随机流-RandomAccessFile

RandomAccessFile 基本操作

案例

import java.io.*;public class TestMain09 {public static void main(String[] args) throws Exception {insert("D:\\home\\product\\aa.txt",2,"ni");}public static   void   insert(String filename,long pos,String insertContent) throws Exception {File file = new File("D:\\home\\product\\aa.txt");RandomAccessFile raf = null;File tmp =new File("D:\\home\\product\\bb.txt");FileOutputStream tmpOut = null;FileInputStream tmpIn = null;//   tmp.deleteOnExit();raf = new RandomAccessFile(filename,"rw");tmpOut = new FileOutputStream(tmp);tmpIn = new FileInputStream(tmp);raf.seek(pos);byte[] bbuf = new byte[64];int hasRead = 0;//使用循环方式读取插入点后的数据while ((hasRead = raf.read(bbuf)) > 0) {System.out.println(hasRead);//将读取的数据写入临时文件tmpOut.write(bbuf, 0, hasRead);}//----------下面代码插入内容----------//把文件记录指针重新定位到pos位置raf.seek(pos);//追加需要插入的内容raf.write(insertContent.getBytes());//追加临时文件中的内容while ((hasRead = tmpIn.read(bbuf)) > 0) {System.out.println(hasRead);raf.write(bbuf, 0, hasRead);}}
}

随机流可以做断点续传和指定位置读取文件或插入内容

可参考