随机访问文件

/**
 * 测试随机访问文件
 */
public class TestRandomAccessFile {
    
    @Test
    public void test1(){
        try {
            RandomAccessFile raf = new RandomAccessFile("d:\\111.txt","rw");
            //raf.seek(3);
            byte[] buf = new byte[2] ;
            int len = 0 ;
            while((len = raf.read(buf)) != -1){
                System.out.println(new String(buf,0,len));
            }
            raf.seek(raf.getFilePointer() - 1);
            //raf.skipBytes();
            len = 0 ;
            while((len = raf.read(buf)) != -1){
                System.out.println(new String(buf,0,len));
            }
            raf.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    /**
     * 设置文件大小
     */
    @Test
    public void testRafLength(){
        try {
            RandomAccessFile raf = new RandomAccessFile("d:\\222.txt","rw");
            raf.setLength(1024);
            raf.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    /**
     * 设置文件大小
     */
    @Test
    public void testRafConent(){
        try {
            RandomAccessFile raf = new RandomAccessFile("d:\\222.txt","rw");
            byte[] buf = new byte[10];
            raf.read(buf);
            System.out.println();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
        
}