Java : Charset 示例

Charset (Java SE 22 & JDK 22) 示例。
您将在大多数 Charset 方法中找到代码示例。

注解 :

本文可能使用了翻译软件以方便阅读。另请查看英文原文。

简介

16 位 Unicode 代码单元序列与字节序列之间的命名映射。此类定义用于创建解码器和编码器以及用于检索与字符集相关联的各种名称的方法。此类的实例是不可变的。 (机器翻译)

Class diagram

final var utf8 = StandardCharsets.UTF_8;
System.out.println(utf8); // UTF-8

final var sjis = Charset.forName("Shift_JIS");
System.out.println(sjis); // Shift_JIS

final var text = "abc♪";
System.out.println(text); // abc♪

final var encodedUtf8 = text.getBytes(utf8);
System.out.println(Arrays.toString(encodedUtf8)); // [97, 98, 99, -30, -103, -86]

final var encodedSjis = text.getBytes(sjis);
System.out.println(Arrays.toString(encodedSjis)); // [97, 98, 99, -127, -12]

final var charset = Charset.defaultCharset();
System.out.println(charset); // UTF-8

Constructors

Charset (String canonicalName, String[] aliases)

使用给定的规范名称和别名集初始化一个新的字符集。 (机器翻译)

protected. I think it's rare to create a subclass of this class. Therefore, the code example is omitted.

Methods

final Set<String> aliases ()

返回包含此字符集别名的集合。 (机器翻译)

final var charset = StandardCharsets.UTF_8;
System.out.println(charset); // UTF-8
System.out.println(charset.aliases()); // [unicode-1-1-utf-8, UTF8]

static SortedMap<String,Charset> availableCharsets ()

构造从规范字符集名称到字符集对象的排序映射。 (机器翻译)

final var charsets = Charset.availableCharsets();
for (final var charset : charsets.values()) {
    System.out.println(charset);
}

// Result
// ↓
//Big5
//Big5-HKSCS
//CESU-8
//EUC-JP
//EUC-KR
//GB18030
//GB2312
//GBK
//...
//Shift_JIS
//...
//UTF-16
//UTF-16BE
//UTF-16LE
//UTF-32
//UTF-32BE
//UTF-32LE
//UTF-8
//...

boolean canEncode ()

告诉该字符集是否支持编码。 (机器翻译)

final var charset = StandardCharsets.UTF_8;
System.out.println(charset); // UTF-8
System.out.println(charset.canEncode()); // true

final var encoded = charset.encode("abc♪");
System.out.println(encoded); // java.nio.HeapByteBuffer[pos=0 lim=6 cap=9]

final var array = encoded.array();
System.out.println(Arrays.toString(array)); // [97, 98, 99, -30, -103, -86, 0, 0, 0]

final int compareTo (Charset that)

将此字符集与另一个字符集进行比较。 (机器翻译)

final var charset1 = StandardCharsets.UTF_8;
final var charset2 = StandardCharsets.ISO_8859_1;
final var charset3 = StandardCharsets.US_ASCII;

System.out.println(charset1.compareTo(charset1)); // 0
System.out.println(charset1.compareTo(charset2)); // 12
System.out.println(charset1.compareTo(charset3)); // 1

System.out.println(charset2.compareTo(charset3)); // -12

abstract boolean contains (Charset cs)

判断该字符集是否包含给定的字符集。 (机器翻译)

final var utf8 = StandardCharsets.UTF_8;
final var ascii = StandardCharsets.US_ASCII;

System.out.println(utf8.contains(ascii)); // true
System.out.println(ascii.contains(utf8)); // false

final CharBuffer decode (ByteBuffer bb)

将此字符集中的字节解码为 Unicode 字符的便捷方法。 (机器翻译)

final var charset = StandardCharsets.UTF_8;
System.out.println(charset); // UTF-8

final var encoded = charset.encode("abc♪");
System.out.println(encoded); // java.nio.HeapByteBuffer[pos=0 lim=6 cap=9]

final var array = encoded.array();
System.out.println(Arrays.toString(array)); // [97, 98, 99, -30, -103, -86, 0, 0, 0]

final var decoded = charset.decode(encoded);
System.out.println(decoded); // abc♪

static Charset defaultCharset ()

返回此 Java 虚拟机的默认字符集。 (机器翻译)

final var charset = Charset.defaultCharset();
System.out.println(charset); // UTF-8

String displayName ()

返回此字符集的默认语言环境的人类可读名称。 (机器翻译)

final var utf8 = StandardCharsets.UTF_8;
System.out.println(utf8.displayName()); // UTF-8

final var ascii = StandardCharsets.US_ASCII;
System.out.println(ascii.displayName()); // US-ASCII

String displayName (Locale locale)

返回此字符集在给定语言环境中的人类可读名称。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var charset = StandardCharsets.UTF_8;
System.out.println(charset.displayName()); // UTF-8
System.out.println(charset.displayName(Locale.JAPAN)); // UTF-8

final ByteBuffer encode (String str)

使用此字符集将字符串编码为字节的便捷方法。 (机器翻译)

final var charset = StandardCharsets.UTF_8;
System.out.println(charset); // UTF-8

final var encoded = charset.encode("abc♪");
System.out.println(encoded); // java.nio.HeapByteBuffer[pos=0 lim=6 cap=9]

final var array = encoded.array();
System.out.println(Arrays.toString(array)); // [97, 98, 99, -30, -103, -86, 0, 0, 0]

final var decoded = charset.decode(encoded);
System.out.println(decoded); // abc♪

final ByteBuffer encode (CharBuffer cb)

将 Unicode 字符编码为此字符集中的字节的便捷方法。 (机器翻译)

final var charset = StandardCharsets.UTF_8;
System.out.println(charset); // UTF-8

final var cb = CharBuffer.wrap("abc♪");

final var encoded = charset.encode(cb);
System.out.println(encoded); // java.nio.HeapByteBuffer[pos=0 lim=6 cap=9]

final var array = encoded.array();
System.out.println(Arrays.toString(array)); // [97, 98, 99, -30, -103, -86, 0, 0, 0]

final var decoded = charset.decode(encoded);
System.out.println(decoded); // abc♪

final boolean equals (Object ob)

判断该对象是否等于另一个对象。 (机器翻译)

final var charset1 = StandardCharsets.UTF_8;
final var charset2 = StandardCharsets.US_ASCII;

System.out.println(charset1.equals(charset1)); // true
System.out.println(charset1.equals(charset2)); // false

static Charset forName (String charsetName)

返回指定字符集的字符集对象。 (机器翻译)

final var utf8 = Charset.forName("UTF-8");
System.out.println(utf8); // UTF-8
System.out.println(utf8.equals(StandardCharsets.UTF_8)); // true

final var sjis = Charset.forName("Shift_JIS");
System.out.println(sjis); // Shift_JIS

static Charset forName (String charsetName, Charset fallback)

返回指定字符集的字符集对象。 (机器翻译)

final var charset = Charset.forName("UTF-8", StandardCharsets.US_ASCII);
System.out.println(charset); // UTF-8

final var charset = Charset.forName("xxx", StandardCharsets.US_ASCII);
System.out.println(charset); // US-ASCII

final int hashCode ()

返回此字符集的哈希码。 (机器翻译)

final var charset = StandardCharsets.UTF_8;
System.out.println(charset.hashCode()); // 81070450

final var charset = StandardCharsets.UTF_16;
System.out.println(charset.hashCode()); // -1781783509

final var charset = StandardCharsets.US_ASCII;
System.out.println(charset.hashCode()); // -185735358

final boolean isRegistered ()

告知此字符集是否已在 IANA 字符集注册表中注册。 (机器翻译)

final var charset = StandardCharsets.UTF_8;
System.out.println(charset); // UTF-8
System.out.println(charset.isRegistered()); // true

final var charset = Charset.forName("x-windows-50220");
System.out.println(charset); // x-windows-50220
System.out.println(charset.isRegistered()); // false

static boolean isSupported (String charsetName)

告知是否支持指定的字符集。 (机器翻译)

System.out.println(Charset.isSupported("UTF-8")); // true
System.out.println(Charset.isSupported("US-ASCII")); // true
System.out.println(Charset.isSupported("Shift_JIS")); // true

System.out.println(Charset.isSupported("xxx")); // false

final String name ()

返回此字符集的规范名称。 (机器翻译)

final var charset = StandardCharsets.UTF_8;
System.out.println(charset.name()); // UTF-8

final var charset = StandardCharsets.US_ASCII;
System.out.println(charset.name()); // US-ASCII

final var charset = Charset.forName("Shift_JIS");
System.out.println(charset.name()); // Shift_JIS

abstract CharsetDecoder newDecoder ()

为该字符集构造一个新的解码器。 (机器翻译)

final var charset = StandardCharsets.UTF_8;
System.out.println(charset); // UTF-8

final var encoder = charset.newEncoder();
final var decoder = charset.newDecoder();

final var cb = CharBuffer.wrap("abc♪");

final var encoded = encoder.encode(cb);
System.out.println(encoded); // java.nio.HeapByteBuffer[pos=0 lim=6 cap=9]

final var array = encoded.array();
System.out.println(Arrays.toString(array)); // [97, 98, 99, -30, -103, -86, 0, 0, 0]

final var decoded = decoder.decode(encoded);
System.out.println(decoded); // abc♪

abstract CharsetEncoder newEncoder ()

为该字符集构造一个新的编码器。 (机器翻译)

final var charset = StandardCharsets.UTF_8;
System.out.println(charset); // UTF-8

final var encoder = charset.newEncoder();
final var decoder = charset.newDecoder();

final var cb = CharBuffer.wrap("abc♪");

final var encoded = encoder.encode(cb);
System.out.println(encoded); // java.nio.HeapByteBuffer[pos=0 lim=6 cap=9]

final var array = encoded.array();
System.out.println(Arrays.toString(array)); // [97, 98, 99, -30, -103, -86, 0, 0, 0]

final var decoded = decoder.decode(encoded);
System.out.println(decoded); // abc♪

final String toString ()

返回描述此字符集的字符串。 (机器翻译)

final var charset = StandardCharsets.UTF_8;
final var ret = charset.toString();
System.out.println(ret); // UTF-8

final var charset = StandardCharsets.US_ASCII;
final var ret = charset.toString();
System.out.println(ret); // US-ASCII

final var charset = Charset.forName("Shift_JIS");
final var ret = charset.toString();
System.out.println(ret); // Shift_JIS

API 示例

Java : Charset 示例

简介

Constructors

Charset (String canonicalName, String[] aliases)

Methods

final Set<String> aliases ()

static SortedMap<String,Charset> availableCharsets ()

boolean canEncode ()

final int compareTo (Charset that)

abstract boolean contains (Charset cs)

final CharBuffer decode (ByteBuffer bb)

static Charset defaultCharset ()

String displayName ()

String displayName (Locale locale)

final ByteBuffer encode (String str)

final ByteBuffer encode (CharBuffer cb)

final boolean equals (Object ob)

static Charset forName (String charsetName)

static Charset forName (String charsetName, Charset fallback)

final int hashCode ()

final boolean isRegistered ()

static boolean isSupported (String charsetName)

final String name ()

abstract CharsetDecoder newDecoder ()

abstract CharsetEncoder newEncoder ()

final String toString ()

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