java和python二进制文件不能直接读取的解决方案

前一阵在做一个项目时，会用到java和python，上下游的关系（java写，python读），但是发现两者的二进制文件无法直接读取，后来发现是由于编码的原因，比如在写入int时，一个是从左到右开始编码，一个是从右到左，所以无法直接读取，因此可以自定义一个写入方法，继承自DataOutputStream来实现

//具体方法就是通过移位来更改写入顺序，使得python能够读取
public class inv_DataOutputStream extends DataOutputStream {
    public inv_DataOutputStream(DataOutputStream out) throws IOException
    { super(out); }
	//写入int的方法
    public final void inv_writeInt(int v) throws IOException {
        out.write((v >>> 0) & 0xFF);
        out.write((v >>> 8) & 0xFF);
        out.write((v >>>16) & 0xFF);
        out.write((v >>>24) & 0xFF);
    }
	//写入long的方法
    private byte writeBuffer[] = new byte[8];
    public final void inv_writeLong(long v) throws IOException {
        writeBuffer[0] = (byte)(v >>> 0);
        writeBuffer[1] = (byte)(v >>> 8);
        writeBuffer[2] = (byte)(v >>> 16);
        writeBuffer[3] = (byte)(v >>> 24);
        writeBuffer[4] = (byte)(v >>> 32);
        writeBuffer[5] = (byte)(v >>> 40);
        writeBuffer[6] = (byte)(v >>> 48);
        writeBuffer[7] = (byte)(v >>> 56);
        out.write(writeBuffer, 0, 8);
    }
}

写好之后就可以直接调用了，强调一点如果写入float，使用的是

wr.inv_writeInt(Float.floatToIntBits(_float));

当时也研究了java读取python二进制的方法，虽然没用到，这里也分享给大家，原理类似，就不写注释了

public class inv_read_binary extends DataInputStream {
    public inv_read_binary(DataInputStream in) throws IOException
    { super(in); }

    public final int read_int() throws IOException {
        int ch1 = in.read();
        int ch2 = in.read();
        int ch3 = in.read();
        int ch4 = in.read();
        if ((ch1 | ch2 | ch3 | ch4) < 0)
            throw new EOFException();
        return ((ch1 << 0) + (ch2 << 8) + (ch3 << 16) + (ch4 << 24));
    }

    public final float read_float() throws IOException {
        return Float.intBitsToFloat(read_int());
    }

    private byte readBuffer[] = new byte[8];
    public final long read_long() throws IOException{
        readFully(readBuffer, 0, 8);
        return (((long)readBuffer[7] << 56) +
                ((long)(readBuffer[6] & 255) << 48) +
                ((long)(readBuffer[5] & 255) << 40) +
                ((long)(readBuffer[4] & 255) << 32) +
                ((long)(readBuffer[3] & 255) << 24) +
                ((readBuffer[2] & 255) << 16) +
                ((readBuffer[1] & 255) << 8) +
                ((readBuffer[0] & 255) << 0));
    }
}