java_String类练习

 1 public class StringTest {
 2     //1.模拟trim方法，去除字符串两端的空格
 3     public static void main(String[] args) {
 4         String str = "  ai  kang        ";
 5         char c = str.charAt(0);
 6        while (true){
 7            if(str.startsWith(" ")){
 8                str = str.substring(1);
 9            }else if(str.endsWith(" ")){
10                str = str.substring(0,str.length()-1);
11            }else{
12                break;
13            }
14        }
15         System.out.println(str);
16     }
17 }

 1 public class StringTest01 {
 2     //2.将一个字符串进行反转，将字符串中指定部分进行反转，比如"abcdefg"反转
 3     public static void main(String[] args) {
 4         String str = "abcdefg";
 5         char[] c = str.toCharArray();
 6         for (int i = 0; i < str.length()/2; i++) {
 7             char c1 = c[c.length-i-1];
 8             c[c.length-i-1] = c[i];
 9             c[i] = c1;
10         }
11         String str1 = new String(c);
12         System.out.println(str1);
13     }
14 }