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