNotFoundException e) {
                 e.printStackTrace();
            }finally {
                 input.close();
                 output.close();
            }	
    }

### 测试 ###

package nice;
    
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    
    public class DemoL {
    
    	public static void main(String[] args) throws IOException {
    
    		//File file = new File("E:\\谷歌下载\\20180318.txt");
    		
    		//File file = new File("E:\\谷歌下载\\作曲系初试科目选考表.xls");
    		
    		//File file = new File("E:\\谷歌下载\\timg123.jpg");
    		
    		File file = new File("E:\\谷歌下载\\命运还是巧合.mp3");
    		
    		
    		File dest = new File("C:\\Users\\Administrator\\Desktop\\file\\a.mp3");
    		
    		if(!dest.exists()) {
    			//dest.mkdirs();  //创建文件夹
    			dest.createNewFile();  // 创建文件
    			System.out.println("创建成功");
    		}
    		
    		
    		try {
    			copyFile(file, dest);
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    	
    	/**
    	 * sourceFile 为被复制的文件, destinationFile 为目标文件
    	 * @param sourceFile
    	 * @param destinationFile
    	 * @throws IOException
    	 */
    	public static void copyFile(File sourceFile, File destinationFile) throws IOException {
    		
    		InputStream input = null;
    		OutputStream output = null;
    		
    		try {
    			
    			input = new FileInputStream(sourceFile);  //从sourceFile文件中获得输入字节
    			output = new FileOutputStream(destinationFile);
    			
    			byte[] buf = new byte[1024];
    			int bytesRead; 
    			
    			while((bytesRead = input.read(buf)) > 0) {
    				output.write(buf, 0, bytesRead);
    			}
    			
    		} catch (FileNotFoundException e) {
    			e.printStackTrace();
    		}finally {
    			input.close();
    			output.close();
    		}
    		
    	}
    }

除此之外，还有其他封装好的方法可以直接调用

使用 Java NIO包下的 transferFrom 方法，进行复制

package nice.com.priactice;
    
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.nio.channels.FileChannel;
    
    public class DemoO {
    
    	public static void main(String[] args) throws IOException {
    		
    		File source = new File("E:\\谷歌下载\\答案_伍佰.mp3");
    		File dest = new File("C:\\Users\\Administrator\\Desktop\\file\\答案.mp3");
    		
    		copyFileUseFileChannels(source, dest);
    	}
    	
    	/**
    	 * source 为被复制的文件, dest 为目标文件
    	 * @param source
    	 * @param dest
    	 * @throws IOException
    	 */
    	public static void copyFileUseFileChannels(File source, File dest) throws IOException {
    		FileChannel inputChannel = null;    
    		FileChannel outputChannel = null;  
    		
    		try {
    			
    			inputChannel = new FileInputStream(source).getChannel();
    			outputChannel = new FileOutputStream(dest).getChannel();
    			
    			outputChannel.transferFrom(inputChannel, 0, inputChannel.size());
    		} catch (FileNotFoundException e) {
    			e.printStackTrace();
    		}finally {
    			inputChannel.close();
    			outputChannel.close();
    		}
    	}
    }

使用 Apache Commons IO 包提供的复制文件的方法

首先在项目中引入 commons-io jar 包

<dependency>
        <groupId>commons-io</groupId>
        <artifactId>commons-io</artifactId>
        <version>2.4</version>
    </dependency>

commons-io 使用代码如下

package com.demo;
    
    import java.io.File;
    import java.io.IOException;
    import org.apache.commons.io.FileUtils;
    
    public class DemoFileCopy {
    
    	public static void main(String[] args) throws IOException {
    		
    		File srcFile = new File("E:\\谷歌下载\\真的爱你独唱.mp3");
    		File destFile = new File("C:\\Users\\Administrator\\Desktop\\file\\真的爱你独唱.mp3");
    		
    		if(! destFile.exists()) {
    			destFile.createNewFile();
    		}
    
    		FileUtils.copyFile(srcFile, destFile);
    	}
    }