java读取写入文件

为了明天的建模比赛，紧急测试了一下java读取写入文件的能力。主要是为了防止去年文件太大，MATLAB读取慢的问题。同时祝愿今年可以取得好成绩！

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

import org.junit.Test;

public class Readdat {

        @SuppressWarnings("resource")
        @Test
        public void datTest() throws IOException {
                File file = new File("C:\\genotype.dat");
                BufferedReader br = null;
                List<String[]> list = new ArrayList<>();
                br = new BufferedReader(new FileReader(file));
                String content = null;
                int i = 1;
                while (true) {
                        content = br.readLine();
                        if (content == null) {
                                break;
                        }
                        String[] ss = content.split(" ");
//                      System.out.println(content);
                        System.out.println(i++);
                        list.add(ss);
                }
                System.out.println("done");
        }
        
        @SuppressWarnings("resource")
        @Test
        public void datfastTest() throws IOException {
                File file = new File("C:\\genotype.dat");
                Scanner s = new Scanner(file); 
                List<String[]> list = new ArrayList<>();
                int j = 1;
                int i = 0;
                String[] ss = new String[9445];
                while (s.hasNext()) {
                        ss[i] = s.next();
                        if (i++ == 9444) {
                                i = 0;
                                list.add(ss);
                                ss = new String[9445];
                                System.out.println(j++);
                        }
                }
                System.out.println("done");
                
                //存入文件
                File newfile = new File("D:/newfile.dat");
                FileWriter fw = null;
                BufferedWriter writer = null;
                fw = new FileWriter(newfile);
                writer = new BufferedWriter(fw);
                for (int k = 0; k < list.size(); k++) {
                        for (int kk = 0; kk < 9445; kk++) {
                                writer.write(list.get(k)[kk].toString() + " ");
                        }
                        writer.newLine();
                }
                writer.flush();
                writer.close();
                fw.close();
        }
}