IO stream operation three: use byte array stream to achieve file copy

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * File copy using byte array stream
 * 1, file ---> byte array
 * 2, byte array ---> file
 * @author pence
 * @date December 28, 2017
 */
public class MyIO3 {

	public static void main(String[] args) throws IOException {

		// get content from file and save to byte array
		byte[] data = getBytesFromFile("C:/software/workspace/workspace/Test/src/test/a.txt");
		System.out.println(new String(data,"gbk"));
		
		//write byte array contents to file
		toFileFromByteArray(data, "C:/software/workspace/workspace/Test/src/test/b.txt");
		
	}
	
	/**
	 * Read byte array content and output to file
	 * @param src
	 * @param destPah
	 * @throws IOException
	 */
	public static void toFileFromByteArray(byte[] src, String destPath) throws IOException{
		
		//1. Create source
		File dest = new File(destPath);
		
		//2. Select the stream
		InputStream is = new BufferedInputStream(new ByteArrayInputStream(src));//Byte array input stream
		OutputStream os = new BufferedOutputStream(new FileOutputStream(dest));//File output stream
		
		//3. Operation
		byte[] flash = new byte[1024];
		int len ​​= 0;
		while(-1 != (len=is.read(flash))){
			// output to file
			os.write(flash, 0, len);
		}
		os.flush();
		
		//4. Close the stream
		os.close();
		is.close();
	}
	
	/**
	 * Read file contents and output to byte array
	 * @param srcPath
	 * @return
	 * @throws IOException
	 */
	public static byte[] getBytesFromFile(String srcPath) throws IOException{
		
		//1. Create source
		File src = new File(srcPath); //source file
		byte[] dest = null; //destination array
		
		//2. Select the stream
		InputStream is = new BufferedInputStream(new FileInputStream(src)); //Buffered byte input stream
		ByteArrayOutputStream bos = new ByteArrayOutputStream(); //byte array output stream
		
		//3. Operation
		int len ​​= 0;
		byte[] flash = new byte[1024];
		while(-1 != (len=is.read(flash))){
			// output to byte array
			bos.write(flash, 0, len);
		}
		bos.flush();
		//retrieve data
		dest = bos.toByteArray(); //The new method is called here, so polymorphism cannot be used when creating objects
		
		//4. Close the stream
		bos.close();
		is.close();
		
		return dest;
	}

}