Java 解析二进制数据

Question

I have to parse some binary data in Java. Part of my sample file looks like this

00000000000000010000000000000100

This is 32 bits long and I would like to parse 16 bits as java short. SO I would expect the output be 1 and 4. Code I have written so far is

Path path = Paths.get("filePath");
byte[] b = Files.readAllBytes(path);

ByteBuffer buffer = ByteBuffer.wrap(b).order(ByteOrder.LITTLE_ENDIAN);
    buffer.rewind();
    ShortBuffer ib = buffer.asShortBuffer();
     System.out.println(b.length);
     System.out.println(ib.get());
     System.out.println(ib.get());

This is parsing each value a ascii. and I get the following output.

32
12336
12336

Can someone help me with this.

Thanks AM

Answer 1

Solved parsing the String

    Path path = Paths.get("filePath");
    List<String> lines = null;
    try {
        lines = Files.readAllLines(path);
    } catch (IOException e) {
        e.printStackTrace();
    }

    for (String line : lines) {
        System.out.println(Short.parseShort(line.substring(0, 16), 2));
        System.out.println(Short.parseShort(line.substring(16, 32), 2));
    }

Answer 2

According to your description, the binary data contains 2 fields, both of which are signed 16-bit int, and are stored in little-endian. Recommend a tool( FastProto ) that can help you quickly implement the above process.

import org.indunet.fastproto.annotation.*;

@DefaultEndian(EndianPolicy.Little)
public class MyData {
    @Int16Type(offset = 0)
    Short s1;
 
    @Int16Type(offset = 2)
    Short s2;
}


byte[] binary = ... // your binary

MyData data = FastProto.parse(binary, MyData.class);

System.out.println(data.s1); // output 1
System.out.println(data.s2); // output 4

Maybe you have noticed that FastProto describes the field information in binary data through annotations, which is very simple and efficient.

If the project can solve your problem, please give a star, thanks.

GitHub Repo: https://github.com/indunet/fastproto