Java type conversion instance

Java type conversion instance

For example, convert the string content to a floating point number and then restore the original string content.

Import java. io. unsupportedEncodingException; import java. nio. byteBuffer; import java. nio. doubleBuffer; import java. nio. floatBuffer; public class test3 {public static void main (String [] args) {new test3 ();}/*** first Method * // *** 1, integer to byte array conversion ** @ param number * @ return */public static byte [] intToByte (int number) {int temp = number; byte [] B = new byte [4]; for (int I = B. length-1; I>-1; I --) {B [I] = new Integer (temp & 0xff ). byteValue (); // Save the highest bit in the temperature bit temp = temp> 8; // shift to the right eight places} return B;}/*** 2, convert byte arrays to Integers ** @ param B * @ return */public static int byteToInt (byte [] B) {int s = 0; for (int I = 0; I <3; I ++) {if (B [I]> = 0) s = s + B [I]; elses = s + 256 + B [I]; s = s * 256;} if (B [3]> = 0) // The last one is not multiplied because s = s + B [3] may overflow. elses = s + 256 + B [3]; return s ;}/ *** 3, character to byte conversion ** @ param ch * @ return */public static byte [] charToByte (char ch) {int temp = (int) ch; byte [] B = new byte [2]; for (int I = B. length-1; I>-1; I --) {B [I] = new Integer (temp & 0xff ). byteValue (); // Save the highest bit in the temperature bit temp = temp> 8; // shift to the right eight places} return B;}/*** 4, byte to character conversion ** @ param B * @ return */public static char byteToChar (byte [] B) {int s = 0; if (B [0]> 0) s + = B [0]; elses + = 256 + B [0]; s * = 256; if (B [1]> 0) s + = B [1]; elses + = 256 + B [1]; char ch = (char) s; return ch;}/*** 5, double-precision floating point to byte conversion ** @ param d * @ return */public static byte [] doubleToByte (double d) {byte [] B = new byte [8]; long l = Double. doubleToLongBits (d); for (int I = 0; I <B. length; I ++) {B [I] = new Long (l ). byteValue (); l = l> 8;} return B;}/*** 6, byte to double Precision Floating Point conversion ** @ param B * @ return */public static double byteToDouble (byte [] B) {long l; l = B [0]; l & = 0xff; l | = (long) B [1] <8); l & = 0 xffff; l | = (long) B [2] <16); l & = 0 xffffff; l | = (long) B [3] <24); l & = 0 xffffffffl; l | = (long) B [4] <32); l & = 0 xffffffffl; l | = (long) B [5] <40 ); l & = 0 xffffffffffl; l | = (long) B [6] <48); l | = (long) B [7] <56 ); return Double. longBitsToDouble (l);}/*** 7, single-precision floating point conversion to byte ** @ param f * @ return */public static byte [] float2byte (float f) {// convert float to byte [] int fbit = Float. floatToIntBits (f); byte [] B = new byte [4]; for (int I = 0; I <4; I ++) {B [I] = (byte) (fbit> (24-I * 8);} // flip the array int len = B. length; // create an array byte [] dest = new byte [len] That is the same as the source array element type; // to prevent modification to the source array, copy a copy of the source array System. arraycopy (B, 0, dest, 0, len); byte temp; // switch the order I and the reciprocal I for (int I = 0; I <len/2; ++ I) {temp = dest [I]; dest [I] = dest [len-I-1]; dest [len-I-1] = temp;} return dest;}/***, 8, convert byte to single precision Floating Point ** @ param B * byte (at least 4 bytes) * @ param index * start position * @ return */public static float byte2float (byte [] B, int index) {int l; l = B [index + 0]; l & = 0xff; l | = (long) B [index + 1] <8 ); l & = 0 xffff; l | = (long) B [index + 2] <16); l & = 0 xffffff; l | = (long) B [index + 3] <24); return Float. intBitsToFloat (l );} /*** convert Byte to String or convert String to Byte *** @ author Administrator *** // *** default character set encoding UTF-8 one Chinese Character occupies three bytes */ private static String CHAR_ENCODE = UTF-8; /*** set the global character encoding ** @ param charEncode */public static void configCharEncode (String charEncode) {CHAR_ENCODE = charEncode ;} /*** @ param str * The Source String converted into a byte array * @ return */public static byte [] StringToByte (String str) {return StringToByte (str, CHAR_ENCODE);}/***** @ param srcObj * convert the Source byte array to a String byte array * @ return */public static String ByteToString (byte [] srcObj) {return ByteToString (srcObj, CHAR_ENCODE );} /*** UTF-8 a Chinese character occupies three bytes ** @ param str * Source String converted into a byte array String * @ return */public static byte [] StringToByte (String str, string charEncode) {byte [] destObj = null; try {if (null = str | str. trim (). equals () {destObj = new byte [0]; return destObj;} else {destObj = str. getBytes (charEncode) ;}} catch (UnsupportedEncodingException e) {e. printStackTrace ();} return destObj ;} /*** @ param srcObj * convert the Source byte array to a String byte array * @ return */public static String ByteToString (byte [] srcObj, String charEncode) {String destObj = null; try {destObj = new String (srcObj, charEncode);} catch (UnsupportedEncodingException e) {e. printStackTrace ();} return destObj. replaceAll (,);}/*** Convert byte [] to hex string ** @ param src * @ return */public static String bytesToHexString (byte [] src) {StringBuilder stringBuilder = new StringBuilder (); if (src = null | src. length <= 0) {return null;} for (int I = 0; I <src. length; I ++) {int v = src [I] & 0xFF; String hv = Integer. toHexString (v); if (hv. length () <2) {stringBuilder. append (0);} stringBuilder. append (hv);} return stringBuilder. toString ();}/*** Convert hex string to byte [] ** @ param hexString * @ return */public static byte [] hexStringToBytes (String hexString) {if (hexString = null | hexString. equals () {return null;} hexString = hexString. toUpperCase (); int length = hexString. length ()/2; char [] hexChars = hexString. toCharArray (); byte [] d = new byte [length]; for (int I = 0; I <length; I ++) {int pos = I * 2; d [I] = (byte) (charToBytes (hexChars [pos]) <4 | charToBytes (hexChars [pos + 1]);} return d ;} /*** Convert char to byte ** @ param c * @ return */private static byte charToBytes (char c) {return (byte) 0123456789ABCDEF. indexOf (c);}/*** method 2 * // *** 1, BYTE to INT ** @ param B * @ return */protected int byteArrayToInt (byte [] B) {return (B [0] <24) + (B [1] & 0xFF) <16) + (B [2] & 0xFF) <8) + (B [3] & 0xFF );} /***, 2, BYTE to SHORT ** @ param B * @ return */protected int byteArrayToShort (byte [] B) {return (B [0] <8) + (B [1] & 0xFF);}/***, 3, SHORT to BYTE data ** @ param s * @ return */protected byte [] Using tobytearray (short s) {byte [] Using Buf = new byte [2]; for (int I = 0; I <2; I ++) {int offset = (partial Buf. length-1-I) * 8; your Buf [I] = (byte) (s >>> offset) & 0xff);} return your Buf ;}/***, 4. Convert INT data to BYTE data ** @ param I * @ return */protected byte [] intToByteArray (int I) {byte [] result = new byte [4]; 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 ;} /***, 5, convert the long type to a byte array ** @ param bb * @ param x * @ param index */public byte [] longToByteArray (long x, int index) {byte [] bb = new byte [8]; bb [index + 7] = (byte) (x> 56); bb [index + 6] = (byte) (x> 48); bb [index + 5] = (byte) (x> 40); bb [index + 4] = (byte) (x> 32); bb [index + 3] = (byte) (x> 24); bb [index + 2] = (byte) (x> 16); bb [index + 1] = (byte) (x> 8); bb [index + 0] = (byte) (x> 0); return bb;}/***, 6, get long ** @ param bb * @ param index * @ return */public long byteArrayToLong (byte [] bb, int index) {return (long) bb [index + 7] & 0xff) <56) | (long) bb [index + 6] & 0xff) <48) | (long) bb [index + 5] & 0xff) <40) | (long) bb [index + 4] & 0xff) <32) | (long) bb [index + 3] & 0xff) <24) | (long) bb [index + 2] & 0xff) <16) | (long) bb [index + 1] & 0xff) <8) | (long) bb [index + 0] & 0xff) <0 ));}/***, 7. float conversion byte ** @ param bb * @ param x * @ param index */public static byte [] floatTobyteArray (float v) {ByteBuffer bb = ByteBuffer. allocate (4); byte [] ret = new byte [4]; FloatBuffer fb = bb. asFloatBuffer (); fb. put (v); bb. get (ret); return ret;}/***, 8, float ** @ param bb * @ param index * @ return */public static float byteArrayToFloat (byte [] v) {ByteBuffer bb = ByteBuffer. wrap (v); FloatBuffer fb = bb. asFloatBuffer (); return fb. get ();}/***, 9, double conversion byte ** @ param bb * @ param x * @ param index */public byte [] doubleToByteArray (double x) {ByteBuffer bb = ByteBuffer. allocate (8); byte [] ret = new byte [8]; DoubleBuffer fb = bb. asDoubleBuffer (); fb. put (x); bb. get (ret); return ret;}/***, 10, float ** @ param bb * @ param index * @ return */public double byteArrayToDouble (byte [] B) {ByteBuffer bb = ByteBuffer. wrap (B); DoubleBuffer fb = bb. asDoubleBuffer (); return fb. get ();} public test3 () {// example: Convert the String Content to a floating point number, and then restore the original String Content = Contiune; System. out. println (for example, convert the string content to a floating point number, and then restore the original string content); // 1, convert the string to a floating point // (1) first convert the string to an array System. out. println (1, string to floating point: (1) first convert string to array Content = + StringToByte (Content); // (2) then convert array to floating point System. out. println (1, the string is converted to a floating point: (1) then the array is converted to a floating point Content = + byteToDouble (StringToByte (Content); // 2, the floating point is converted to a string // (1) first, convert the floating point to the byte array System. out. println (2, floating point to string :( 1) convert floating point to byte array Content = + doubleToByte (byteToDouble (StringToByte (Content); // (2) then convert the byte array to the string System. out. println (2, floating point to string :( 2) convert byte array to string Content = + ByteToString (doubleToByte (byteToDouble (StringToByte (Content )))));}}

The output is as follows:

For example, convert the string content to a floating point number and then restore the original string content.
1. Convert string to floating point: (1) convert string to array Content = [B @ 659e0bfd
1. Convert string to floating point: (1) convert array to floating point Content = 3.949643824749462E180
2. Convert floating point to string: (1) first convert floating point to byte array Content = [B @ 2a139a55
2. convert a floating point to a string: (2) convert the byte array to the string Content = Contiune to restore the original string Content.