Java核心编程之文件随机读写类RandomAccessFile详解

package test;import java.io.File;import java.io.FileNotFoundException;import java.io.IOException;import java.io.RandomAccessFile;public class RandomAccess {   public static void main(String[] args) {  try {   File file = new File("C://img//666.txt");      //打开文件   RandomAccessFile randomAccess = new RandomAccessFile(file,"rwd"); //访问文件    Long lenth = randomAccess.length(); //获取文件长度   System.out.println("lenth:"+lenth);   randomAccess.seek(4); //设置指针位置      //读取文件   int c = randomAccess.read(); //读取一个字节   System.out.println("c:"+c);   System.out.println("c:"+(char)c); //转换为字符      byte[] b = new byte[3]; //读取字节数字，创建数组   randomAccess.read(b, 1, 2); //从指针1处读取两个字节写入数组b中   String s = new String(b); //转换为字符串   System.out.println("byte:"+s); //输出      //写入文件   File file2 = new File("C://img//777.txt");   if(!file2.getParentFile().exists()){    file2.getParentFile().mkdirs();   }    file2.createNewFile();   RandomAccessFile randomAccess2 = new RandomAccessFile(file2,"rwd"); //访问文件    randomAccess2.write(b); //写入字符数组      //关闭文件   randomAccess.close();   randomAccess2.close();     } catch (FileNotFoundException e) {   // TODO Auto-generated catch block   e.printStackTrace();  } catch (IOException e) {   // TODO Auto-generated catch block   e.printStackTrace();  }     }}