Java-读取文件并拆分为多个文件

由于一个文件可能很大，因此每个拆分文件也可能很大。

例：

源文件大小：5GB

数字分割：5：目的地

档案大小：每个1GB（5个档案）

即使我们有这样的内存，也无法一口气读取这个大的拆分块。基本上，对于每个拆分，我们都可以读取一个固定大小

byte-array

NumSplits：10个MaxReadBytes：8KB

public static void main(String[] args) throws Exception    {        RandomAccessFile raf = new RandomAccessFile("test.csv", "r");        long numSplits = 10; //from user input, extract it from args        long sourceSize = raf.length();        long bytesPerSplit = sourceSize/numSplits ;        long remainingBytes = sourceSize % numSplits;        int maxReadBufferSize = 8 * 1024; //8KB        for(int destIx=1; destIx <= numSplits; destIx++) { BufferedOutputStream bw = new BufferedOutputStream(new FileOutputStream("split."+destIx)); if(bytesPerSplit > maxReadBufferSize) {     long numReads = bytesPerSplit/maxReadBufferSize;     long numRemainingRead = bytesPerSplit % maxReadBufferSize;     for(int i=0; i<numReads; i++) {         readWrite(raf, bw, maxReadBufferSize);     }     if(numRemainingRead > 0) {         readWrite(raf, bw, numRemainingRead);     } }else {     readWrite(raf, bw, bytesPerSplit); } bw.close();        }        if(remainingBytes > 0) { BufferedOutputStream bw = new BufferedOutputStream(new FileOutputStream("split."+(numSplits+1))); readWrite(raf, bw, remainingBytes); bw.close();        } raf.close();    }    static void readWrite(RandomAccessFile raf, BufferedOutputStream bw, long numBytes) throws IOException {        byte[] buf = new byte[(int) numBytes];        int val = raf.read(buf);        if(val != -1) { bw.write(buf);        }    }