java _io_随机读取读入流RandomAccessFile

Posted 2022-06-05

随机读取和写入流RandomAccessFile

支持读取和写入随机访问文件

RandomAccessFile raf=new RandomAccessFile(文件对象，读写模式);r只读，rw读和写

private File f;
//目的地
private String dir;
//所有分割后的文件存储路径
private List<String> list;
//每块大小
private int blockSize;
//块数
private int size;

public n(File f,String dir,int blockSize)

this.f=f;
this.dir=dir;
this.blockSize=blockSize;
this.list=new ArrayList<String>;

//初始化
private void init()

//总长度
long len=this.f.length();
//块数
this.size=(int)Math.ceil(len*1.0/blockSize);
//路径:
for(int i=0;i<size;i++)

this.list.add(this.dir+i+this.f.getName());

//分割:计算每一块的起始位置及大小
public void split()

public void t3(int i,int first,int real) throws IOException

RandomAccessFile raf=new RandomAccessFile(this.f,"r");
RandomAccessFile raf2=new RandomAccessFile(this.list.get(i),"rw");

raf.seek(first);//从第二个位置开始

byte[] flush=new byte[1024];
int len=-1;
while((len=raf.read(flush))!=-1)

    if(real>1024)
    
        raf2.write(flush,0,len);
        real-=1024;
    else
    

    raf2.write(flush,0,real);
    break;  //读取指定大小，读完退出

raf2.close();
raf.close();

public static void main(String[]args)