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

String str = "java";
String cap = str.substring(0, 1).toUpperCase() + str.substring(1);
// cap = "Java"

用你的例子:

public static void main(String[] args) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    // Actually use the Reader
    String name = br.readLine();
    // Don't mistake String object with a Character object
    String s1 = name.substring(0, 1).toUpperCase();
    String nameCapitalized = s1 + name.substring(1);
    System.out.println(nameCapitalized);
}

其他回答

试试这个

这个方法做的是,考虑单词“hello world”这个方法把它变成“hello world”每个单词的开头大写。

 private String capitalizer(String word){

        String[] words = word.split(" ");
        StringBuilder sb = new StringBuilder();
        if (words[0].length() > 0) {
            sb.append(Character.toUpperCase(words[0].charAt(0)) + words[0].subSequence(1, words[0].length()).toString().toLowerCase());
            for (int i = 1; i < words.length; i++) {
                sb.append(" ");
                sb.append(Character.toUpperCase(words[i].charAt(0)) + words[i].subSequence(1, words[i].length()).toString().toLowerCase());
            }
        }
        return  sb.toString();

    }

谢谢,我已经阅读了一些评论,并带来了以下内容

public static void main(String args[]) 
{
String myName = "nasser";
String newName = myName.toUpperCase().charAt(0) +  myName.substring(1);
System.out.println(newName );
}

我希望它能有所帮助 祝你好运

您可以使用以下代码:

public static String capitalizeString(String string) {

    if (string == null || string.trim().isEmpty()) {
        return string;
    }
    char c[] = string.trim().toLowerCase().toCharArray();
    c[0] = Character.toUpperCase(c[0]);

    return new String(c);

}

使用JUnit的示例测试:

@Test
public void capitalizeStringUpperCaseTest() {

    String string = "HELLO WORLD  ";

    string = capitalizeString(string);

    assertThat(string, is("Hello world"));
}

@Test
public void capitalizeStringLowerCaseTest() {

    String string = "hello world  ";

    string = capitalizeString(string);

    assertThat(string, is("Hello world"));
}
import java.util.*;
public class Program
{
    public static void main(String[] args) 
      {
        Scanner sc=new Scanner(System.in);
        String s1=sc.nextLine();
        String[] s2=s1.split(" ");//***split text into words***
        ArrayList<String> l = new ArrayList<String>();//***list***
        for(String w: s2)
        l.add(w.substring(0,1).toUpperCase()+w.substring(1)); 
        //***converting 1st letter to capital and adding to list***
        StringBuilder sb = new StringBuilder();//***i used StringBuilder to convert words to text*** 
        for (String s : l)
          {
             sb.append(s);
             sb.append(" ");
          }
      System.out.println(sb.toString());//***to print output***
      }
}

我已经使用split函数将字符串分割成单词,然后我再次使用list来获得该单词的第一个字母大写,然后我使用字符串生成器以字符串格式打印输出,其中包含空格

试试这个,对我很管用。

public static String capitalizeName(String name) {
    String fullName = "";
    String names[] = name.split(" ");
    for (String n: names) {
        fullName = fullName + n.substring(0, 1).toUpperCase() + n.toLowerCase().substring(1, n.length()) + " ";
    }
    return fullName;
}