1、Java标示符

2、常量与变量

3、Java数据类型

4、基本数据类型

基本数据类型(8种）整数类型（byte 、short、int、long）浮点数类型(float、double) 布尔类型(boolean) 字符类型(char)

public class TestTypes {
    public static void main(String[] args) {
        byte b = 123;
        short s = 1000;
        int i =1;
        long l1  = 1L;
        long l2 = 1l;
        int i8 = 012;
        int i16 = 0x12;
        float f1 = 10.0f;
        float f2 = 10.0F;
        double d1 = 12.3;
        double d2 = 1.2e3;
        char c1 = 0x48;
        char c2 = 'H';
        System.out.println(b);
        System.out.println(s);
        System.out.println(i);
        System.out.println(l1);
        System.out.println(l2);
        System.out.println(i8);
        System.out.println(i16);
        System.out.println(f1);
        System.out.println(f2);
        System.out.println(d1);
        System.out.println(d2);
        System.out.println(c1);
        System.out.println(c2);
    }
}

输出，