Java基本数据类型

数据类型	最小值	最大值	占用字节	占用bits	默认值	可否作为Switch条件
byte	-128	127	1	8	0	可以
boolean			1	8	false	不可以
short	-32768	32767	2	16	0	可以
char		?	2	16		可以
int	-2147483648	2147483647	4	32	0	可以
float	1.4E-45	3.4028235E+38	4	32	0.0	不可以
double	4.9E-324	1.7976931348623157E308	8	64	0.0	不可以
long	-9223372036854770000	9223372036854770000	8	64	0	不可以

①1字节=8bits  ②String类型也可以用作Switch条件  ③String的默认值为null

测试代码：

package com.click369;

public class NumberTest {

    static byte b;
    static short s;
    static int i;
    static double d;
    static float f;
    static char c;
    static long l;
    static boolean bool;
    static String str;

    public static void main(String[] args) {
        // Java中除了boolean类型之外的7种基本数据类型：
        System.out.println("Java 8种基本数据类型所占位数、最小值、最大值：");
        System.out.println("byte size: " + Byte.SIZE);
        System.out.println("byte min: " + Byte.MIN_VALUE);
        System.out.println("byte max: " + Byte.MAX_VALUE);
        
        System.out.println("char size: " + Character.SIZE);
        System.out.println("char min: " + Character.MIN_VALUE);
        System.out.println("char max: " + Character.MAX_VALUE);

        System.out.println("short size: " + Short.SIZE);
        System.out.println("short min: " + Short.MIN_VALUE);
        System.out.println("short max: " + Short.MAX_VALUE);

        System.out.println("int size: " + Integer.SIZE);
        System.out.println("int min: " + Integer.MIN_VALUE);
        System.out.println("int max: " + Integer.MAX_VALUE);

        System.out.println("float size: " + Float.SIZE);
        System.out.println("float min: " + Float.MIN_VALUE);
        System.out.println("float max: " + Float.MAX_VALUE);
        
        System.out.println("double size: " + Double.SIZE);
        System.out.println("double min: " + Double.MIN_VALUE);
        System.out.println("double max: " + Double.MAX_VALUE);

        System.out.println("long size: " + Long.SIZE);
        System.out.println("long min: " + Long.MIN_VALUE);
        System.out.println("long max: " + Long.MAX_VALUE);

        // 输出默认值
        System.out.println("str = " + str);
        System.out.println("b = " + b);
        System.out.println("s = " + s);
        System.out.println("i = " + i);
        System.out.println("d = " + d);
        System.out.println("f = " + f);
        System.out.println("c = " + c);
        System.out.println("l = " + l);
        System.out.println("bool = " + bool);
    }

}