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();
	}
}