讀二進制文件(文件裏面是double型二進制數據,共32個字節,對應的十進制數是1.0,2.0,3.0,4.0)。把32字節的byte[]數組,每8個字節轉一個double,轉成了一個double列表。代碼如下:
import java.io.*;
import java.util.ArrayList;
/**
* @program: WordC
* @description: 讀二進制文件(文件裏面是double型二進制數據,共32個字節,對應的十進制數是1.0,2.0,3.0,4.0)。把32字節的byte[]數組,每8個字節轉一個double,轉成了一個double列表
* @author: chen
* @create: 2020-01-15 11:19
**/
public class ReadBin {
public static double bytes2Double(byte[] arr) {
long value = 0;
for (int i = 0; i < 8; i++) {
value |= ((long) (arr[i] & 0xff)) << (8 * i);
}
return Double.longBitsToDouble(value);
}
public static void main(String[] args) throws IOException {
File f= new File("F:\\GraduationDesign\\code_python\\small_d");
FileInputStream fis= new FileInputStream(f);
DataInputStream dis= new DataInputStream(fis);
byte[] by= new byte[32];
dis.read(by);
dis.close();
// String s= new String(by);
// System.out.println(s);
byte[] tem = new byte[8];
System.out.println(tem[0]+"-"+tem[1]);//0-0
ArrayList<Double> list= new ArrayList<>();
//int count=0;
for(int i=0;i<32;){
for(int j=0;j<8;++j){
tem[j]= by[i];
++i;
}
//System.out.println("----"+bytes2Double(tem));
list.add(bytes2Double(tem));
}
for(Double x: list){
System.out.print(x+" ");//1.0 2.0 3.0 4.0
}
}
}
上面寫了兩個for循環,還可以改進,用位運算,每8個字節,移位,具體的有時間的話你可以想一下~