替换空格

 1 public class Problem05 {
 2     public static void main(String[] args) {
 3         //将字符串中的空格换为%20
 4         System.out.println(transform1("hello world"));
 5 
 6     }
 7     public static String transform(String string){
 8 
 9         return string.replace(" ","%20");
10     }
11 
12     public static String transform1(String string){
13         //以空格分割字符串
14         String ans="";
15 
16         String[] strings = string.split(" ");
17         for (int i = 0; i <= strings.length-2; i++) {
18             ans=strings[i]+"%20";
19         }
20         return ans+strings[strings.length-1];
21 
22 
23     }
24     public static String transform2(String string){
25         //遍历字符串
26         StringBuilder sb=new StringBuilder();
27 
28         for(int i=0;i<string.length();i++){
29             char c=string.charAt(i);
30 
31             if(c==‘ ‘) sb.append("%20");
32             else sb.append(c);
33         }
34         return sb.toString();
35     }
36 
37 }