java中如何将byte数组内容转换为字符串？

public class bytetest {
 public static void main(string[] args) {
 string str = "hello world!";
 // string转byte
 byte[] bs = str.getbytes();
 system.out.println(arrays.tostring(bs));

 // byte转string
 string str2 = new string(bs);
 system.out.println(str2);
 }
}