Java基础类—Character

た入场券 2022-05-23 04:58 204阅读 0赞

Character类提供一些方法,比如:(小写字母、数字等)，并用于大小写转换。Character基于Unicode标准。

Java平台使用UTF-16表示Char、String、StringBUffer类。

[Unicode编码知识][Unicode]:

目前Unicode字符分为17组编排，从0X0000到0x10FFFF,每组有65536个码位，共1114112个码位。

基本多文种平面(第零平面)BMP范围：U+0000到U+FFFF，共65536个码位。

BMP中有一个专用区范围:0xE000到0xF8FF，共6400个码位。其中0xD800到0xDFFF，这2048个码位叫代理区。代理区的目的是用2个UTF-16字符表示BMP以外的字符，所以大于0x00FFFF的码位都需要使用代理区的码点。

代理区分为高位替代和低位替代，0xD800到0xDBFF为高位替代区，0xDC00到0xDFFF为低位替代区。

由于Unicode的最大码位为0x10FFFF,0xFFFF之前的（65536个码位）使用2个字节表示，0xFFFF之后（1048575(0xFFFFF)个码位）仅需要20位二进制就可以表示，因此规定多余的12位，高位字节前6位为：110110，低位字节前6位为:110111。

Character类将基本类型char包装在一个对象中

1、内部类、枚举

<table> 
 <tbody> 
 <tr> 
 <td>public&nbsp;static&nbsp;class&nbsp;Subset</td> 
 <td>Unicode字符集子类</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;final&nbsp;class&nbsp;UnicodeBlock&nbsp;extends&nbsp;Subset</td> 
 <td>根据Unicode硬编码范围划分</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;enum&nbsp;UnicodeScript</td> 
 <td>根据语言书写规则对Unicode字符划分</td> 
 </tr> 
 </tbody> 
</table>

2、常量

<table> 
 <tbody> 
 <tr> 
 <td>public static final int MIN_RADIX&nbsp;= 2;</td> 
 <td>最小基数</td> 
 </tr> 
 <tr> 
 <td>public static final int MAX_RADIX&nbsp;= 36;</td> 
 <td>最大基数</td> 
 </tr> 
 <tr> 
 <td>public static final char MIN_VALUE&nbsp;= '\u0000';</td> 
 <td>最小值</td> 
 </tr> 
 <tr> 
 <td>public static final char MAX_VALUE&nbsp;= '\uFFFF';</td> 
 <td>最大值</td> 
 </tr> 
 <tr> 
 <td>public static final byte UNASSIGNED&nbsp;= 0;</td> 
 <td>通用Unicode规范</td> 
 </tr> 
 <tr> 
 <td>......</td> 
 </tr> 
 <tr> 
 <td>public static final byte&nbsp;DIRECTIONALITY_POP_DIRECTIONAL_FORMAT&nbsp;= 18;</td> 
 </tr> 
 <tr> 
 <td>public static final char&nbsp;MIN_HIGH_SURROGATE&nbsp;= '\uD800';</td> 
 <td>高位代理区最小值</td> 
 </tr> 
 <tr> 
 <td>public static final char&nbsp;MAX_HIGH_SURROGATE&nbsp;= '\uDBFF';</td> 
 <td>高位代理区最大值</td> 
 </tr> 
 <tr> 
 <td>public static final char&nbsp;MIN_LOW_SURROGATE&nbsp;&nbsp;= '\uDC00';</td> 
 <td>低位代理区最小值</td> 
 </tr> 
 <tr> 
 <td>public static final char&nbsp;MAX_LOW_SURROGATE&nbsp;&nbsp;= '\uDFFF';</td> 
 <td>低位代理区最大值</td> 
 </tr> 
 <tr> 
 <td>public static final char&nbsp;MIN_SURROGATE&nbsp;= MIN_HIGH_SURROGATE;</td> 
 <td>代理区最小值</td> 
 </tr> 
 <tr> 
 <td>public static final char&nbsp;MAX_SURROGATE&nbsp;= MAX_LOW_SURROGATE;</td> 
 <td>代理区最大值</td> 
 </tr> 
 <tr> 
 <td>public static final int&nbsp;MIN_SUPPLEMENTARY_CODE_POINT&nbsp;= 0x010000;</td> 
 <td>补充码点最小值</td> 
 </tr> 
 <tr> 
 <td>public static final int&nbsp;MIN_CODE_POINT&nbsp;= 0x000000;</td> 
 <td>代码点最小值</td> 
 </tr> 
 <tr> 
 <td>public static final int&nbsp;MAX_CODE_POINT&nbsp;= 0X10FFFF;</td> 
 <td>代码点最大值</td> 
 </tr> 
 <tr> 
 <td>private final char value;</td> 
 <td>&nbsp;</td> 
 </tr> 
 </tbody> 
</table>

3.1、Subset类

<table> 
 <tbody> 
 <tr> 
 <td>public&nbsp;final&nbsp;boolean&nbsp;equals(Object obj)</td> 
 <td>&nbsp;</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;final&nbsp;int&nbsp;hashCode()</td> 
 <td>&nbsp;</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;final&nbsp;String toString()</td> 
 <td>&nbsp;</td> 
 </tr> 
 </tbody> 
</table>

3.2、UnicodeBlock类

<table> 
 <tbody> 
 <tr> 
 <td>private&nbsp;static&nbsp;Map&lt;String, UnicodeBlock&gt; map</td> 
 <td>缓存池</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;final&nbsp;UnicodeBlock &nbsp;BASIC_LATIN</td> 
 <td>Unicode字符块</td> 
 </tr> 
 <tr> 
 <td>......</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;final&nbsp;UnicodeBlock&nbsp;CJK_UNIFIED_IDEOGRAPHS_EXTENSION_D</td> 
 </tr> 
 <tr> 
 <td>private&nbsp;static&nbsp;final&nbsp;int&nbsp;blockStarts[]</td> 
 <td>Unicode字符集开始地址</td> 
 </tr> 
 <tr> 
 <td>private&nbsp;static&nbsp;final&nbsp;UnicodeBlock[] blocks</td> 
 <td>Unicode字符块数组</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;UnicodeBlock of(char&nbsp;c)</td> 
 <td>根据代码点查找Unicode字符块（折半查找）</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;UnicodeBlock of(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;final&nbsp;UnicodeBlock forName(String blockName)</td> 
 <td>从map缓存池中查找Unicode字符块</td> 
 </tr> 
 </tbody> 
</table>

3.3、UnicodeScript枚举

<table> 
 <tbody> 
 <tr> 
 <td>COMMON......UNKNOWN</td> 
 <td>枚举</td> 
 </tr> 
 <tr> 
 <td>private&nbsp;static&nbsp;final&nbsp;int[] scriptStarts</td> 
 <td>Unicode字符集开始地址</td> 
 </tr> 
 <tr> 
 <td>private&nbsp;static&nbsp;final&nbsp;UnicodeScript[] scripts</td> 
 <td>Unicode字符块数组</td> 
 </tr> 
 <tr> 
 <td>private&nbsp;static&nbsp;HashMap&lt;String,Character.UnicodeScript&gt; aliases</td> 
 <td>缓存池</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;UnicodeScript of(int&nbsp;codePoint) </td> 
 <td>根据代码点查找Unicode字符块（折半查找）</td> 
 </tr> 
 <tr> 
 <td>&nbsp;public&nbsp;static&nbsp;final&nbsp;UnicodeScript forName(String scriptName)</td> 
 <td>从aliases缓存池中查找Unicode字符块</td> 
 </tr> 
 </tbody> 
</table>

4、方法

<table> 
 <tbody> 
 <tr> 
 <td>private&nbsp;static&nbsp;class&nbsp;CharacterCache</td> 
 <td>将字符0-127放到缓存池中</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;Character valueOf(char&nbsp;c)</td> 
 <td>字符小于128则从缓存池中取，否则New一个对象</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;char&nbsp;charValue()</td> 
 <td>返回value</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;int&nbsp;hashCode()</td> 
 <td>&nbsp;</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;boolean&nbsp;equals(Object obj)</td> 
 <td>&nbsp;</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;String toString()</td> 
 <td>&nbsp;</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;String toString(char&nbsp;c)</td> 
 <td>&nbsp;</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isValidCodePoint(int&nbsp;codePoint)</td> 
 <td>是否为有效的代码点</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isBmpCodePoint(int&nbsp;codePoint)</td> 
 <td>是否为Bmp代码点</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;booleanisSupplementaryCodePoint(int&nbsp;codePoint)</td> 
 <td>是否为补充代码点</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isHighSurrogate(char&nbsp;ch)</td> 
 <td>是否为高位代理区</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isLowSurrogate(char&nbsp;ch)</td> 
 <td>是否为低位代理区</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isSurrogate(char&nbsp;ch)</td> 
 <td>是否为代理区</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isSurrogatePair(char&nbsp;high, char&nbsp;low)</td> 
 <td>是否为一个有效Unicode的代理对</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;charCount(int&nbsp;codePoint)</td> 
 <td>所需字符的数目（Bmp范围为1，否则为2）</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;toCodePoint(char&nbsp;high, char&nbsp;low)</td> 
 <td>代理对转换代码点</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;codePointAt(CharSequence seq, int&nbsp;index)</td> 
 <td>索引字符代码点</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;codePointAt(char[] a, int&nbsp;index)</td> 
 <td>索引字符代码点</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;codePointAt(char[] a, int&nbsp;index, int&nbsp;limit)</td> 
 </tr> 
 <tr> 
 <td>static&nbsp;int&nbsp;codePointAtImpl(char[] a, int&nbsp;index, int&nbsp;limit)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;codePointBefore(CharSequence seq, int&nbsp;index)</td> 
 <td>索引前一个字符的代码点</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;codePointBefore(char[] a, int&nbsp;index)</td> 
 <td>索引前一个字符的代码点</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;codePointBefore(char[] a, int&nbsp;index, int&nbsp;start)</td> 
 </tr> 
 <tr> 
 <td>static&nbsp;int&nbsp;codePointBeforeImpl(char[] a, int&nbsp;index, int&nbsp;start)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;char&nbsp;highSurrogate(int&nbsp;codePoint)</td> 
 <td>代码点返回高位代理</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;char&nbsp;lowSurrogate(int&nbsp;codePoint)</td> 
 <td>代码点返回低位代理</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;toChars(int&nbsp;codePoint, char[] dst, int&nbsp;dstIndex)</td> 
 <td>根据代码点返回字符</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;char[] toChars(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>static&nbsp;void&nbsp;toSurrogates(int&nbsp;codePoint, char[] dst, int&nbsp;index)</td> 
 <td>码点换成代理存到dst数组中</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;codePointCount(CharSequence seq, int&nbsp;beginIndex, int&nbsp;endIndex)</td> 
 <td>获取代码点总数</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;codePointCount(char[] a, int&nbsp;offset, int&nbsp;count)</td> 
 <td>获取代码点总数</td> 
 </tr> 
 <tr> 
 <td>static&nbsp;int&nbsp;codePointCountImpl(char[] a, int&nbsp;offset, int&nbsp;count)</td> 
 </tr> 
 <tr> 
 <td>&nbsp;public&nbsp;static&nbsp;int&nbsp;offsetByCodePoints(CharSequence seq, int&nbsp;index, int&nbsp;codePointOffset)</td> 
 <td>返回给定的字符子阵列是给定的索引由codePointOffset代码点偏移中的索引</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;offsetByCodePoints(char[] a, int&nbsp;start, int&nbsp;count,int&nbsp;index, int&nbsp;codePointOffset)</td> 
 <td>返回给定的字符子阵列是给定的索引由codePointOffset代码点偏移中的索引</td> 
 </tr> 
 <tr> 
 <td>static&nbsp;int&nbsp;offsetByCodePointsImpl(char[]a, int&nbsp;start, int&nbsp;count, int&nbsp;index&nbsp;int&nbsp;codePointOffset)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isLowerCase(char&nbsp;ch)</td> 
 <td>是否为小写字符</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isLowerCase(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isUpperCase(char&nbsp;ch)</td> 
 <td>是否为大写字符</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isUpperCase(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isTitleCase(char&nbsp;ch)</td> 
 <td>是否TitleCase字符</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isTitleCase(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isDigit(char&nbsp;ch)</td> 
 <td>是否为数字</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isDigit(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isDefined(char&nbsp;ch)</td> 
 <td>是否已定义</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isDefined(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isLetter(char&nbsp;ch)</td> 
 <td>是否为字母</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isLetter(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isLetterOrDigit(char&nbsp;ch)</td> 
 <td>是否为字母或数字</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isLetterOrDigit(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isAlphabetic(int&nbsp;codePoint)</td> 
 <td>&nbsp;</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isIdeographic(int&nbsp;codePoint)</td> 
 <td>&nbsp;</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isJavaIdentifierStart(char&nbsp;ch)</td> 
 <td>确定是否允许将指定字符作为 Java 标识符中的首字符</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isJavaIdentifierStart(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isJavaIdentifierPart(char&nbsp;ch)</td> 
 <td>确定字符（Unicode代码点）是否可以是 Java 标识符中首字符以外的部分。</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isJavaIdentifierPart(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isUnicodeIdentifierStart(char&nbsp;ch)</td> 
 <td>确定是否允许将指定字符作为 Unicode 标识符中的首字符</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isUnicodeIdentifierStart(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isUnicodeIdentifierPart(char&nbsp;ch)</td> 
 <td>确定指定字符是否可以是Unicode 标识符中首字符以外的部分</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isUnicodeIdentifierPart(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isIdentifierIgnorable(char&nbsp;ch)</td> 
 <td>确定是否应该认为指定字符是 Java 标识符或 Unicode 标识符中可忽略的一个字符</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isIdentifierIgnorable(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;char&nbsp;toLowerCase(char&nbsp;ch)</td> 
 <td>使用取自 UnicodeData 文件的大小写映射信息将字符参数转换为小写</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;toLowerCase(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;char&nbsp;toUpperCase(char&nbsp;ch)</td> 
 <td>使用取自UnicodeData 文件的大小写映射信息将字符参数转换为大写。</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;toUpperCase(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;char&nbsp;toTitleCase(char&nbsp;ch)</td> 
 <td>使用取自 UnicodeData 文件的大小写映射信息将字符参数转换为首字母大写</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;toTitleCase(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;digit(char&nbsp;ch, int&nbsp;radix)</td> 
 <td>返回使用指定基数的字符ch的数值</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;digit(int&nbsp;codePoint, int&nbsp;radix)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;getNumericValue(char&nbsp;ch)</td> 
 <td>返回指定的 Unicode 字符示的int值</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;getNumericValue(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isSpaceChar(char&nbsp;ch)</td> 
 <td>确定指定字符否Unicod空白字符</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isSpaceChar(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isWhitespace(char&nbsp;ch)</td> 
 <td>确定指定字符依据 Java 标准是否为空白字符</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isWhitespace(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isISOControl(char&nbsp;ch)</td> 
 <td>确定指定字符是否为 ISO 控制字符</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isISOControl(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;getType(char&nbsp;ch)</td> 
 <td>返回一个指示字符的常规类别的值</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;getType(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;char&nbsp;forDigit(int&nbsp;digit, int&nbsp;radix)</td> 
 <td>确定使用指定基数的特定数字的字符表示形式</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;byte&nbsp;getDirectionality(char&nbsp;ch)</td> 
 <td>返回给定字符的 Unicode 方向属性。利用字符方向性来计算文本的视觉顺序</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;byte&nbsp;getDirectionality(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isMirrored(char&nbsp;ch)</td> 
 <td>确定指定字符依据 Unicode 规范是否对称</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;boolean&nbsp;isMirrored(int&nbsp;codePoint)</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;int&nbsp;compareTo(Character anotherCharacter)</td> 
 <td>根据数字比较两个Character对象</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;int&nbsp;compare(char&nbsp;x, char&nbsp;y)</td> 
 <td>比较2个char的值</td> 
 </tr> 
 <tr> 
 <td>static&nbsp;int&nbsp;toUpperCaseEx(int&nbsp;codePoint)</td> 
 <td>转换成大写后返回</td> 
 </tr> 
 <tr> 
 <td>static&nbsp;char[] toUpperCaseCharArray(int&nbsp;codePoint)</td> 
 <td>返回大写字符数组</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;char&nbsp;reverseBytes(char&nbsp;ch)</td> 
 <td>返回通过反转指定char值中的字节顺序而获得的值</td> 
 </tr> 
 <tr> 
 <td>public&nbsp;static&nbsp;String getName(int&nbsp;codePoint)</td> 
 <td>返回指定名称</td> 
 </tr> 
 </tbody> 
</table>

CharacterCache方法将字符0-127放到缓存池中

private static class CharacterCache {
 private CharacterCache(){}
 
 static final Character cache[] = new Character[127 + 1];
 
 static {
 for (int i = 0; i < cache.length; i++)
 cache[i] = new Character((char)i);
 }
 }

在创建对象的时候可以通过valueOf来创建，如果是0-127内的字符，则直接通过缓存池直接返回。

public static Character valueOf(char c) {
 if (c <= 127) { // must cache
 return CharacterCache.cache[(int)c];
 }
 return new Character(c);
 }

[Unicode]: https://blog.csdn.net/wdeng2011/article/details/80155795