本文转自：http://blog.csdn.net/eddle/article/details/6892271
一、JAVA进制类型转换
十进制转成十六进制：
Integer.toHexString(int i)
十进制转成八进制
Integer.toOctalString(int i)
十进制转成二进制
Integer.toBinaryString(int i)
十六进制转成十进制
Integer.valueOf("FFFF",16).toString()
八进制转成十进制
Integer.valueOf("876",8).toString()
二进制转十进制
Integer.valueOf("0101",2).toString()
有什么方法可以直接将2,8,16进制直接转换为10进制的吗?
java.lang.Integer类
parseInt(String s, int radix)
使用第二个参数指定的基数，将字符串参数解析为有符号的整数。
examples from jdk:
parseInt("0", 10) returns 0
parseInt("473", 10) returns 473
parseInt("-0", 10) returns 0
parseInt("-FF", 16) returns -255
parseInt("1100110", 2) returns 102
parseInt("2147483647", 10) returns 2147483647
parseInt("-2147483648", 10) returns -2147483648
parseInt("2147483648", 10) throws a NumberFormatException
parseInt("99", 8) throws a NumberFormatException
parseInt("Kona", 10) throws a NumberFormatException
parseInt("Kona", 27) returns 411787
进制转换如何写（二，八，十六）不用算法
Integer.toBinaryString
Integer.toOctalString
Integer.toHexString
二、字节数组与JAVA类型转换
//long类型转成byte数组
public static byte[] longToByte(long number) {
long temp = number;
byte[] b = new byte[8];
for (int i = 0; i < b.length; i++) {
b[i] = new Long(temp & 0xff).byteValue();//
将最低位保存在最低位
temp = temp >> 8; // 向右移8位
}
return b;
}
//byte数组转成long
public static long byteToLong(byte[] b) {
long s = 0;
long s0 = b[0] & 0xff;// 最低位
long s1 = b[1] & 0xff;
long s2 = b[2] & 0xff;
long s3 = b[3] & 0xff;
long s4 = b[4] & 0xff;// 最低位
long s5 = b[5] & 0xff;
long s6 = b[6] & 0xff;
long s7 = b[7] & 0xff;
// s0不变
s1 <<= 8;
s2 <<= 16;
s3 <<= 24;
s4 <<= 8 * 4;
s5 <<= 8 * 5;
s6 <<= 8 * 6;
s7 <<= 8 * 7;
s = s0 | s1 | s2 | s3 | s4 | s5 | s6 | s7;
return s;
}
/**
* 注释：int到字节数组的转换！
*
* @param number
* @return
*/
public static byte[] intToByte(int number) {
int temp = number;
byte[] b = new byte[4];
for (int i = 0; i < b.length; i++) {
b[i] = new Integer(temp & 0xff).byteValue();//
将最低位保存在最低位
temp = temp >> 8; // 向右移8位
}
return b;
}
/**
* 注释：字节数组到int的转换！
*
* @param b
* @return
*/
public static int byteToInt(byte[] b) {
int s = 0;
int s0 = b[0] & 0xff;// 最低位
int s1 = b[1] & 0xff;
int s2 = b[2] & 0xff;
int s3 = b[3] & 0xff;
s3 <<= 24;
s2 <<= 16;
s1 <<= 8;
s = s0 | s1 | s2 | s3;
return s;
}
/**
* 注释：short到字节数组的转换！
*
* @param s
* @return
*/
public static byte[] shortToByte(short number) {
int temp = number;
byte[] b = new byte[2];
for (int i = 0; i < b.length; i++) {
b[i] = new Integer(temp & 0xff).byteValue();//
将最低位保存在最低位
temp = temp >> 8; // 向右移8位
}
return b;
}
/**
* 注释：字节数组到short的转换！
*
* @param b
* @return
*/
public static short byteToShort(byte[] b) {
short s = 0;
short s0 = (short) (b[0] & 0xff);// 最低位
short s1 = (short) (b[1] & 0xff);
s1 <<= 8;
s = (short) (s0 | s1);
return s;
}