java 位操作 bitwise(按位) operation bit

操作longValue = longValue | (1 << n); 可以在longValue的2进制表示中，把从右边数到左边数第n + 1位的值设置为1，并且不影响其他位上面的值   即用0和2进制值变量x做或|or操作，不会影响到2进制变量x的值

操作longValue = longValue & ~(1 << n); 可以在longValue的2进制表示中，把从右边数到左边数第n + 1位设置为0，并且不影响其他位上面的值   即用1和2进制值变量x做与&and操作，不会影响到2进制变量x的值

操作System.out.println((longValue >> n & 1) == 1); 可以判断值longValue的2进制表示中，从右边数到左边第n + 1位的值是0false 还是1true

public class bitOperation {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		long longValue = 0;
		
		longValue = longValue | (1 << 0);
		// 1
		System.out.println(Long.toBinaryString(longValue));
		longValue = longValue | (1 << 1);
		// 11
		System.out.println(Long.toBinaryString(longValue));
		longValue = longValue | (1 << 4);
		// 10011
		System.out.println(Long.toBinaryString(longValue));
		longValue = longValue | (1 << 5);
		// 110011
		System.out.println(Long.toBinaryString(longValue));
		longValue = longValue | (1 << 6);
		// 1110011
		System.out.println(Long.toBinaryString(longValue));

		String hex = Long.toBinaryString(longValue);
		// 1110011
		System.out.println(hex);
		// 115
		System.out.println(Integer.valueOf("1110011", 2));
		// 1110011
		System.out.println(Long.toBinaryString(longValue >> 0));
		// 1
		System.out.println(Long.toBinaryString(longValue >> 0 & 1));
		// 111001
		System.out.println(Long.toBinaryString(longValue >> 1));
		// 1
		System.out.println(Long.toBinaryString(longValue >> 1 & 1));
		// true
		System.out.println((longValue >> 0 & 1) == 1);
		// true
		System.out.println((longValue >> 1 & 1) == 1);
		// false
		System.out.println((longValue >> 2 & 1) == 1);
		// false
		System.out.println((longValue >> 3 & 1) == 1);
		// true
		System.out.println((longValue >> 4 & 1) == 1);
		// true
		System.out.println((longValue >> 5 & 1) == 1);
		// true
		System.out.println((longValue >> 6 & 1) == 1);
		// false
		System.out.println((longValue >> 7 & 1) == 1);

		// Demonstrate the bitwise logical operators.
		bitLogic();
		// Left shifting a byte value.
		byteShift();
	}

	/**
	 * Left shifting a byte value.
	 */
	private static void byteShift() {
		byte a = 64, b;
		int i;

		i = a << 2;
		b = (byte) (a << 2);

		// Original value of a: 64
		System.out.println("Original value of a: " + a);
		// i and b: 256 0
		System.out.println("i and b: " + i + " " + b);
		System.out.println("\r\n");
	}

	/**
	 * Demonstrate the bitwise logical operators.
	 */
	private static void bitLogic() {
		String binary[] = { "0000", "0001", "0010", "0011", "0100", "0101",
				"0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101",
				"1110", "1111"

		};
		int a = 3; // 0 + 2 + 1 or 0011 in binary
		int b = 6; // 4 + 2 + 0 or 0110 in binary
		int c = a | b;
		int d = a & b;
		int e = a ^ b;
		int f = (~a & b) | (a & ~b);
		int g = ~a & 0x0f;

		// a = 0011 = 3
		System.out.println(" a = " + binary[a] + " = " + a);
		// b = 0110 = 6
		System.out.println(" b = " + binary[b] + " = " + b);
		// a|b = 0111 = 7
		System.out.println(" a|b = " + binary[c] + " = " + c);
		// a&b = 0010 = 2
		System.out.println(" a&b = " + binary[d] + " = " + d);
		// a^b = 0101 = 5
		System.out.println(" a^b = " + binary[e] + " = " + e);
		// ~a&b|a&~b = 0101 = 5
		System.out.println("~a&b|a&~b = " + binary[f] + " = " + f);
		// ~a = 1100 = 12
		System.out.println(" ~a = " + binary[g] + " = " + g);
		System.out.println("\r\n");
	}
}