java如何实现数值型二维数组和txt文件间的读存

Question

现有一数值型二维数组 double[][] value = new double[][] {
 { 5, 9, 2 },
                                     { 3, -4, 5 },
                                     { 2, 5, 1 },
                                     { -8, 3, 3 }};
现欲将其存入本地文件d:\\1.txt中，存入后再将数据读入 double[][] value，如何实现？ 

Answer 1

我自己写了一个，你参考下：
public class Test1 {
public static void main(String[] args) throws IOException {
double[][] value = new double[][] { { 5, 9, 2 }, { 3, -4, 5 },
{ 2, 5, 1 }, { -8, 3, 3,3 } };
File f = new File("d:/1.txt");
writeArray(value,f);

ArrayList<ArrayList<Double>> readArray = readArray(f);
System.out.println(readArray);
}

public static ArrayList<ArrayList<Double>> readArray(File f){
ArrayList<ArrayList<Double>> arrList=new ArrayList<ArrayList<Double>>();
try {
FileReader fr = new FileReader(f);
BufferedReader br = new BufferedReader(fr);
String line="";
while((line = br.readLine())!=null){
String[] split = line.split(",");
ArrayList<Double> list=new ArrayList<Double>();
for(String str:split){
list.add(Double.parseDouble(str));
}
arrList.add(list);
}
br.close();
fr.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return arrList;
}

public static void writeArray(double[][] arr,File file){
try {
FileWriter fw = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(fw);
for (double[] v : arr) {
for (double d : v) {
bw.write(String.valueOf(d)+",");
}
bw.newLine();
}
bw.close();
fw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}如果你实在想返回二维数组的话，就自己写个转换的函数

Answer 2

import java.io.*;
public class Test{
   private static double[][] value = new double[][] { 
                                    { 5, 9, 2 }, 
                                    { 3, -4, 5 }, 
                                    { 2, 5, 1 }, 
                                    { -8, 3, 3 }
                                   }; 
   public static void write(String filepath)throws Exception{
        OutputStream out=new FileOutputStream(filepath);
        ObjectOutputStream oout=new ObjectOutputStream(out);
        oout.writeObject(value); 
   } 
   public static double[][] read(String filepath)throws Exception{
        InputStream in=new FileInputStream(filepath);
        ObjectInputStream oin=new ObjectInputStream(in);
        return (double[][])(oin.readObject());
   }
   public static void print(double[][] arr){
      if(arr==null){
           System.out.println("数组为空!");
           return;
      }
      int row=arr.length;
      int col=arr[0].length;
      //System.out.println("row="+row+",col="+col);
      System.out.println("{");
      for(int i=0;i<row;i++){
          System.out.print("{");
          for(int j=0;j<col;j++){
             System.out.print(arr[i][j]+" ");
          }
          System.out.print("}");
          System.out.println(); 
      }
      System.out.println("}");
   }
   public static void main(String args[])throws Exception{
       String filepath="d:\\1.txt";
       write(filepath);
       double[][] readResult=read(filepath);
       print(readResult);   } 
}

Answer 3

程序确实写的不错，学习学习，谢谢了。 不过为什么在将数组内容写入d:\\1.txt中后，显示的是乱码： ur [[D黔dgE  xp   ur [D>玞Z  xp   @      @"      @       uq ~    @      @      @      uq ~    @       @      ??      uq ~    @       @      @