除了处理外，Short和Character有什么区别? [英] What is the difference between Short and Character apart from processing?

问题描述

据我所知

• 按字节"，看起来好像一样(它们都长2个字节)；
但是，
• Character 对其有更多处理(静态 .isLetter()方法及其他，等等).

• "bytewise", it looks like they are the same (they are both 2 bytes long);
• Character, however, has more processing to it (static .isLetter() method and others, etc).

虽然我的问题听起来有些愚蠢，但它们是:

While my questions may sound dumb, here they are:

• 除非我的第一个假设是错误的，为什么为什么会有原始类型 char 和 short ，因为它们具有相同的内部长度"，并且总之就没有未签名的原始类型Java中的类型?
• Short 是 final ，如果不是， Character 是否可以扩展 Short ?

• unless my first assumption is wrong, why are there primitive types char and short since they have the same "internal length` and, anyway, there are no unsigned primitive types in Java?
• Short is final, if it weren't, could Character have extended Short?

编辑:给出了答案，但我错了:Java中有 个未签名的原始类型，即... char .

EDIT: answer given and I was wrong: there is one unsigned primitive type in Java and that is... char.

编辑2 :@PatriciaShanahan还提到，在算术操作中， char 的行为类似于无符号的16位整数，就像>短.并且这包括左移，即符号位 随身携带，就像 short 一样.

EDIT 2: @PatriciaShanahan also mentions that in arithmetic operations, a char behaves like an unsigned 16bit integer, just like a short. And this includes left shifts, that is, the sign bit is carried along, just like for short.

推荐答案

本质区别是 short 是带符号的， char 是未签名的.

The essential difference is that short is signed, char is unsigned.

public class CharVsShort {
  public static void main(String[] args) throws Exception {
    short ffShort = (short)0xFFFF;
    char ffChar = (char)0xFFFF;

    System.out.println("all-1s-short = " + (int)ffShort);
    System.out.println("all-1s-char  = " + (int)ffChar);
  }
}

打印

all-1s-short = -1
all-1s-char  = 65535

Java语言规范第4.2节指出

整数类型为 byte ， short ， int 和 long ，其值均为8位，分别为16位，32位和64位带符号的两个补码整数和 char ，其值为16位 unsigned >代表UTF-16代码单位的整数

The integral types are byte, short, int, and long, whose values are 8-bit, 16-bit, 32-bit and 64-bit signed two's-complement integers, respectively, and char, whose values are 16-bit unsigned integers representing UTF-16 code units

(我的粗体).还将类型的范围明确指定为

(my bold). It also gives the types' ranges explicitly as

• byte ，从-128到127，包括
• short ，从-32768到32767，包括
• int ，从-2147483648到2147483647(含)
• long ，从-9223372036854775808到9223372036854775807，包括
• char ，从'\ u0000'到'\ uffff'(包括0到65535)

• byte, from -128 to 127, inclusive
• short, from -32768 to 32767, inclusive
• int, from -2147483648 to 2147483647, inclusive
• long, from -9223372036854775808 to 9223372036854775807, inclusive
• char, from '\u0000' to '\uffff' inclusive, that is, from 0 to 65535

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