JAVA读取矩阵文件,矩阵数据的文件格式为.bak,或grd,矩阵数据交换

package com.gsafety.weixin.utils;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class MatrixUtils {
    public static void main(String[] args) {
        String[][] arrs =new String[120][120];
        String[][] retArr=new String[120][120];
    
        try {
            File file =new File("E:\\test.bak");
            InputStreamReader is=new InputStreamReader(new FileInputStream(file));
            BufferedReader br =new BufferedReader(is);
            String line="";
            int n=0;
            while((line=br.readLine())!=null){
                String [] retline=line.split("\\s+");
                arrs[n] = retline;
                n++;
            }
            
            //实现矩阵上下对折
            for (int i = 0; i < retArr.length; i++) {
                for (int j = 0; j < retArr[i].length; j++) {
                    retArr[arrs.length-i-1][j]=arrs[i][j];
                }
            }
            File wfile =new File("E:\\test2.bak");
            OutputStreamWriter os=new OutputStreamWriter(new FileOutputStream(wfile));
            BufferedWriter bw =new BufferedWriter(os);
            for (int m = 0; m < retArr.length; m++) {
                StringBuilder sb=new StringBuilder();
                for (String str : retArr[m]) {
                    sb.append(str+" ");
                    
                }
                bw.write(sb.toString());
                bw.newLine();
            }
            bw.flush();
            bw.close();
            br.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }

}