java 如何将十六进制字符串转换为 float 符点型?
先上代码:
- package com.weixiao.network;
- /**
- * java 如何将十六进制字符串转换为 float 符点型?相互转换
- * Hex2Float
- * @author 微wx笑
- * @date 2017年12月6日下午5:22:10
- */
- public class Hex2Float {
- public static void main(String[] args) {
- String hexString = "46105cec";
- Long l = Hex2Float.parseLong(hexString, 16);
- Float f = Float.intBitsToFloat(l.intValue());
- System.out.println(hexString);
- System.out.println(l);
- System.out.println(f);
- System.out.println(Integer.toHexString(Float.floatToIntBits(f)));
- Integer i = Integer.parseInt(hexString, 16);
- f = Float.intBitsToFloat(i.intValue());
- System.out.println("");
- System.out.println(i);
- System.out.println(f);
- System.out.println(Integer.toHexString(Float.floatToIntBits(f)));
- hexString = "-c6105cec";
- l = Hex2Float.parseLong(hexString, 16);
- f = Float.intBitsToFloat(l.intValue());
- System.out.println("");
- System.out.println(hexString);
- System.out.println(l);
- System.out.println(f);
- System.out.println(Integer.toHexString(Float.floatToIntBits(f))); // 使用 Long 会输出:ffffffffc6105cec
- i = Integer.parseInt(hexString, 16); // 使用 Integer 会抛异常: java.lang.NumberFormatException: For input string: "c6105cec"
- f = Float.intBitsToFloat(i.intValue());
- System.out.println("");
- System.out.println(i);
- System.out.println(f);
- System.out.println(Integer.toHexString(Float.floatToIntBits(f)));
- }
- /**
- * 代码来自:java.lang.Long
- * 因为要跟踪看变量的值,所以要copy出来,或者是去附加源码,否则 eclipse 调试时查看变量的值会提示 xxx cannot be resolved to a variable
- * @author 微wx笑
- * @date 2017年12月6日下午5:19:40
- * @param s
- * @param radix
- * @return
- * @throws NumberFormatException
- */
- public static long parseLong(String s, int radix) throws NumberFormatException {
- if (s == null) {
- throw new NumberFormatException("null");
- }
- if (radix < Character.MIN_RADIX) {
- throw new NumberFormatException("radix " + radix + " less than Character.MIN_RADIX");
- }
- if (radix > Character.MAX_RADIX) {
- throw new NumberFormatException("radix " + radix + " greater than Character.MAX_RADIX");
- }
- long result = 0;
- boolean negative = false;
- int i = 0,
- len = s.length();
- long limit = -Long.MAX_VALUE;
- long multmin;
- int digit;
- if (len > 0) {
- char firstChar = s.charAt(0);
- if (firstChar < '0') { // Possible leading "+" or "-"
- if (firstChar == '-') {
- negative = true;
- limit = Long.MIN_VALUE;
- } else if (firstChar != '+') throw NumberFormatException.forInputString(s);
- if (len == 1) // Cannot have lone "+" or "-"
- throw NumberFormatException.forInputString(s);
- i++;
- }
- multmin = limit / radix;
- while (i < len) {
- // Accumulating negatively avoids surprises near MAX_VALUE
- digit = Character.digit(s.charAt(i++), radix);
- if (digit < 0) {
- throw NumberFormatException.forInputString(s);
- }
- if (result < multmin) {
- throw NumberFormatException.forInputString(s);
- }
- result *= radix;
- if (result < limit + digit) {
- throw NumberFormatException.forInputString(s);
- }
- result -= digit;
- }
- } else {
- throw NumberFormatException.forInputString(s);
- }
- return negative ? result: -result;
- }
- }
- /**
- * 代码来自:java.lang.NumberFormatException
- * NumberFormatException
- * @author 微wx笑
- * @date 2017年12月6日下午5:20:36
- */
- class NumberFormatException extends IllegalArgumentException {
- /**
- *
- */
- private static final long serialVersionUID = 1L;
- public NumberFormatException(String s) {
- super(s);
- }
- static NumberFormatException forInputString(String s) {
- return new NumberFormatException("For input string: \"" + s + "\"");
- }
- }
对应的输出如下:
- 46105cec
- 1175477484
- 9239.23
- 46105cec
- 1175477484
- 9239.23
- 46105cec
- -c6105cec
- -3322961132
- 4.5707135E-4
- 39efa314
- Exception in thread "main" java.lang.NumberFormatException: For input string: "-c6105cec"
- at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
- at java.lang.Integer.parseInt(Integer.java:583)
- at com.weixiao.network.Hex2Float.main(Hex2Float.java:36)
对,你没看错,上面的代码有会抛出异常的!
Why?
你注意到将十六进制字符串转换为 float,和将 float 转换为十六进制字符串 的区别了吗?
前面是用 Long,后面是用 Integer,为什么不用相同的类型呢?
后面的异常就是解释这个的。
来源: http://blog.csdn.net/testcs_dn/article/details/78731698