【发布时间】：2017-08-12 12:13:58
【问题描述】：
在这个程序员中，我发现前 100 个中的素数。数字是 INT 格式，它们的总数是 DOUBLE 格式。我想读取那个文件，我只为 INT 数字做了，但我不知道怎么做它为双数。 代码如下：
package int1;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.DoubleBuffer;
import java.nio.IntBuffer;
import java.nio.LongBuffer;
import java.nio.channels.FileChannel;
public class int_upis {
public static void main(String[] args) {
File a = new File("C:\\Users\\Jovan\\Desktop\\Pisem.txt");
FileOutputStream fos = null;
try {
fos = new FileOutputStream(a);
} catch (Exception e) {
}
FileChannel ch = fos.getChannel();
ByteBuffer bff = ByteBuffer.allocate(100);
IntBuffer ibf = bff.asIntBuffer(); // Int type
DoubleBuffer db = bff.asDoubleBuffer(); // Double type
double p = 0;
for (int i = 1; i <= 100; i++) {
int t = 0;
for (int j = 1; j <= i; j++) {
if (i % j == 0) {
t = t + 1;
}
}
if (t < 3) {
p = p + 1; // number of Prime numbers
System.out.println(i);
ibf.put(i);
bff.position(4 * ibf.position());
bff.flip();
try {
ch.write(bff);
bff.clear();
ibf.clear();
} catch (IOException e) {
}
}
}
try {
db.put(p); //At the end of the txt-file i put double format of number (Number of Prime numbers)
bff.position(8*db.position());
bff.flip();
ch.write(bff);
System.out.println("File is writen with: " + ch.size());
ch.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
现在我尝试读取这个文件：
public class int_ispis {
public static void main(String[] args) throws IOException {
File a = new File("C:\\Users\\Jovan\\Desktop\\Pisem.txt");
FileInputStream fis = null;
try {
fis = new FileInputStream(a);
} catch (Exception e) {
}
FileChannel ch = fis.getChannel();
ByteBuffer bff = ByteBuffer.allocate(6 * 4);
这是放在 6 行数组中的一行质数（下面这一行）：
int[] niz = new int[6];
System.out.println("Pre flipa: " + bff.position() + " " + bff.limit());
System.out.println("++++++++++++++++++++++++++++++++++++");
while (ch.read(bff) != -1) {
bff.flip();
System.out.println();
System.out.println("Posle flipa: " + bff.position() + " " + bff.limit());
IntBuffer ib = bff.asIntBuffer();
System.out.println("IB: " + ib.position() + " " + ib.limit());
int read = ib.remaining();
System.out.println(read);
当它到达文件末尾时，它将双数作为整数并写入错误的数字（如何将整数与双数分开？）
ib.get(niz, 0, ib.remaining());
for (int i = 0; i < read; i++) {
System.out.print(niz[i] + " ");
}
System.out.println();
System.out.println("=================================");
ib.clear();
bff.clear();
}
}
}
【问题讨论】：
标签： java integer double binaryfiles mixed