Java反转字符串的10种方法

package net.javaguides.corejava.string;
/**
* 
* @author ramesh fadatare
*
*/
public class reversewithstringconcat {
public static void main(string[] args) {
reversewithstringconcat concat = new reversewithstringconcat();
concat.reversewithstringconcat("javaguides");
}
private string reversewithstringconcat(string input) {
string output = new string();
for (int i = (input.length() - 1); i >= 0; i--) {
output += (input.charat(i));
}
display(input, output);
return output;
}
private void display(string input, string output) {
system.out.println(" input string :: " + input);
system.out.println(" output string :: " + output);
}
}

input string :: javaguides
output string :: sediugavaj

package net.javaguides.corejava.string;
/**
* 
* @author ramesh fadatare
*
*/
public class reversewithstringbuilderbuiltinmethod {
public static void main(string[] args) {
reversewithstringbuilderbuiltinmethod builtinmethod = new reversewithstringbuilderbuiltinmethod();
builtinmethod.reversewithstringbuilderbuiltinmethod("javaguides");
}
public string reversewithstringbuilderbuiltinmethod(string string) {
final stringbuilder builder = new stringbuilder(string);
display(string, builder.reverse().tostring());
return builder.reverse().tostring();
}
private void display(string input, string output) {
system.out.println(" input string :: " + input);
system.out.println(" output string :: " + output);
}
}

input string :: javaguides
output string :: sediugavaj

package net.javaguides.corejava.string;
/**
* 
* @author ramesh fadatare
*
*/
public class reversewithstringchatat{
public static void main(string[] args) {
reversewithstringchatat reversewithstringbuilder = new reversewithstringchatat();
reversewithstringbuilder.reversewithstringbuilder("javaguides");
}
public string reversewithstringchatat(string string) {
final stringbuilder builder = new stringbuilder();
for (int i = (string.length() - 1); i >= 0; i--) {
builder.append(string.charat(i));
}
display(string, builder.tostring());
return builder.tostring();
}
private void display(string input, string output) {
system.out.println(" input string :: " + input);
system.out.println(" output string :: " + output);
}
}

input string :: javaguides
output string :: sediugavaj

package net.javaguides.corejava.string;
/**
* 
* @author ramesh fadatare
*
*/
public class reversestringwithswaps {
public static void main(string[] args) {
reversestringwithswaps stringwithswaps = new reversestringwithswaps();
stringwithswaps.reversewithswaps("javaguides");
}
public string reversewithswaps(string string) {
final char[] array = string.tochararray();
final int length = array.length - 1;
final int half = (int) math.floor(array.length / 2);
char c;
for (int i = length; i >= half; i--) {
c = array[length - i];
array[length - i] = array[i];
array[i] = c;
}
display(string, string.valueof(array));
return string.valueof(array);
}
private void display(string input, string output) {
system.out.println(" input string :: " + input);
system.out.println(" output string :: " + output);
}
}

input string :: javaguides
output string :: sediugavaj

package net.javaguides.corejava.string;
/**
* 
* @author ramesh fadatare
*
*/
public class reversestringwithxor {
public static void main(string[] args) {
reversestringwithxor stringwithxor = new reversestringwithxor();
stringwithxor.reversewithxor("javaguides");
}
public string reversewithxor(string string) {
final char[] array = string.tochararray();
final int length = array.length;
final int half = (int) math.floor(array.length / 2);
for (int i = 0; i < half; i++) {
array[i] ^= array[length - i - 1];
array[length - i - 1] ^= array[i];
array[i] ^= array[length - i - 1];
}
display(string, string.valueof(array));
return string.valueof(array);
}
private void display(string input, string output) {
system.out.println(" input string :: " + input);
system.out.println(" output string :: " + output);
}
}

input string :: javaguides
output string :: sediugavaj

package net.javaguides.corejava.string;
import java.util.stack;
/**
* 
* @author ramesh fadatare
*
*/
public class reversestringusingstack {
// function to reverse a string in java using a stack and character array
public static string reverse(string str) {
// base case: if string is null or empty
if (str == null || str.equals(""))
return str;
// create an empty stack of characters
stack < character > stack = new stack < character > ();
// push every character of the given string into the stack
char[] ch = str.tochararray();
for (int i = 0; i < str.length(); i++)
stack.push(ch[i]);
// start from index 0
int k = 0;
// pop characters from the stack until it is empty
while (!stack.isempty()) {
// assign each popped character back to the character array
ch[k++] = stack.pop();
}
// convert the character array into string and return it
return string.copyvalueof(ch);
}
public static void main(string[] args) {
string str = "javaguides";
str = reverse(str); // string is immutable
system.out.println("reverse of the given string is : " + str);
}
}

reverse of the given string is : sediugavaj

package net.javaguides.corejava.string;
import java.util.arraylist;
import java.util.collections;
import java.util.list;
/**
* 
* @author ramesh fadatare
*
*/
public class reversestringusingcollectionsreversemethod {
// function to reverse a string in java using collections.reverse()
public static string reverse(string str) {
// base case: if string is null or empty
if (str == null || str.equals(""))
return str;
// create an empty list of characters
list < character > list = new arraylist < character > ();
// push every character of the given string into it
for (char c: str.tochararray())
list.add(c);
// reverse list using java.util.collections reverse()
collections.reverse(list);
// covert arraylist into string using stringbuilder and return it
stringbuilder builder = new stringbuilder(list.size());
for (character c: list)
builder.append(c);
return builder.tostring();
}
public static void main(string[] args) {
string str = "java guides";
// string is immutable
str = reverse(str);
system.out.println("reverse of the given string is : " + str);
}
}

reverse of the given string is : sediug avaj

package net.javaguides.corejava.string;
/**
* 
* @author ramesh fadatare
*
*/
public class reversestringusingbytearray {
// function to reverse a string in java using byte array
public static string reverse(string str) {
// return if string is null or empty
if (str == null || str.equals(""))
return str;
// convert string into bytes
byte[] bytes = str.getbytes();
// start from the two end points l and h of the given string
// and increment l & decrement h at each iteration of the loop
// until two end-points intersect (l >= h)
for (int l = 0, h = str.length() - 1; l < h; l++, h--) {
// swap values at l and h
byte temp = bytes[l];
bytes[l] = bytes[h];
bytes[h] = temp;
}
// convert byte array back into the string
return new string(bytes);
}
public static void main(string[] args) {
string str = "java guides";
// string is immutable
str = reverse(str);
system.out.println("reverse of the given string is : " + str);
}
}

reverse of the given string is : sediug avaj

package net.javaguides.corejava.string;
/**
* 
* @author ramesh fadatare
*
*/
public class usingsubstringfunction {
// function to reverse a string in java using recursion
private static string reverse(string str) {
// base case: if string is null or empty
if (str == null || str.equals(""))
return str;
// last character + recurse for remaining string
return str.charat(str.length() - 1) + reverse(str.substring(0, str.length() - 1));
}
public static void main(string[] args) {
string str = "javaguides";
// string is immutable
str = reverse(str);
system.out.println("reverse of the given string is : " + str);
}
}

reverse of the given string is : sediugavaj

package net.javaguides.corejava.string;
/**
* 
* @author ramesh fadatare
*
*/
public class usingrecursion {
static int i = 0;
// recursive function to reverse a string in java using static variable
private static void reverse(char[] str, int k) {
// if we have reached the end of the string
if (k == str.length)
return;
// recurse for next character
reverse(str, k + 1);
if (i <= k) {
char temp = str[k];
str[k] = str[i];
str[i++] = temp;
}
}
public static string reverse(string str) {
// base case: if string is null or empty
if (str == null || str.equals(""))
return str;
// convert string into a character array
char[] a = str.tochararray();
// reverse character array
reverse(a, 0);
// convert character array into the string
return string.copyvalueof(a);
}
public static void main(string[] args) {
string str = "java guides";
// string is immutable
str = reverse(str);
system.out.println("reverse of the given string is : " + str);
}
}

reverse of the given string is : sediug avaj