Java中byte数组和int类型的转换,在网络编程中这个算法是最基本的算法,我们都知道,在socket传输中,发送者接收的数据都是byte数组,但是int类型是4个byte组成的,如何把一个整形int转换成byte数组,同时如何把一个长度为4的byte数组转换成int类型。
方法一:
public static byte[] intToByteArray(int i) {
byte[] result = new byte[4];
// 由高位到低位
result[0] = (byte) ((i >> 24) & 0xFF);
result[1] = (byte) ((i >> 16) & 0xFF);
result[2] = (byte) ((i >> 8) & 0xFF);
result[3] = (byte) (i & 0xFF);
return result;
}
public static int byteArrayToInt(byte[] bytes) {
int value = 0;
// 由高位到低位
for (int i = 0; i < 4; i++) {
int shift = (4 - 1 - i) * 8;
value += (bytes[i] & 0x000000FF) << shift;// 往高位游
}
return value;
}
方法二:
此方法可以对string类型,float类型,char类型等 来与 byte类型的转换
public static void main(String[] args) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(baos);
try {
// int转换byte数组
dos.writeByte(-12);
dos.writeLong(12);
dos.writeChar('1');
dos.writeFloat(1.01f);
dos.writeUTF("好");
} catch (IOException e) {
e.printStackTrace();
} byte[] aa = baos.toByteArray();
ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
DataInputStream dis = new DataInputStream(bais);
// byte转换int
try {
System.out.println(dis.readByte());
System.out.println(dis.readLong());
System.out.println(dis.readChar());
System.out.println(dis.readFloat());
System.out.println(dis.readUTF());
} catch (IOException e) {
e.printStackTrace();
}
try {
dos.close();
dis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public class RandomUtil {
public static byte[] intToByteArray(int i) {
byte[] result = new byte[4];
// 由高位到低位
result[0] = (byte) ((i >> 24) & 0xFF);
result[1] = (byte) ((i >> 16) & 0xFF);
result[2] = (byte) ((i >> 8) & 0xFF);
result[3] = (byte) (i & 0xFF);
return result;
} public static void main(String[] args) {
int v = 123456;
byte[] bytes = ByteBuffer.allocate(4).putInt(v).array();
for (byte t : bytes) {
System.out.println(t);
}
System.out.println("----- 分割线 -------");
byte[] bytes2 = intToByteArray(v);
for (byte t : bytes2) {
System.out.println(t);
}
}
}