將一個字符串進行反轉。將字符串中指定部分進行反轉。

 

package com.yhqtv.java;

/*
 * 將一個字符串進行反轉。將字符串中指定部分進行反轉。比如“abcdef”反轉為“abfedcg”
 * @author  XMKJ  yhqtv.com Email:[e-mail]
 * @create 2020-04-30-16:29
 *
 */
public class Test {
    public static void main(String[] args) {
        String s = "123456789";
        System.out.println(s);
        Test t = new Test();
        String areturn = t.areturn(s, 3, 6);
        System.out.println(areturn);
    }

    public String areturn(String s, int a, int b) {
        char[] arr = s.toCharArray();
        String a1="", a2 = "", a3 = "";

        for (int i = 0; i < a-1; i++) {
            a1 = a1+arr[i];
        }
//        System.out.println(a1);
        for (int i = b; i < arr.length; i++) {
            a3 = a3+arr[i];
        }
//        System.out.println(a3);
        for (int i = b-1 ; i >a-2; i--) {
            a2 = a2+arr[i];
        }
//        System.out.println(a2);

        return a1+a2+a3;
    }
}

 

package com.yhqtv.exer;

/*
 *方法二
 *  @author  XMKJ  yhqtv.com Email:[e-mail]
 * @create 2020-05-01-10:33
 *
 */
public class StringDemo {

    public String reverse(String str,int startIndex,int endIndex){
        if(str!=null&&str.length()!=0){
            char[] arr = str.toCharArray();
            for (int x =startIndex,y=endIndex; x <y ; x++,y--) {
                char temp=arr[x];
                arr[x]=arr[y];
                arr[y]=temp;
            }
            return new String(arr);
        }
        return null;
    }

}