我使用Java从用户获得一个字符串输入。我试着让输入的第一个字母大写。

我试了一下:

String name;

BufferedReader br = new InputStreamReader(System.in);

String s1 = name.charAt(0).toUppercase());

System.out.println(s1 + name.substring(1));

这导致了以下编译错误:

类型不匹配:不能从InputStreamReader转换为BufferedReader 不能在基本类型char上调用toUppercase()


当前回答

你可以试试这个

/**
 * capitilizeFirst(null)  -> ""
 * capitilizeFirst("")    -> ""
 * capitilizeFirst("   ") -> ""
 * capitilizeFirst(" df") -> "Df"
 * capitilizeFirst("AS")  -> "As"
 *
 * @param str input string
 * @return String with the first letter capitalized
 */
public String capitilizeFirst(String str)
{
    // assumptions that input parameter is not null is legal, as we use this function in map chain
    Function<String, String> capFirst = (String s) -> {
        String result = ""; // <-- accumulator

        try { result += s.substring(0, 1).toUpperCase(); }
        catch (Throwable e) {}
        try { result += s.substring(1).toLowerCase(); }
        catch (Throwable e) {}

        return result;
    };

    return Optional.ofNullable(str)
            .map(String::trim)
            .map(capFirst)
            .orElse("");
}

其他回答

public static String capitalizer(final String texto) {

    // split words
    String[] palavras = texto.split(" ");
    StringBuilder sb = new StringBuilder();

    // list of word exceptions
    List<String> excessoes = new ArrayList<String>(Arrays.asList("de", "da", "das", "do", "dos", "na", "nas", "no", "nos", "a", "e", "o", "em", "com"));

    for (String palavra : palavras) {

        if (excessoes.contains(palavra.toLowerCase()))
            sb.append(palavra.toLowerCase()).append(" ");
        else
            sb.append(Character.toUpperCase(palavra.charAt(0))).append(palavra.substring(1).toLowerCase()).append(" ");
    }
    return sb.toString().trim();
}

用WordUtils capitalize (str)。

你可以使用类WordUtils。

假设你的字符串是“当前地址”,然后使用

* * * *强烈textWordutils.capitaliz(字符串); 输出:当前地址

参见:http://commons.apache.org/proper/commons-lang/apidocs/org/apache/commons/lang3/text/WordUtils.html

来自Apache Commons的wordutil .capitalize(java.lang.String)。

给出的答案是只大写一个单词的第一个字母。使用以下代码将整个字符串大写。

public static void main(String[] args) {
    String str = "this is a random string";
    StringBuilder capitalizedString = new StringBuilder();
    String[] splited = str.trim().split("\\s+");

    for (String string : splited) {         
        String s1 = string.substring(0, 1).toUpperCase();
        String nameCapitalized = s1 + string.substring(1);

        capitalizedString.append(nameCapitalized);
        capitalizedString.append(" ");
    }
    System.out.println(capitalizedString.toString().trim());
}

输出: 这是一个随机字符串