利用RandomAccessFile类在指定文件指定位置插入内容

package File;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;

/*利用RandomAccessFile类在指定文件指定位置插入内容。*/

public class InsertContent {
	public static void insert(String fileName, long pos, String insertContent)
			throws IOException {
		File tmp = File.createTempFile("tmp", null);
		tmp.deleteOnExit();
		try (RandomAccessFile raf = new RandomAccessFile(fileName, "rw");
				FileOutputStream tmpOut = new FileOutputStream(tmp);
				FileInputStream tmpIn = new FileInputStream(tmp)) 
		{
			raf.seek(pos);
			byte[] buf = new byte[64];
			int hasRead = 0;
			while((hasRead = raf.read(buf))>0)
			{
				tmpOut.write(buf, 0 ,hasRead);
			}
			
			raf.seek(pos);
			raf.write(insertContent.getBytes());
			while((hasRead = tmpIn.read(buf))>0)
			{
				raf.write(buf,0,hasRead);
			}
		}
	}

	public static void main(String[] args) throws IOException
	{
		insert("./src/File/InsertContent.java",45,"插入内容!\n");
		
	}
}