String Capitalize - meilleur moyen

Regardez cette question conversion de titlecase . Apache FTW.

Si je devais écrire une bibliothèque, j'essaierais de m'assurer que j'ai eu mon droit d'unicode de beofre vous inquiétant de la performance. Sur le dessus de ma tête:

int len = str.length();
if (len == 0) {
    return str;
}
int head = Character.toUpperCase(str.codePointAt(0));
String tail = str.substring(str.offsetByCodePoints(0, 1));
return new String(new int[] { head }).concat(tail);

Utilisez cette méthode pour capitaliser de la chaîne. sa fonctionne totalement sans bug xxx

/**
     * capitalize the first letter of a string
     * 
     * @param String
     * @return String
     * */
    public static String capitalizeFirst(String s) {
        if (s == null || s.length() == 0) {
            return "";
        }
        char first = s.charAt(0);
        if (Character.isUpperCase(first)) {
            return s;
        } else {
            return Character.toUpperCase(first) + s.substring(1);
        }
    }

Si vous ne capitalisez que des mots limités, vous feriez mieux de le mettre en cache.

@Test
public void testCase()
{
    String all = "At its base, a shell is simply a macro processor that executes commands. The term macro processor means functionality where text and symbols are expanded to create larger expressions.\n" +
            "\n" +
            "A Unix shell is both a command interpreter and a programming language. As a command interpreter, the shell provides the user interface to the rich set of GNU utilities. The programming language features allow these utilities to be combined. Files containing commands can be created, and become commands themselves. These new commands have the same status as system commands in directories such as /bin, allowing users or groups to establish custom environments to automate their common tasks.\n" +
            "\n" +
            "Shells may be used interactively or non-interactively. In interactive mode, they accept input typed from the keyboard. When executing non-interactively, shells execute commands read from a file.\n" +
            "\n" +
            "A shell allows execution of GNU commands, both synchronously and asynchronously. The shell waits for synchronous commands to complete before accepting more input; asynchronous commands continue to execute in parallel with the shell while it reads and executes additional commands. The redirection constructs permit fine-grained control of the input and output of those commands. Moreover, the shell allows control over the contents of commands’ environments.\n" +
            "\n" +
            "Shells also provide a small set of built-in commands (builtins) implementing functionality impossible or inconvenient to obtain via separate utilities. For example, cd, break, continue, and exec cannot be implemented outside of the shell because they directly manipulate the shell itself. The history, getopts, kill, or pwd builtins, among others, could be implemented in separate utilities, but they are more convenient to use as builtin commands. All of the shell builtins are described in subsequent sections.\n" +
            "\n" +
            "While executing commands is essential, most of the power (and complexity) of shells is due to their embedded programming languages. Like any high-level language, the shell provides variables, flow control constructs, quoting, and functions.\n" +
            "\n" +
            "Shells offer features geared specifically for interactive use rather than to augment the programming language. These interactive features include job control, command line editing, command history and aliases. Each of these features is described in this manual.";
    String[] split = all.split("[\\W]");

    // 10000000
    // upper Used 606
    // hash Used 114

    // 100000000
    // upper Used 5765
    // hash Used 1101

    HashMap<String, String> cache = Maps.newHashMap();

    long start = System.currentTimeMillis();
    for (int i = 0; i < 100000000; i++)
    {

        String upper = split[i % split.length].toUpperCase();

//            String s = split[i % split.length];
//            String upper = cache.get(s);
//            if (upper == null)
//            {
//                cache.put(s, upper = s.toUpperCase());
// 
//            }
    }
    System.out.println("Used " + (System.currentTimeMillis() - start));
}