package com.test;  import java.io.BufferedReader;  import java.io.BufferedWriter;  import java.io.FileNotFoundException;  import java.io.FileReader;  import java.io.FileWriter;  import java.io.IOException;  import java.util.Collections;  import java.util.Iterator;  import java.util.LinkedList;  import java.util.Random;  public class LargeMappedFiles {      /**       * 大数据排序合并       *        * @param args       */       public static void main(String[] args) throws IOException {        // 写入文件的路径         String filePath = "D:\\456";        // 切分文件的路径         String sqlitFilePath = "D:\\456\\123";        //数据的个数         int CountNumbers=10000000;        //子文件的个数         int CountFile=10;        //精度         int countAccuracy=30*CountFile;        long startNumber=System.currentTimeMillis();        // 写入大数据文件         WriteData(filePath,CountNumbers);        System.out.println("存储完毕");        // 将大数据文件切分到另外的十个小文件中         sqlitFileDate(filePath, sqlitFilePath,CountFile);        System.out.println("文件切割完毕！");        // 把每个文件的数据进行排序         singleFileDataSort(sqlitFilePath,CountFile);        System.out.println("每个子文件排序完毕！");        //精度调整，十个文件数据进行比较整合         deathDataFile(filePath,sqlitFilePath,countAccuracy,CountFile);        System.out.println("整合完毕");        long stopNumber=System.currentTimeMillis();        System.out.println("耗时"+(stopNumber-startNumber)/1000+"毫秒");       }       // 写入大数据文件        public static void WriteData(String path,int CountNumbers) throws IOException {        path = path + "\\12114.txt";        FileWriter fs = new FileWriter(path);        BufferedWriter fw=new BufferedWriter(fs);        for (int i = 0; i < CountNumbers; i++) {         fw.write(new Random().nextInt(Integer.MAX_VALUE) + "\r\n");        }        fw.close();        fs.close();       }       // 将大数据文件切分到另外的十个小文件中        public static void sqlitFileDate(String filepath, String sqlitPath,         int CountFile) throws IOException {        FileWriter fs = null;        BufferedWriter fw=null;        FileReader fr = new FileReader(filepath + "\\12114.txt");        BufferedReader br = new BufferedReader(fr); // 读取获取整行数据         int i = 1;        LinkedList WriterLists=new LinkedList();    //初始化文件流对象集合         LinkedList fwLists=new LinkedList();        for (int j = 1; j <= CountFile; j++) {          //声明对象           fs = new FileWriter(sqlitPath + "\\12" + j + ".txt",false);          fw=new BufferedWriter(fs);                    //将对象装入集合           WriterLists.add(fs);          fwLists.add(fw);        }        //判断是文件流中是否还有数据返回         while (br.ready()) {         int count=1;//初始化第一文件流          for (Iterator iterator = fwLists.iterator(); iterator.hasNext();) {          BufferedWriter type = (BufferedWriter) iterator.next();          if(i==count)//判断轮到第几个文件流写入数据了           {           //写入数据，跳出，进行下一个文件流，下一个数据的写入            type.write(br.readLine() + "\r\n");           break;          }          count++;         }         //判断是否到了最后一个文件流了          if (i >= CountFile) {          i = 1;         } else          i++;        }        br.close();        fr.close();        for (Iterator iterator = fwLists.iterator(); iterator.hasNext();) {         BufferedWriter object = (BufferedWriter) iterator.next();         object.close();        }        //遍历关闭所有子文件流         for (Iterator iterator = WriterLists.iterator(); iterator.hasNext();) {         FileWriter object = (FileWriter) iterator.next();         object.close();        }       }       // 把每个文件的数据进行排序        public static void singleFileDataSort(String path1,int CountFile) throws IOException {        LinkedList nums = null;        for (int i = 1; i <= CountFile; i++) {         nums = new LinkedList();         String path = path1 + "\\12" + i + ".txt";         try {          FileReader fr = new FileReader(path);          BufferedReader br = new BufferedReader(fr);          while (br.ready()) {           // 将读取的单个数据加入到集合里面            nums.add(Integer.parseInt(br.readLine()));          }          // 对集合进行排序           Collections.sort(nums);          // 将排序好的数据写入源文件           numberSort(nums, path);          br.close();          fr.close();         } catch (NumberFormatException e) {          e.printStackTrace();         } catch (FileNotFoundException e) {          e.printStackTrace();         } catch (IOException e) {          e.printStackTrace();         }        }       }       // 对每个文件数据进行排序，再写入源文件        public static void numberSort(LinkedList list, String path) {        try {         FileWriter fs = new FileWriter(path);         BufferedWriter fw=new BufferedWriter(fs);         for (Iterator iterator = list.iterator(); iterator.hasNext();) {          Object object = (Object) iterator.next();          fw.write(object + "\r\n");         }         fw.close();         fs.close();        } catch (IOException e) {         e.printStackTrace();        }       }       // 文件数据最终整合(精度调整)        public static void deathDataFile(String filepath, String sqlitFilePath1,         int countAccuracy, int CountFile) throws IOException {        LinkedList nums = new LinkedList();                                       //添加数据，进行排序         Object temp = null;                                                       // 记录每次排序剩下的最后一个数字         boolean ispass = false;        LinkedList ispasses = null;                                               //记录数据文件的状态信息         FileWriter fs = new FileWriter(filepath + "\\Sort.txt", false);           //创建文件流，以便整合的数据写入         BufferedWriter bw=new BufferedWriter(fs);        FileReader fr = null;                                                     //声明读取文件流         BufferedReader br = null;                                                 //声明BufferedReader         LinkedList WriterLists = new LinkedList(); // 初始化文件流对象集合         LinkedList WriterListFile = new LinkedList();        for (int j = 1; j <= CountFile; j++) {         // 声明对象，开启所有子文件流访问所有子文件的数据          fr = new FileReader(sqlitFilePath1 + "\\12" + j + ".txt");         //开启所有BufferedReader，方便下次的整行的读取          br = new BufferedReader(fr);         // 将所有 FileReader对象装入集合          WriterListFile.add(fr);         // 将所有 BufferedReader对象装入集合          WriterLists.add(br);        }        for (;;) {         // 将十个源文件的是否有数据情况存入集合，以方便后面做判断          ispasses = new LinkedList();         // 分别读取十个源文件的单个数据          for (Iterator iterator = WriterLists.iterator(); iterator.hasNext();) {          BufferedReader object = (BufferedReader) iterator.next();          Object obj = null;          while (object.ready()) {           //添加所有文件流的每次的数据            nums.add(Integer.parseInt(object.readLine().toString()));           break;          }          if (object.ready() == false)           ispasses.add("true");           //将各文件中的数据状态存入集合中          }         // 决断是否是第一次进来          if (nums.size() % countAccuracy == 0 && ispass == false) {          // 对集合进行排序           Collections.sort(nums);          // 接收最大的数据，其它的数据写入总排序文件           temp = numberSortData(nums, filepath, false, countAccuracy, bw);          //重新初始化集合           nums = new LinkedList();          // 添加上一组比较剩下的数据           nums.add(temp);          ispass = true;          // 记录源文件的数据数量，以便下次的遍历           continue;         }         if (ispass) {          if (nums.size() % countAccuracy == 1 && nums.size() > 1) {           // 对集合进行排序            Collections.sort(nums);           // 接收最大的数据，其它的数据写入总排序文件            temp = numberSortData(nums, filepath, true, countAccuracy,             bw);           nums = new LinkedList();           nums.add(temp);           continue;          }         }         // 记录下一组数据的位置          // 判断是不是十个文件都没有数据          if (ispasses.size() == CountFile) {          Collections.sort(nums);          temp = numberSortData(nums, filepath, true, countAccuracy, bw);          nums = new LinkedList();          break;         }        }        bw.close();        //关闭写入流         fs.close();        //关闭所有的BufferedReader         for (Iterator iterator = WriterLists.iterator(); iterator.hasNext();) {         BufferedReader object2 = (BufferedReader) iterator.next();         object2.close();        }        //关闭所有的FileReader         for (Iterator iterator = WriterListFile.iterator(); iterator.hasNext();) {         FileReader object = (FileReader) iterator.next();         object.close();        }       }       // 对数据进行排序,写入最终文件中(精度调整)        public static Object numberSortData(LinkedList list, String filePath,         boolean ispass, int countAccuracy,BufferedWriter fs) {        Object temp = 0;                                                        //记录最后一个值         int tempCount = 0;                                                      //记录写入的数据位置         try {         for (Iterator iterator = list.iterator(); iterator.hasNext();) {          Object object = (Object) iterator.next();          // 判断是否是最后一个数           if (tempCount == list.size() - 1) {           // 判断集合里面不足一百個數了            if (list.size() < countAccuracy + 1 && ispass) {            temp = null;           } else {            temp = object;            break;           }          }          // 写入数据源           fs.write(object + "\r\n");          // 记录数据的下标           tempCount++;         }        } catch (IOException e) {         e.printStackTrace();        }        return temp;       }  }