RandomAccessFile拆分合并文件

Posted 2020-08-17 woqiaoxun

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.io.SequenceInputStream;
import java.util.Vector;

public class RandonFileAccessTest {
    public static void main(String[] args) throws IOException {
       
        splitFile("test.txt");
        mergeFile();
        mergeFile2();
    }
    
    
    //拆分文件
    public static void splitFile(String path) throws IOException{
        InputStream is = new FileInputStream(path);
        int len=0;
        byte[] buff = new byte[1024];
        int i = 1;
        while((len=is.read(buff))!=-1){
            RandomAccessFile raf = new RandomAccessFile("raf"+i+".txt", "rw");//raf1.txt raf2.txt 一共只有两个文件
            raf.write(buff,0,len);
            raf.close();
            i++;
        }
        is.close();
    }
    
　　//合并文件
    public static void mergeFile() throws IOException{
        RandomAccessFile raf = new RandomAccessFile("raf3.txt", "rw");
        InputStream is = null;
        for(int i=1;i<3;i++){
            int len=0;
            is = new FileInputStream("raf"+i+".txt"); //一共就两个文件
            byte[] buff = new byte[1024];
            while((len=is.read(buff))!=-1){
                raf.write(buff,0,len);
            }
        }
        
        is.close();
        raf.close();
    }
    
　　//另一种方式的合并文件
    public static void mergeFile2() throws IOException{
        RandomAccessFile raf = new RandomAccessFile("raf4.txt", "rw");
        InputStream is = null;
        
        Vector<InputStream> vt = new Vector<InputStream>();
        
        
        for(int i=1;i<3;i++){
            is = new FileInputStream("raf"+i+".txt");//raf1.txt raf2.txt
            vt.addElement(is);
        }
        SequenceInputStream sis = new SequenceInputStream(vt.elements());
        
        int len=0;
        byte[] buff = new byte[1024];
        while((len=sis.read(buff))!=-1){
            raf.write(buff,0,len);
        }
        
        sis.close();
        is.close();
        raf.close();
    }
}