不知道這樣的叫法對(duì)不對(duì)，所以對(duì)亂序兩字加了個(gè)引號(hào)。代碼目的是把文本文件里以行為單位的數(shù)據(jù)隨機(jī)排序后存到另一個(gè)文件，速度還可以，所貼上來(lái)。測(cè)試30萬(wàn)行處理時(shí)間為550ms以內(nèi)。
import java.io.*;
import java.util.Calendar;
public class SortTxt {
public static void main(String[] args){
Calendar frontDate =Calendar.getInstance();
try{
FileInputStream fis = new FileInputStream("c:/a.txt");
BufferedWriter wr = new BufferedWriter(new FileWriter("c:/b.txt"));
byte[] buf = new byte[fis.available()];
fis.read(buf,0,fis.available());
String str = new String(buf);
fis.close();
String[] array = str.split("\r\n");
StringBuffer sb = new StringBuffer();
sb = randomSortString(array);
wr.write(sb.toString());
wr.flush();
wr.close();
} catch (Exception e) {
e.printStackTrace();
}
Calendar rearDate = Calendar.getInstance();
System.out.println("run time: "+(rearDate.getTimeInMillis() - frontDate.getTimeInMillis())+" ms");
}
public static StringBuffer randomSortString(String[] strs) {
int size = strs.length;
StringBuffer sb = new StringBuffer();
for(int i=0;i<strs.length;i++){
int rd = (int)(Math.random()*size);
sb.append(strs[rd]+"\r\n");
strs[rd] = strs[size-1];
size--;
}
return sb;
}
}