import java.io.BufferedInputStream;      import java.io.BufferedReader;      import java.io.File;      import java.io.FileInputStream;      import java.io.FileWriter;      import java.io.IOException;      import java.io.InputStreamReader;            public class FileSplit      {             public static void main(String[] args) throws IOException          {              long timer = System.currentTimeMillis();              int bufferSize = 20 * 1024 * 1024;//设读取文件的缓存为20MB                            //建立缓冲文本输入流              File file = new File("/media/Data/毕业设计/kdd cup/数据/userid_profile.txt");              FileInputStream fileInputStream = new FileInputStream(file);              BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream);              InputStreamReader inputStreamReader = new InputStreamReader(bufferedInputStream);              BufferedReader input = new BufferedReader(inputStreamReader, bufferSize);                            int splitNum = 112-1;//要分割的块数减一              int fileLines = 23669283;//输入文件的行数              long perSplitLines = fileLines / splitNum;//每个块的行数              for (int i = 0; i <= splitNum; ++i)              {                  //分割                  //每个块建立一个输出                  FileWriter output = new FileWriter("/home/haoqiong/part" + i + ".txt");                  String line = null;                  //逐行读取，逐行输出                  for (long lineCounter = 0; lineCounter < perSplitLines && (line = input.readLine()) != null; ++lineCounter)                  {                      output.append(line + "\r");                  }                  output.flush();                  output.close();                  output = null;              }              input.close();              timer = System.currentTimeMillis() - timer;              System.out.println("处理时间：" + timer);          }      }  

void largeFileIO(String inputFile, String outputFile) {        try {            BufferedInputStream bis = new BufferedInputStream(new FileInputStream(new File(inputFile)));            BufferedReader in = new BufferedReader(new InputStreamReader(bis, "utf-8"), 10 * 1024 * 1024);//10M缓存            FileWriter fw = new FileWriter(outputFile);            while (in.ready()) {                String line = in.readLine();                fw.append(line + " ");            }            in.close();            fw.flush();            fw.close();        } catch (IOException ex) {            ex.printStackTrace();        }