在Java中自动生成一个字符串

根据您的用例,将省略号放在字母之间可能很有用(即在末尾添加字母以提供一些上下文):

/**
 * Puts ellipses in input strings that are longer than than maxCharacters. Shorter strings or
 * null is returned unchanged.
 * @param input the input string that may be subjected to shortening
 * @param maxCharacters the maximum characters that are acceptable for the unshortended string. Must be at least 3, otherwise a string with ellipses is too long already.
 * @param charactersAfterEllipsis the number of characters that should appear after the ellipsis (0 or larger) 
 * @return the truncated string with trailing ellipses
 */
public static String ellipsize(String input, int maxCharacters, int charactersAfterEllipsis) {
  if(maxCharacters < 3) {
    throw new IllegalArgumentException("maxCharacters must be at least 3 because the ellipsis already take up 3 characters");
  }
  if(maxCharacters - 3 > charactersAfterEllipsis) {
    throw new IllegalArgumentException("charactersAfterEllipsis must be less than maxCharacters");
  }
  if (input == null || input.length() < maxCharacters) {
    return input;
  }
  return input.substring(0, maxCharacters - 3 - charactersAfterEllipsis) + "..." + input.substring(input.length() - charactersAfterEllipsis);
}

还有一些更复杂的特性,您可能需要省略号算法:如果您需要将文本放置到图形元素中,并且使用的是比例字体,那么您必须测量字符串的长度。

对于秋千/秋千 java.awt.Font.getStringBounds . 在这种情况下,一个简单的算法会一次剪切字符串一个字母并添加省略号,直到字符串符合给定的限制。如果经常使用,在 http://www.codeproject.com/KB/cs/AutoEllipsis.aspx?msg=3278640 (C,但应该足够容易翻译成Java)可以节省一些处理器周期。

此方法将返回椭圆化字符串:

String ellipsize(String input, int maxLength) {
    String ellip = "...";
    if (input == null || input.length() <= maxLength 
           || input.length() < ellip.length()) {
        return input;
    }
    return input.substring(0, maxLength - ellip.length()).concat(ellip);
}

一个单一的解决方案,当然不会超过其他提供的解决方案:

longString.replaceFirst("(.{5}).+(.{5})", "$1...$2")

只留下前5个字符,然后放…在中间。

没有。但这是一个简单方法的另一个突破。

String ellipsize(String input, int maxLength) {
  if (input == null || input.length() < maxLength) {
    return input;
  }
  return input.substring(0, maxLength) + "...";
}

当然,试试这个:

public static String ellipsise (String input, int maxLen) {
    if (input == null)
        return null;
    if ((input.length() < maxLen) || (maxLen < 3))
        return input;
    return input.substring (0, maxLen - 3) + "...";
}

这样做的好处是修复了国王英语使用不当的错误:—)