Java中的 Charset availableCharsets() 方法及示例

availableCharsets()方法是Java的内置方法 .nio.charset构造从规范字符集名称到字符集对象的排序映射。这样返回的地图将为每个字符集都有一个条目。如果有多个同名的条目，它只存储其中一个，这完全依赖于Java虚拟机。在程序的每次执行中，如果新的字符集提供程序动态地可供当前Java虚拟机使用，则输出可能会有所不同。

语法：

public static SortedMap availableCharsets()

参数：该函数不接受任何参数。

返回值：该函数返回一个不可变的、不区分大小写的映射。它来自命名为字符集对象的规范字符集。

下面是上述函数的实现：

方案一：

// Java program to demonstrate
// the above function
  
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.Map;
  
public class GFG {
  
    public static void main(String[] args)
    {
        // Creates a map of charsets
        Map charsets
            = Charset.availableCharsets();
  
        // Iterator to store the type
        Iterator iterator
            = charsets.values().iterator();
  
        // Iterate till we get all the charsets
        while (iterator.hasNext()) {
  
            // Get the next
            Charset all = (Charset)iterator.next();
  
            // Displays the name
            System.out.print(all.displayName() + " ");
        }
    }
}

输出：

Big5 Big5-HKSCS CESU-8 EUC-JP EUC-KR GB18030 GB2312 GBK IBM-Thai IBM00858 IBM01140 IBM01141 IBM01142 IBM01143 IBM01144 IBM01145 IBM01146 IBM01147 IBM01148 IBM01149 IBM037 IBM1026 IBM1047 IBM273 IBM277 IBM278 IBM280 IBM284 IBM285 IBM290 IBM297 IBM420 IBM424 IBM437 IBM500 IBM775 IBM850 IBM852 IBM855 IBM857 IBM860 IBM861 IBM862 IBM863 IBM864 IBM865 IBM866 IBM868 IBM869 IBM870 IBM871 IBM918 ISO-2022-CN ISO-2022-JP ISO-2022-JP-2 ISO-2022-KR ISO-8859-1 ISO-8859-13 ISO-8859-15 ISO-8859-2 ISO-8859-3 ISO-8859-4 ISO-8859-5 ISO-8859-6 ISO-8859-7 ISO-8859-8 ISO-8859-9 JIS_X0201 JIS_X0212-1990 KOI8-R KOI8-U Shift_JIS TIS-620 US-ASCII UTF-16 UTF-16BE UTF-16LE UTF-32 UTF-32BE UTF-32LE UTF-8 windows-1250 windows-1251 windows-1252 windows-1253 windows-1254 windows-1255 windows-1256 windows-1257 windows-1258 windows-31j x-Big5-HKSCS-2001 x-Big5-Solaris x-COMPOUND_TEXT x-euc-jp-linux x-EUC-TW x-eucJP-Open x-IBM1006 x-IBM1025 x-IBM1046 x-IBM1097 x-IBM1098 x-IBM1112 x-IBM1122 x-IBM1123 x-IBM1124 x-IBM1166 x-IBM1364 x-IBM1381 x-IBM1383 x-IBM300 x-IBM33722 x-IBM737 x-IBM833 x-IBM834 x-IBM856 x-IBM874 x-IBM875 x-IBM921 x-IBM922 x-IBM930 x-IBM933 x-IBM935 x-IBM937 x-IBM939 x-IBM942 x-IBM942C x-IBM943 x-IBM943C x-IBM948 x-IBM949 x-IBM949C x-IBM950 x-IBM964 x-IBM970 x-ISCII91 x-ISO-2022-CN-CNS x-ISO-2022-CN-GB x-iso-8859-11 x-JIS0208 x-JISAutoDetect x-Johab x-MacArabic x-MacCentralEurope x-MacCroatian x-MacCyrillic x-MacDingbat x-MacGreek x-MacHebrew x-MacIceland x-MacRoman x-MacRomania x-MacSymbol x-MacThai x-MacTurkish x-MacUkraine x-MS932_0213 x-MS950-HKSCS x-MS950-HKSCS-XP x-mswin-936 x-PCK x-SJIS_0213 x-UTF-16LE-BOM X-UTF-32BE-BOM X-UTF-32LE-BOM x-windows-50220 x-windows-50221 x-windows-874 x-windows-949 x-windows-950 x-windows-iso2022jp

参考： https://docs.oracle.com/javase/9/docs/api/ Java/nio/charset/Charset.html#availableCharsets–