java - 如何检查字符串是否可以某种编码方式编码？

Question

以下测试在转换后的 Latin1 上失败，因为非法字符被替换为值为 63(问号)的字节。问题是这些字符应该更好地导致一些异常......

  @Test
  public void testEncoding() throws UnsupportedEncodingException {
    final String czech = "Řízeček a šampáňo a žízeň";
    // okay
    final byte[] bytesInLatin2 = czech.getBytes("ISO8859-2");
    // different bytes, but okay
    final byte[] bytesInWin1250 = czech.getBytes("Windows-1250");
    // different bytes, but okay
    final byte[] bytesInUtf8 = czech.getBytes("UTF-8");
    // nonsense; Ř,č,... are not in Latin1 code set!!!
    final byte[] bytesInLatin1 = czech.getBytes("ISO8859-1");

    System.out.println(Arrays.toString(bytesInLatin2));
    System.out.println(Arrays.toString(bytesInWin1250));
    System.out.println(Arrays.toString(bytesInUtf8));
    System.out.println(Arrays.toString(bytesInLatin1));
    System.out.flush();

    final String latin2 = new String(bytesInLatin2, "ISO8859-2");
    final String win1250 = new String(bytesInWin1250, "Windows-1250");
    final String utf8 = new String(bytesInUtf8, "UTF-8");
    final String latin1 = new String(bytesInLatin1, "ISO8859-1");

    Assert.assertEquals("latin2", czech, latin2);
    Assert.assertEquals("win1250", czech, win1250);
    Assert.assertEquals("utf8", czech, utf8);
    Assert.assertEquals("latin1", czech, latin1); // this test will fail!
  }

在很多情况下，由于 Java 的这种行为，数据最终会被破坏。如果字符串可通过某种编码进行编码，是否有任何库可用于验证字符串？

Answer 1

我怀疑您正在寻找 CharsetEncoder.canEncode(CharSequence) .

Charset latin2 = Charset.forName("ISO8859-2");
boolean validInLatin2 = latin2.newEncoder().canEncode(czech);
...