long a1 = 12;String s1 = a1 + "";                  // 法1：直接加空串System.out.println(s1);long a2 = 34;String s2 = String.valueOf(a2);      // 法2：String.valueOf()System.out.println(s2);long a3 = 56;String s3 = Long.toString(a3);       // 法3：Long.toString()System.out.println(s3);

转载：https://blog.csdn.net/kzadmxz/article/details/80600145