如何在Java中从浮点数转换为4字节

Question

我还没有能够转换这样的东西:

byte[] b = new byte[] { 12, 24, 19, 17};

变成这样:

float myfloatvalue = ?;

谁能给我举个例子?

还如何将浮点数转回字节?

Answer 1

byte[] -> float

With ByteBuffer:

byte[] b = new byte[]{12, 24, 19, 17};
float f =  ByteBuffer.wrap(b).getFloat();

float -> byte[]

反向操作(知道上面的结果):

float f =  1.1715392E-31f;
byte[] b = ByteBuffer.allocate(4).putFloat(f).array();  //[12, 24, 19, 17]

Answer 2

从byte[] -> float，您可以这样做:

byte[] b = new byte[] { 12, 24, 19, 17};
float myfloatvalue = ByteBuffer.wrap(b).getFloat();

这里是使用ByteBuffer.allocate转换float -> byte[]的替代方法:

int bits = Float.floatToIntBits(myFloat);
byte[] bytes = new byte[4];
bytes[0] = (byte)(bits & 0xff);
bytes[1] = (byte)((bits >> 8) & 0xff);
bytes[2] = (byte)((bits >> 16) & 0xff);
bytes[3] = (byte)((bits >> 24) & 0xff);

Answer 3

将字节转换为整型并使用float . intbitstoffloat ()

http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Float.html intBitsToFloat (int)