在java中使String首字母大写

Question

As of now I'm using this code to make my first letter in a string capital

String output = input.substring(0, 1).toUpperCase() + input.substring(1);

This seems very dirty to me ..is there any direct or elegant way..

Answer 1

How about this:

String output = Character.toUpperCase(input.charAt(0)) + input.substring(1);

I can't think of anything cleaner without using external libraries, but this is definitely better than what you currently have.

Answer 2

You should have a look at StringUtils class from Apache Commons Lang lib - it has method .capitalize()

Description from the lib:

Capitalizes a String changing the first letter to title case as per Character.toTitleCase(char). No other letters are changed.

Answer 3

String out = Character.toUpperCase(inText.charAt(0)) + inText.substring(1).toLowerCase();

Answer 4

public static void main(String[] args) {
    String str = null;
    String outStr = null;
    Scanner sc = new Scanner(System.in);
    System.out.println("Enter a String: ");
    str = sc.nextLine();
    //c= Character.toUpperCase(str.charAt(0));

    for(int i=0; i< (str.length());i++){

        if(str.charAt(i)==' '){

            outStr= outStr.substring(0,i+1)+str.substring(i+1,i+2).toUpperCase()+str.substring(i+2);

        }else if(i==0){

            outStr=str.substring(0,1).toUpperCase()+str.substring(1);

        }
    }
    System.out.println("STRING::"+outStr);
}

Answer 5

Assuming you can use Java 8, here's the functional way that nobody asked for...

import java.util.Optional;
import java.util.stream.IntStream;

public class StringHelper {
    public static String capitalize(String source) {
        return Optional.ofNullable(source)
            .map(str -> IntStream.concat(
                str.codePoints().limit(1).map(Character::toUpperCase),
                str.codePoints().skip(1)))
            .map(stream -> stream.toArray())
            .map(arr -> new String(arr, 0, arr.length))
            .orElse(null);
    }
}

It's elegant in that it handles the null and empty string cases without any conditional statements.

Answer 6

Character.toString(a.charAt(0)).toUpperCase()+a.substring(1)

PS = a 是字符串。

Answer 7

Here, hold my beer

String foo = "suresh";
String bar = foo.toUpperCase();
if(bar.charAt[0] == 'S'){
   throw new SuccessException("bar contains 'SURESH' and has the first letter capital").
}

Answer 8

class strDemo3
{
    public static void main(String args[])
    {
        String s1=new String(" the ghost of the arabean sea");
        char c1[]=new char[30];       
        int c2[]=new int[30];
        s1.getChars(0,28,c1,0);
        for(int i=0;i<s1.length();i++)
        {
           System.out.print(c1[i]);
        }
        for(int i=1;i<s1.length();i++)
        {
           c2[i]=c1[i];
           if(c1[i-1]==' ')
           {
               c2[i]=c2[i]-32;
           }
           c1[i]=(char)c2[i];          
        }
        for(int i=0;i<s1.length();i++)
        {
           System.out.print(c1[i]);
        }            
       }
}