byte String 转换

public class ChangeVar {

	public static void main(String[] args) {
		String str = "123456789abcdefg";
		byte[] b = str.getBytes();
		
		//wrong
		String str_a = b.toString();
		System.out.println(str_a);
		
		//right
		String str_b = new String(b);
		System.out.println(str_b);
		
	}

}