如何通过循环从datainputstream读取整个数据

Question

I've just started to work with data files in java and I don't know how to define loop to read whole file, not only a single line. I'm absolutely not sure am I thinking correctly::

public static void main(String[] args) throws IOException {
    DataInputStream dis = new DataInputStream(new FileInputStream("data.dat"));
    String name = null;
    do  {
        name = dis.readUTF();
        System.out.println(name);
    } while (!name.equals(null));
    dis.close();
}

When I'm trying this way, it shows me exactly what I want but with this kind of error:

szampon 8.80 120

Exception in thread "main" java.io.EOFException

zel 9.23 300

pasta 12.99 140 at java.base/java.io.DataInputStream.readUnsignedShort(DataInputStream.java:345) at java.base/java.io.DataInputStream.readUTF(DataInputStream.java:594) at java.base/java.io.DataInputStream.readUTF(DataInputStream.java:569) at com.company.Main.main(Main.java:13)

Process finished with exit code 1

Answer 1

Make this change

public static void main(String[] args) throws IOException {
DataInputStream dis = new DataInputStream(new FileInputStream("data.dat"));
String name = null;
do  {
    name = dis.readUTF();
    System.out.println(name);
} while ( dis.available() > 0);
dis.close();
}

The readUTF method will not return null , so you need to check if there any bytes available to read.

Answer 2

hope this will help you @Pawel

DataInputStream dis = new DataInputStream(new FileInputStream("data.dat"));
StringBuffer inputLine = new StringBuffer();
String tmp;
while ((tmp = dis.readLine()) != null) {
     inputLine.append(tmp);
     System.out.println(tmp);
}
dis.close();