Java随机生成前N个不重复的整数，java生成整数,import java.

Java随机生成前N个不重复的整数，java生成整数,import java.

import java.io.BufferedOutputStream;  import java.io.File;  import java.io.FileNotFoundException;  import java.io.FileOutputStream;  import java.io.IOException;  import java.io.OutputStream;  import java.util.Random;  /**  * 测试随机生成前N个不重复的整数  * @author Administrator  *  */  public class TestRandom {      public static void main(String[] args) {          randomNumber2File("e:/random.txt");      }      /**      * 根据提供的路径生成相应的随机数      * @param path      */      public static void randomNumber2File(String path){          File file = new File(path);          OutputStream os = null;          try {              os = new BufferedOutputStream(new FileOutputStream(file));              byte[] buf = new byte[20];              for(int j = 0; j < 100; j++){                  int[] arr = ranInt(9);                  StringBuffer sb = new StringBuffer();                  for(int i = 0; i < arr.length; i++){                      sb.append(arr[i]);                  }                  sb.append("\r\n");                  buf = sb.toString().getBytes();                  os.write(buf);              }          } catch (FileNotFoundException e) {              e.printStackTrace();          } catch (IOException e) {              e.printStackTrace();          }finally{              if(null != os){                  try {                      os.close();                  } catch (IOException e) {                      // TODO Auto-generated catch block                      e.printStackTrace();                  }              }          }      }      /**      * 利用随机生成数组的索引实现随机，并通过交换实现不重复      * @param n      * @return      */      public static int[] ranInt(int n) {          int[] arr = new int[n];          int i,randomIndex,temp;          for(i = 0; i < n; i++){              arr[i] = i+1;          }          for(i = 1; i < n; i++){              randomIndex = ranIndex(0, i);              //交换当前元素和生成的随机元素              temp = arr[i];              arr[i] = arr[randomIndex];              arr[randomIndex] = temp;          }          return arr;      }      public static int ranIndex(int start, int end){          Random r = new Random();          int result;          result = r.nextInt(end);          return result;        }  }