byte b =127;//范围-128至127                short s = 2;                int j = 123;                long l = 1234L;//后面标记L确定为long型                int c = (int)1234l;//强制转换，显示转换                long ll = b;                float f = 123.45f;//需要在数字末尾加“f”标记                double d =12345;                f = (float)d;//强制转换，必须是相关数据类型才可以转换                f = l;                char v ='a';//单引号‘’引起来你的单个字符                int a = v;                System.out.println("a =" +a);                char g = 98;                System.out.println("g =" +g);//ASCII码                //UTF-8                boolean t = true;     //逻辑真，true和false都是小写                t = false;//逻辑假