java字符串左移或右移几位（三次反转思想）

代码

public class StringReversal {
/**
* 反转字符串（循环交换）
* 其他字符串反转的方法
* 1、java的api：StringBuffer的reverse方法
* 2、利用栈的特性（先进后出）
* 3、反向遍历字符串
* @param from
* @return
*/
public static String reChange(String from){
char[] froms = from.toCharArray();
int length = froms.length;
for (int i = 0; i < length/2; i++){
char temp = froms[i];
froms[i] = froms[length - 1 -i];
froms[length - 1 -i] = temp;
}
return String.valueOf(froms);
}

/**
* 循环左移index位字符串
* 思想：先部分反转，后整体反转
* @param from
* @param index
* @return
*/
public static String leftMoveIndex(String from,int index){
String first = from.substring(0,index);
String second = from.substring(index);
first = reChange(first);
second = reChange(second);
from = first + second;
from = reChange(from);
return from;
}

/**
* 循环右移index位字符串
* 思想：先整体反转，后部分反转
* @param from
* @param index
* @return
*/
public static String rightMoveIndex(String from,int index){
from = reChange(from);
String first = from.substring(0,index);
String second = from.substring(index);
first = reChange(first);
second = reChange(second);
from = first + second;
return from;
}

public static void main(String[] args) {
String leftString = "abcdefg";
System.out.println("左移2位字符串结果："+leftMoveIndex(leftString,2));
String rightString = "abcdefg";
System.out.println("右移2位字符串结果："+rightMoveIndex(rightString,2));

}
}

输出结果

左移2位字符串结果：cdefgab
右移2位字符串结果：fgabcde