java实现——004替换空格

1.创建新的字符串

public class T004 {
    public static void main(String[] args){
        System.out.println(replaceBlank("we are happy"));
    }
    public static String replaceBlank(String s){
        String r = "%20";
        String result = "";
        for(int i=0;i<s.length();i++){
            if(s.charAt(i)==' '){
                result +=r;
            }else{
                result += s.charAt(i);
            }
        }
        return result;
        
    }
}

2.在原来的字符串上做替换