位图排序

 1 import java.io.*;
 2 import java.util.*;
 3 public class Main {
 4     
 5     
 6 public static void main(String[] argc) throws IOException{
 7 
 8         Main test = new Main();
 9         String largeFileName = "d:\\File_test\\old.txt";
10         String destlargeFileName = "d:\\File_test\\new.txt";
11         test.perform(largeFileName, 100, destlargeFileName,true);
12 }
13     
14 
15 private BitSet bits;
16 public void perform( String largeFileName,int total, String destLargeFileName,boolean asc) throws IOException {
17 System.out.println("BitmapSort Started.");
18  long start = System.currentTimeMillis();
19  bits = new BitSet(total);
20  FileWriter fw=new FileWriter(new File(destLargeFileName));
21  BufferedWriter  largeOut=new BufferedWriter(fw);
22  File fr = new File(largeFileName);
23  BufferedReader largeIn = new BufferedReader(new FileReader(fr));
24  
25 // OutputStreamWriter osw=new OutputStreamWriter(fos, "UTF-8");
26 //BufferedWriter  bw=new BufferedWriter(osw);
27  Integer data;
28  int off = 0;
29  try {
30  while (true) {
31  String Data = largeIn.readLine();
32  if (Data == null)
33  break;
34  data = Integer.parseInt(Data);
35  int v = data;
36  set(v);
37  off++;
38  }
39  largeIn.close();
40  int size = bits.size();
41  System.out.println(String.format("lines : %d ,bits : %d", off, size));
42  if(asc) {
43      for (int i = 0; i < size; i++) {
44      if (get(i)) {
45          largeOut.write(String.valueOf(i)+"\n");
46          largeOut.write("\t\n");
47      }
48      }
49  }
50  largeOut.close();
51  long stop = System.currentTimeMillis();
52  long elapsed = stop - start;
53  System.out.println(String.format("BitmapSort Completed.elapsed : %dms",elapsed));
54  }
55  finally {
56  largeIn.close();
57  largeOut.close();
58      } 
59  }
60 
61 private void set(int i) {
62  bits.set(i);
63  }
64 private boolean get(int v) {
65  return bits.get(v);
66  }
67 }