LeetCode——Number of 1 Bits

//求一个整数的二进制串中1的个数

public int hammingWeight(int n) {
	    String b_str = Integer.toBinaryString(n);
	    int b_count = 0;
	    for(int i=0; i<b_str.length(); i++) {
	        if(b_str.charAt(i) == '1') {
	            b_count ++;
	        }
	    }
	    return b_count;
}