RandomAccessFile操作文件

package file;

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


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 tmpInputStream = new FileInputStream(tmp)
            ){
            //  将记录指针移动文件末尾  追加内容
//            raf.seek(raf.length());
            
            // 将记录指针移动指定位置
            raf.seek(pos);
            
            byte[] bbuf = new byte[64];
        
            int hasRead = 0;
            
            StringBuffer sbf = new StringBuffer();
            
            while((hasRead = raf.read(bbuf)) > 0 ){
                tmpOut.write(bbuf, 0 , hasRead);
                sbf.append(new String(bbuf));
            }
            System.out.println(sbf.toString());
            
            raf.seek(pos);
            
            raf.write(insertContent.getBytes());
            
            while ((hasRead = tmpInputStream.read(bbuf)) > 0) {
                raf.write(bbuf , 0 , hasRead);
            }
        }
    }
    
    public static void main(String[] args) {
        try {
            insert("f:/new 1.txt", 45, "ajsdkjfksldjfkl");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}