Java中byte、byte数组与int、long的转换详解
一、Java中byte和int之间的转换源码:
//byte与int的相互转换 publicstaticbyteintToByte(intx){ return(byte)x; } publicstaticintbyteToInt(byteb){ //Java总是把byte当做有符处理;我们可以通过将其和0xFF进行二进制与得到它的无符值 returnb&0xFF; }
测试代码:
//测试int转byte intint0=234; bytebyte0=intToByte(int0); System.out.println("byte0="+byte0);//byte0=-22 //测试byte转int intint1=byteToInt(byte0); System.out.println("int1="+int1);//int1=234
二、Java中byte数组和int之间的转换源码:
//byte数组与int的相互转换 publicstaticintbyteArrayToInt(byte[]b){ returnb[3]&0xFF| (b[2]&0xFF)<<8| (b[1]&0xFF)<<16| (b[0]&0xFF)<<24; } publicstaticbyte[]intToByteArray(inta){ returnnewbyte[]{ (byte)((a>>24)&0xFF), (byte)((a>>16)&0xFF), (byte)((a>>8)&0xFF), (byte)(a&0xFF) }; }
测试代码:
//测试int转byte数组 intint2=1417; byte[]bytesInt=intToByteArray(int2); System.out.println("bytesInt="+bytesInt);//bytesInt=[B@de6ced //测试byte数组转int intint3=byteArrayToInt(bytesInt); System.out.println("int3="+int3);//int3=1417
三、Java中byte数组和long之间的转换源码:
privatestaticByteBufferbuffer=ByteBuffer.allocate(8); //byte数组与long的相互转换 publicstaticbyte[]longToBytes(longx){ buffer.putLong(0,x); returnbuffer.array(); } publicstaticlongbytesToLong(byte[]bytes){ buffer.put(bytes,0,bytes.length); buffer.flip();//needflip returnbuffer.getLong(); }
测试代码:
//测试long转byte数组 longlong1=2223; byte[]bytesLong=longToBytes(long1); System.out.println("bytes="+bytesLong);//bytes=[B@c17164 //测试byte数组转long longlong2=bytesToLong(bytesLong); System.out.println("long2="+long2);//long2=2223
四、整体工具类源码:
importjava.nio.ByteBuffer; publicclassTest{ privatestaticByteBufferbuffer=ByteBuffer.allocate(8); publicstaticvoidmain(String[]args){ //测试int转byte intint0=234; bytebyte0=intToByte(int0); System.out.println("byte0="+byte0);//byte0=-22 //测试byte转int intint1=byteToInt(byte0); System.out.println("int1="+int1);//int1=234 //测试int转byte数组 intint2=1417; byte[]bytesInt=intToByteArray(int2); System.out.println("bytesInt="+bytesInt);//bytesInt=[B@de6ced //测试byte数组转int intint3=byteArrayToInt(bytesInt); System.out.println("int3="+int3);//int3=1417 //测试long转byte数组 longlong1=2223; byte[]bytesLong=longToBytes(long1); System.out.println("bytes="+bytesLong);//bytes=[B@c17164 //测试byte数组转long longlong2=bytesToLong(bytesLong); System.out.println("long2="+long2);//long2=2223 } //byte与int的相互转换 publicstaticbyteintToByte(intx){ return(byte)x; } publicstaticintbyteToInt(byteb){ //Java总是把byte当做有符处理;我们可以通过将其和0xFF进行二进制与得到它的无符值 returnb&0xFF; } //byte数组与int的相互转换 publicstaticintbyteArrayToInt(byte[]b){ returnb[3]&0xFF| (b[2]&0xFF)<<8| (b[1]&0xFF)<<16| (b[0]&0xFF)<<24; } publicstaticbyte[]intToByteArray(inta){ returnnewbyte[]{ (byte)((a>>24)&0xFF), (byte)((a>>16)&0xFF), (byte)((a>>8)&0xFF), (byte)(a&0xFF) }; } //byte数组与long的相互转换 publicstaticbyte[]longToBytes(longx){ buffer.putLong(0,x); returnbuffer.array(); } publicstaticlongbytesToLong(byte[]bytes){ buffer.put(bytes,0,bytes.length); buffer.flip();//needflip returnbuffer.getLong(); } }
运行测试结果:
byte0=-22 int1=234 bytesInt=[B@de6ced int3=1417 bytes=[B@c17164 long2=2223
总结
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