JAVA#RandomAccessFile 札记

public class TESTRandomAccess {
    @Test
    public void mm() {
        try {
            RandomAccessFile rf1 = new RandomAccessFile(new File("C:\\Users\\Administrator\\IdeaProjects\\untitled\\kkkbbb.txt"), "r");
            RandomAccessFile rf2 = new RandomAccessFile(new File("C:\\Users\\Administrator\\IdeaProjects\\untitled\\kkkbbb.txt"), "rw");
            byte[] b = new byte[10];
            int length;
            while ((length = rf1.read(b)) != -1) {
                rf2.write(b, 0, length);
            }
            rf2.close();
            rf1.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    @Test
    public void gg() {//覆盖效果
        try {
            RandomAccessFile rf3 = new RandomAccessFile(new File("C:\\Users\\Administrator\\IdeaProjects\\untitled\\kkkbbb.txt"), "rw");
            rf3.seek(3);//seek方法，在第几位开始写；
            rf3.write("i love kobe".getBytes());
            rf3.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    @Test
    public void ggg(){//insert
        try {
            RandomAccessFile rf4 = new RandomAccessFile(new File("C:\\Users\\Administrator\\IdeaProjects\\untitled\\kkkbbb.txt"), "rw");
            rf4.seek(4);//seek方法，调整到第几位；
           String str=rf4.readLine();
            rf4.seek(4);
            rf4.write("xy".getBytes());
            rf4.write(str.getBytes());
            rf4.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    @Test
    public void gggg(){//insert
        try {
            RandomAccessFile rf5= new RandomAccessFile(new File("C:\\Users\\Administrator\\IdeaProjects\\untitled\\kkkbbb.txt"), "rw");
            rf5.seek(4);//seek方法，调整到第几位,在其后进行操作；
           byte[] b=new byte[10];
           int length;
           StringBuffer sb=new StringBuffer();
           while((length=rf5.read(b))!=-1){
            sb.append(new String(b,0,length));
           }
           rf5.seek(4);
           rf5.write("aisong".getBytes());
           rf5.write(sb.toString().getBytes());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}