这里介绍Java中5中实现String反转的方式。
一、数组实现String反转
//数组实现String反转
public String reverseByArray(){
if(str == null || str.length() == 1){
return null;
}
char[] ch = str.toCharArray();//字符串转换成字符数组
for(int i = 0 ; i < ch.length/2 ; i++){
char temp = ch[i];
ch[i] = ch[ch.length-i-1];
ch[ch.length-i-1] = temp;
}
return new String(ch);
}
二、栈实现String反转
//用栈实现String反转
public String reverseByStack(){
if(str == null || str.length() == 1){
return null;
}
Stack<Character> stack = new Stack<Character>();
char[] ch = str.toCharArray();//字符串转换成字符数组
for (char c : ch) {
stack.push(c);//每个字符，推进栈
}
for (int i = 0; i < ch.length; i++) {
ch[i] = stack.pop();//移除这个堆栈的顶部对象
}
return new String(ch);
}
三、逆序遍历实现String反转
//用逆序遍历实现String反转
public String reverseBySort(){
if(str == null || str.length() == 1){
return null;
}
StringBuffer sb = new StringBuffer();
for (int i = str.length() -1 ; i >= 0; i--) {
sb.append(str.charAt(i));//使用StringBuffer从右往左拼接字符
}
return sb.toString();
}四、位运算实现String反转
//使用位运算实现String反转
public String reverseByBit() {
if(str == null || str.length() == 1){
return null;
}
char[] ch = str.toCharArray();//字符串转换成字符数组
int len = str.length();
for(int i= 0; i< len/ 2; i++) {
ch[i]^= ch[len- 1- i];
ch[len- 1- i]^= ch[i];
ch[i]^= ch[len- 1- i];
}
return new String(ch);
}
五、递归实现String反转
//使用递归实现String反转
public String reverseByRecursive(String str){
if(str == null || str.length() == 0){
return null;
}
if(str.length() == 1){
return str;
} else {
//从下标为1开始截取字符串，在返回下标为0的字符
return reverseByRecursive(str.substring(1)) + str.charAt(0);
}
}
六、测试
public class Test {
public static void main(String[] args) {
String s = "123456";
Reverse r = new Reverse(s);
System.out.println(r.reverseByArray());
System.out.println(r.reverseByStack());
System.out.println(r.reverseBySort());
System.out.println(r.reverseByBit());
System.out.println(r.reverseByRecursive(s));
}
} 七、结果
八、用于String反转的全部代码
public class Reverse {
private String str = null;
public Reverse(String str){
this.str = str;
}
//数组实现String反转
public String reverseByArray(){
if(str == null || str.length() == 1){
return null;
}
char[] ch = str.toCharArray();//字符串转换成字符数组
for(int i = 0 ; i < ch.length/2 ; i++){
char temp = ch[i];
ch[i] = ch[ch.length-i-1];
ch[ch.length-i-1] = temp;
}
return new String(ch);
}
//用栈实现String反转
public String reverseByStack(){
if(str == null || str.length() == 1){
return null;
}
Stack<Character> stack = new Stack<Character>();
char[] ch = str.toCharArray();//字符串转换成字符数组
for (char c : ch) {
stack.push(c);//每个字符，推进栈
}
for (int i = 0; i < ch.length; i++) {
ch[i] = stack.pop();//移除这个堆栈的顶部对象
}
return new String(ch);
}
//用逆序遍历实现String反转
public String reverseBySort(){
if(str == null || str.length() == 1){
return null;
}
StringBuffer sb = new StringBuffer();
for (int i = str.length() -1 ; i >= 0; i--) {
sb.append(str.charAt(i));//使用StringBuffer从右往左拼接字符
}
return sb.toString();
}
//使用位运算实现String反转
public String reverseByBit() {
if(str == null || str.length() == 1){
return null;
}
char[] ch = str.toCharArray();//字符串转换成字符数组
int len = str.length();
for(int i= 0; i< len/ 2; i++) {
ch[i]^= ch[len- 1- i];
ch[len- 1- i]^= ch[i];
ch[i]^= ch[len- 1- i];
}
return new String(ch);
}
//使用递归实现String反转
public String reverseByRecursive(String str){
if(str == null || str.length() == 0){
return null;
}
if(str.length() == 1){
return str;
} else {
//从下标为1开始截取字符串，在返回下标为0的字符
return reverseByRecursive(str.substring(1)) + str.charAt(0);
}
}
} 全部代码