blocks|key|769600|text|您可以使用以下命令：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|769601|new+StringBuilder(hi).reverse().toString()|code-block|syntax|javascript|769602|StringBuilder是在Java5中添加的。对于Java5之前的版本，可以使用StringBuffer类-它具有相同的接口。|offset|length|style|CODE|769603|entityMap^0|0|0|0|D|16|C|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

You can use this:
<pre class="lang-java prettyprint-override"><code>new StringBuilder(hi).reverse().toString()
</code></pre>
<code>StringBuilder</code> was added in Java 5. For versions prior to Java 5, the <code>StringBuffer</code> class can be used instead — it has the same API.

blocks|key|552948|text|public+static+String+reverseIt(String+source)+{
++++int+i,+len+=+source.length();
++++StringBuilder+dest+=+new+StringBuilder(len);

++++for+(i+=+(len+-+1);+i+>=+0;+i--){
++++++++dest.append(source.charAt(i));
++++}

++++return+dest.toString();
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|552949|http://www.java2s.com/Code/Java/Language-Basics/ReverseStringTest.htm|unstyled|offset|length|552950|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|1X|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|Q|8|@]|9|@$G|R|H|S|1|T]]|A|$]]|$1|I|3|-4|5|F|7|U|8|@]|9|@]|A|$]]]|J|$K|$5|L|M|N|A|$O|E]]]]

<pre><code>public static String reverseIt(String source) {
 int i, len = source.length();
 StringBuilder dest = new StringBuilder(len);

 for (i = (len - 1); i &gt;= 0; i--){
 dest.append(source.charAt(i));
 }

 return dest.toString();
}
</code></pre>

<a href="http://www.java2s.com/Code/Java/Language-Basics/ReverseStringTest.htm" rel="noreferrer">http://www.java2s.com/Code/Java/Language-Basics/ReverseStringTest.htm</a>

blocks|key|553003|text|String+string="whatever";
String+reverse+=+new+StringBuffer(string).reverse().toString();
System.out.println(reverse);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|553004|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>String string="whatever";
String reverse = new StringBuffer(string).reverse().toString();
System.out.println(reverse);
</code></pre>

blocks|key|769665|text|看看StringBuffer下的Java6API|type|unstyled|depth|inlineStyleRanges|entityRanges|data|769666|String+s+=+"sample";
String+result+=+new+StringBuffer(s).reverse().toString();|code-block|syntax|javascript|769667|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Take a look at the Java 6 API under StringBuffer

<pre><code>String s = "sample";
String result = new StringBuffer(s).reverse().toString();
</code></pre>

blocks|key|769783|text|下面是一个使用递归的示例：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|769784|public+void+reverseString()+{
++++String+alphabet+=+"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
++++String+reverseAlphabet+=+reverse(alphabet,+alphabet.length()-1);
}

String+reverse(String+stringToReverse,+int+index){
++++if(index+==+0){
++++++++return+stringToReverse.charAt(0)+%2B+"";
++++}

++++char+letter+=+stringToReverse.charAt(index);
++++return+letter+%2B+reverse(stringToReverse,+index-1);
}|code-block|syntax|javascript|769785|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here is an example using recursion:

<pre><code>public void reverseString() {
 String alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 String reverseAlphabet = reverse(alphabet, alphabet.length()-1);
}

String reverse(String stringToReverse, int index){
 if(index == 0){
 return stringToReverse.charAt(0) + "";
 }

 char letter = stringToReverse.charAt(index);
 return letter + reverse(stringToReverse, index-1);
}
</code></pre>

blocks|key|770155|text|下面是一个低级别的解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|770156|import+java.util.Scanner;

public+class+class1+{

++++public+static+void+main(String[]+args)+{
++++++++Scanner+in+=+new+Scanner(System.in);
++++++++String+inpStr+=+in.nextLine();
++++++++System.out.println("Original+String+:"+%2B+inpStr);
++++++++char+temp;
++++++++char[]+arr+=+inpStr.toCharArray();
++++++++int+len+=+arr.length;
++++++++for(int+i=0;+i<(inpStr.length())/2;+i%2B%2B,len--){
++++++++++++temp+=+arr[i];
++++++++++++arr[i]+=+arr[len-1];
++++++++++++arr[len-1]+=+temp;
++++++++}

++++++++System.out.println("Reverse+String+:"+%2B+String.valueOf(arr));
++++}
}|code-block|syntax|javascript|770157|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here is a low level solution:

<pre><code>import java.util.Scanner;

public class class1 {

 public static void main(String[] args) {
 Scanner in = new Scanner(System.in);
 String inpStr = in.nextLine();
 System.out.println("Original String :" + inpStr);
 char temp;
 char[] arr = inpStr.toCharArray();
 int len = arr.length;
 for(int i=0; i&lt;(inpStr.length())/2; i++,len--){
 temp = arr[i];
 arr[i] = arr[len-1];
 arr[len-1] = temp;
 }

 System.out.println("Reverse String :" + String.valueOf(arr));
 }
}
</code></pre>

blocks|key|553611|text|我试过了，只是为了好玩，使用了Stack。下面是我的代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|553612|public+String+reverseString(String+s)+{
++++Stack<Character>+stack+=+new+Stack<>();
++++StringBuilder+sb+=+new+StringBuilder();
++++for+(int+i+=+0;+i+<+s.length();+i%2B%2B)+{
++++++++stack.push(s.charAt(i));
++++}
++++while+(!stack.empty())+{
++++++++sb.append(stack.pop());
++++}
++++return+sb.toString();

}|code-block|syntax|javascript|553613|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I tried, just for fun, by using a Stack. Here my code:

<pre><code>public String reverseString(String s) {
 Stack&lt;Character&gt; stack = new Stack&lt;&gt;();
 StringBuilder sb = new StringBuilder();
 for (int i = 0; i &lt; s.length(); i++) {
 stack.push(s.charAt(i));
 }
 while (!stack.empty()) {
 sb.append(stack.pop());
 }
 return sb.toString();

}
</code></pre>

blocks|key|770049|text|它用最少的代码行是非常简单的|type|unstyled|depth|inlineStyleRanges|entityRanges|data|770050|public+class+ReverseString+{
++++public+static+void+main(String[]+args)+{
++++++++String+s1+=+"neelendra";
++++++++for(int+i=s1.length()-1;i>=0;i--)
++++++++++++{
++++++++++++++++System.out.print(s1.charAt(i));
++++++++++++}
++++}
}|code-block|syntax|javascript|770051|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

It is very simple in minimum code of lines

<pre><code>public class ReverseString {
 public static void main(String[] args) {
 String s1 = "neelendra";
 for(int i=s1.length()-1;i&gt;=0;i--)
 {
 System.out.print(s1.charAt(i));
 }
 }
}
</code></pre>

blocks|key|553741|text|这对我来说很管用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|553742|public+static+void+main(String[]+args)+{

++++String+text+=+"abcdefghijklmnopqrstuvwxyz";

++++for+(int+i+=+(text.length()+-+1);+i+>=+0;+i--)+{
++++++++System.out.print(text.charAt(i));
++++}
}|code-block|syntax|javascript|553743|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This did the trick for me

<pre><code>public static void main(String[] args) {

 String text = "abcdefghijklmnopqrstuvwxyz";

 for (int i = (text.length() - 1); i &gt;= 0; i--) {
 System.out.print(text.charAt(i));
 }
}
</code></pre>

blocks|key|769718|text|System.out.print("Please+enter+your+name:+");
String+name+=+keyboard.nextLine();

String+reverse+=+new+StringBuffer(name).reverse().toString();
String+rev+=+reverse.toLowerCase();
System.out.println(rev);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|769719|我使用此方法将名称反向转换为小写。|unstyled|769720|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>System.out.print("Please enter your name: ");
String name = keyboard.nextLine();

String reverse = new StringBuffer(name).reverse().toString();
String rev = reverse.toLowerCase();
System.out.println(rev);
</code></pre>

I used this method to turn names backwards and into lower case.

blocks|key|769920|text|反转String的一种自然方法是使用StringTokenizer和堆栈。Stack是一个实现易于使用的后进先出(LIFO)对象堆栈的类。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|769921|String+s+=+"Hello+My+name+is+Sufiyan";|code-block|syntax|javascript|769922|把它放在堆栈的前面|769923|Stack<String>+myStack+=+new+Stack<>();
StringTokenizer+st+=+new+StringTokenizer(s);
while+(st.hasMoreTokens())+{
+++++myStack.push(st.nextToken());
}|769924|向后打印堆栈|769925|System.out.print('"'+%2B+s+%2B+'"'+%2B+"+backwards+by+word+is:\n\t\"");
while+(!myStack.empty())+{
++System.out.print(myStack.pop());
++System.out.print('+');
}

System.out.println('"');|769926|entityMap^0|2|6|I|F|11|5|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|12|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|14|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|15|8|@]|D|@]|E|$I|J]]|$1|S|3|-4|5|6|7|16|8|@]|D|@]|E|$]]]|T|$]]

One natural way to reverse a <code>String</code> is to use a <code>StringTokenizer</code> and a stack. <code>Stack</code> is a class that implements an easy-to-use last-in, first-out (LIFO) stack of objects.

<pre><code>String s = "Hello My name is Sufiyan";
</code></pre>

Put it in the stack frontwards

<pre><code>Stack&lt;String&gt; myStack = new Stack&lt;&gt;();
StringTokenizer st = new StringTokenizer(s);
while (st.hasMoreTokens()) {
 myStack.push(st.nextToken());
}
</code></pre>

Print the stack backwards

<pre><code>System.out.print('"' + s + '"' + " backwards by word is:\n\t\"");
while (!myStack.empty()) {
 System.out.print(myStack.pop());
 System.out.print(' ');
}

System.out.println('"');
</code></pre>

blocks|key|769749|text|++++public+String+reverse(String+s)+{

++++++++String+reversedString+=+"";
++++++++for(int+i=s.length();+i>0;+i--)+{
++++++++++++reversedString+%2B=+s.charAt(i-1);
++++++++}+++

++++++++return+reversedString;
++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|769750|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> public String reverse(String s) {

 String reversedString = "";
 for(int i=s.length(); i&gt;0; i--) {
 reversedString += s.charAt(i-1);
 } 

 return reversedString;
 }
</code></pre>

blocks|key|769796|text|您还可以尝试执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|769797|public+class+StringReverse+{
++++public+static+void+main(String[]+args)+{
++++++++String+str+=+"Dogs+hates+cats";
++++++++StringBuffer+sb+=+new+StringBuffer(str);
++++++++System.out.println(sb.reverse());
++++}
}|code-block|syntax|javascript|769798|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can also try this:

<pre><code>public class StringReverse {
 public static void main(String[] args) {
 String str = "Dogs hates cats";
 StringBuffer sb = new StringBuffer(str);
 System.out.println(sb.reverse());
 }
}
</code></pre>

blocks|key|553472|text|public+class+Test+{

public+static+void+main(String+args[])+{
+++StringBuffer+buffer+=+new+StringBuffer("Game+Plan");
+++buffer.reverse();
+++System.out.println(buffer);
+}++
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|553473|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>public class Test {

public static void main(String args[]) {
 StringBuffer buffer = new StringBuffer("Game Plan");
 buffer.reverse();
 System.out.println(buffer);
 } 
}
</code></pre>

blocks|key|770281|text|上面所有的解决方案都太好了，但我在这里使用递归编程来制作反向字符串。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|770282|这对那些正在寻找递归方式做反向字符串的人很有帮助。|770283|public+class+ReversString+{

public+static+void+main(String+args[])+{
++++char+s[]+=+"Dhiral+Pandya".toCharArray();
++++String+r+=+new+String(reverse(0,+s));
++++System.out.println(r);
}

public+static+char[]+reverse(int+i,+char+source[])+{

++++if+(source.length+/+2+==+i)+{
++++++++return+source;
++++}

++++char+t+=+source[i];
++++source[i]+=+source[source.length+-+1+-+i];
++++source[source.length+-+1+-+i]+=+t;

++++i%2B%2B;
++++return+reverse(i,+source);

}

}|code-block|syntax|javascript|770284|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

All above solution is too good but here I am making reverse string using recursive programming. 

This is helpful for who is looking recursive way of doing reverse string. 

<pre><code>public class ReversString {

public static void main(String args[]) {
 char s[] = "Dhiral Pandya".toCharArray();
 String r = new String(reverse(0, s));
 System.out.println(r);
}

public static char[] reverse(int i, char source[]) {

 if (source.length / 2 == i) {
 return source;
 }

 char t = source[i];
 source[i] = source[source.length - 1 - i];
 source[source.length - 1 - i] = t;

 i++;
 return reverse(i, source);

}

}
</code></pre>

blocks|key|769679|text|public+static+void+main(String[]+args)+{
++++String+str+=+"Prashant";
++++int+len+=+str.length();
++++char[]+c+=+new+char[len];
++++for+(int+j+=+len+-+1,+i+=+0;+j+>=+0;+j--,+i%2B%2B)+{
++++++++c[i]+=+str.charAt(j);
++++}
++++str+=+String.copyValueOf(c);
++++System.out.println(str);
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|769680|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>public static void main(String[] args) {
 String str = "Prashant";
 int len = str.length();
 char[] c = new char[len];
 for (int j = len - 1, i = 0; j &gt;= 0; j--, i++) {
 c[i] = str.charAt(j);
 }
 str = String.copyValueOf(c);
 System.out.println(str);
}
</code></pre>

blocks|key|553405|text|它获取您键入的值，并返回相反的值;)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|553406|public+static++String+reverse+(String+a){
++++char[]+rarray+=+a.toCharArray();
++++String+finalvalue+=+"";
++++for+(int+i+=+0;+i+<+rarray.length;+i%2B%2B)
++++{
++++++++finalvalue+%2B=+rarray[rarray.length+-+1+-+i];
++++}+++
return+finalvalue;|code-block|syntax|javascript|553407|}|553408|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

It gets the value you typed and returns it reversed ;)

<pre><code>public static String reverse (String a){
 char[] rarray = a.toCharArray();
 String finalvalue = "";
 for (int i = 0; i &lt; rarray.length; i++)
 {
 finalvalue += rarray[rarray.length - 1 - i];
 } 
return finalvalue;
</code></pre>

}

blocks|key|770110|text|公共String+reverseWords(String+s)+{|type|unstyled|depth|inlineStyleRanges|entityRanges|data|770111|++++String+reversedWords+=+"";

++++if(s.length()<=0)+{
++++++++return+reversedWords;
++++}else+if(s.length()+==+1){
++++++++if(s+==+"+"){
++++++++++++return+"";
++++++++}
++++++++return+s;
++++}

++++char+arr[]+=+s.toCharArray();
++++int+j+=+arr.length-1;
++++while(j+>=+0+){
++++++++if(+arr[j]+==+'+'){
++++++++++++reversedWords%2B=arr[j];
++++++++}else{
++++++++++++String+temp="";
++++++++++++while(j>=0+&&+arr[j]+!=+'+'){
++++++++++++++++temp%2B=arr[j];
++++++++++++++++j--;
++++++++++++}
++++++++++++j%2B%2B;
++++++++++++temp+=+reverseWord(temp);
++++++++++++reversedWords%2B=temp;
++++++++}
++++++++j--;

++++}

++++String[]+chk+=+reversedWords.split("+");

++++if(chk+==+null+%7C%7C+chk.length+==+0){
++++++++return+"";
++++}

++++return+reversedWords;



}

public+String+reverseWord(String+s){

++++char[]+arr+=+s.toCharArray();

++++for(int+i=0,j=arr.length-1;i<=j;i%2B%2B,j--){
++++++++char+tmp+=+arr[i];
++++++++arr[i]+=+arr[j];
++++++++arr[j]+=+tmp;
++++}
++++return+String.valueOf(arr);

}|code-block|syntax|javascript|770112|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

public String reverseWords(String s) {

<pre><code> String reversedWords = "";

 if(s.length()&lt;=0) {
 return reversedWords;
 }else if(s.length() == 1){
 if(s == " "){
 return "";
 }
 return s;
 }

 char arr[] = s.toCharArray();
 int j = arr.length-1;
 while(j &gt;= 0 ){
 if( arr[j] == ' '){
 reversedWords+=arr[j];
 }else{
 String temp="";
 while(j&gt;=0 &amp;&amp; arr[j] != ' '){
 temp+=arr[j];
 j--;
 }
 j++;
 temp = reverseWord(temp);
 reversedWords+=temp;
 }
 j--;

 }

 String[] chk = reversedWords.split(" ");

 if(chk == null || chk.length == 0){
 return "";
 }

 return reversedWords;



}

public String reverseWord(String s){

 char[] arr = s.toCharArray();

 for(int i=0,j=arr.length-1;i&lt;=j;i++,j--){
 char tmp = arr[i];
 arr[i] = arr[j];
 arr[j] = tmp;
 }
 return String.valueOf(arr);

}
</code></pre>

blocks|key|770244|text|只是为了好玩..：)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|770245|Algorithm+(str,len):
++char+reversedStr[]+=new+reversedStr[len]
++Traverse+i+from+0+to+len/2+and+then
++++reversedStr[i]=str[len-1-i]++
++++reversedStr[len-1=i]=str[i]
++return+reversedStr;|code-block|syntax|javascript|770246|时间复杂度:O(n)空间复杂度:O(N)|770247|+public+class+Reverse+{
++++static+char+reversedStr[];++++
++++public+static+void+main(String[]+args)+{
++++++++System.out.println(reversestr("jatin"));
++++}++++++++
++++private+static+String+reversestr(String+str)+{
++++++++int+strlen+=+str.length();
++++++++reversedStr+=+new+char[strlen];
++++++++
++++++++for+(int+i+=+0;+i+<=+strlen+/+2;+i%2B%2B)+{
++++++++++++reversedStr[i]+=+str.charAt(strlen+-+1+-+i);
++++++++++++reversedStr[strlen+-+1+-+i]+=+str.charAt(i);

++++++++}
++++++++return+new+String(reversedStr);
++++}

}|770248|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Just For Fun..:) 
<pre><code>Algorithm (str,len):
 char reversedStr[] =new reversedStr[len]
 Traverse i from 0 to len/2 and then
 reversedStr[i]=str[len-1-i] 
 reversedStr[len-1=i]=str[i]
 return reversedStr;
</code></pre>
Time Complexity:O(n)
Space Complexity :O(n)
<pre><code> public class Reverse {
 static char reversedStr[]; 
 public static void main(String[] args) {
 System.out.println(reversestr(&quot;jatin&quot;));
 } 
 private static String reversestr(String str) {
 int strlen = str.length();
 reversedStr = new char[strlen];
 
 for (int i = 0; i &lt;= strlen / 2; i++) {
 reversedStr[i] = str.charAt(strlen - 1 - i);
 reversedStr[strlen - 1 - i] = str.charAt(i);

 }
 return new String(reversedStr);
 }

}
</code></pre>

blocks|key|553731|text|public+void+reverString(){
System.out.println("Enter+value");
BufferedReader+br=new+BufferedReader(new+InputStreamReader(System.in));
+try{

++String+str=br.readLine();
++char[]+charArray=str.toCharArray();
++for(int+i=charArray.length-1;+i>=0;+i--){
+++System.out.println(charArray[i]);
++}
++}
+++catch(IOException+ex){
++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|553732|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>public void reverString(){
System.out.println("Enter value");
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
 try{

 String str=br.readLine();
 char[] charArray=str.toCharArray();
 for(int i=charArray.length-1; i&gt;=0; i--){
 System.out.println(charArray[i]);
 }
 }
 catch(IOException ex){
 }
</code></pre>

blocks|key|553761|text|递归：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|553762|+public+String+stringReverse(String+string)+{
++++if+(string+==+null+%7C%7C+string.length()+==+0)+{
++++++++return+string;
++++}
++++return+stringReverse(string.substring(1))+%2B+string.charAt(0);
+}|code-block|syntax|javascript|553763|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

recursion:

<pre><code> public String stringReverse(String string) {
 if (string == null || string.length() == 0) {
 return string;
 }
 return stringReverse(string.substring(1)) + string.charAt(0);
 }
</code></pre>

blocks|key|553790|text|public+static+String+revString(String+str){
++++char[]+revCharArr+=+str.toCharArray();
++++for+(int+i=0;+i<+str.length()/2;+i%2B%2B){
++++++++char+f+=+revCharArr[i];
++++++++char+l+=+revCharArr[str.length()-i-1];
++++++++revCharArr[i]+=+l;
++++++++revCharArr[str.length()-i-1]+=+f;
++++}
++++String+revStr+=+new+String(revCharArr);
++++return+revStr;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|553791|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>public static String revString(String str){
 char[] revCharArr = str.toCharArray();
 for (int i=0; i&lt; str.length()/2; i++){
 char f = revCharArr[i];
 char l = revCharArr[str.length()-i-1];
 revCharArr[i] = l;
 revCharArr[str.length()-i-1] = f;
 }
 String revStr = new String(revCharArr);
 return revStr;
}
</code></pre>

blocks|key|553793|text|++++public+static+void+reverseString(String+s){
++++++++System.out.println("---------");
++++++++for(int+i=s.length()-1;+i>=0;i--){
++++++++++++System.out.print(s.charAt(i));++++
++++++++}
++++++++System.out.println();+

++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|553794|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> public static void reverseString(String s){
 System.out.println("---------");
 for(int i=s.length()-1; i&gt;=0;i--){
 System.out.print(s.charAt(i)); 
 }
 System.out.println(); 

 }
</code></pre>

blocks|key|770371|text|++++//Solution+#1+--+Using+array+and+charAt()
++++String+name+=+"reverse";+//String+to+reverse
++++Character[]+nameChar+=++new+Character[name.length()];+//+Declaring+a+character+array+with+length+as+length+of+the+String+which+you+want+to+reverse.
++++for(int+i=0;i<name.length();i%2B%2B)//+this+will+loop+you+through+the+String
++++nameChar[i]=name.charAt(name.length()-1-i);//+Using+built+in+charAt()+we+can+fetch+the+character+at+a+given+index.+
++++for(char+nam:nameChar)//+Just+to+print+the+above+nameChar+character+Array+using+an+enhanced+for+loop
++++System.out.print(nam);


++++//Solution+#2+-+Using+StringBuffer+and+reverse+().
++++StringBuffer+reverseString+=+new+StringBuffer("reverse");
++++System.out.println(reverseString.reverse());+//reverse+()+Causes+the+character+sequence+to+be+replaced+by+the+reverse+of+the+sequence.|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|770372|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> //Solution #1 -- Using array and charAt()
 String name = "reverse"; //String to reverse
 Character[] nameChar = new Character[name.length()]; // Declaring a character array with length as length of the String which you want to reverse.
 for(int i=0;i&lt;name.length();i++)// this will loop you through the String
 nameChar[i]=name.charAt(name.length()-1-i);// Using built in charAt() we can fetch the character at a given index. 
 for(char nam:nameChar)// Just to print the above nameChar character Array using an enhanced for loop
 System.out.print(nam);


 //Solution #2 - Using StringBuffer and reverse ().
 StringBuffer reverseString = new StringBuffer("reverse");
 System.out.println(reverseString.reverse()); //reverse () Causes the character sequence to be replaced by the reverse of the sequence.
</code></pre>

blocks|key|554136|text|使用charAt()方法|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|554137|++++String+name+=+"gaurav";
++++String+reversedString+=+"";
++++
++++for(int+i+=+name.length()-1;+i>=0;+i--){
++++++reversedString+=+reversedString+%2B+name.charAt(i);
++++}
++++System.out.println(reversedString);|code-block|syntax|javascript|554138|使用toCharArray()方法|554139|String+name+=+"gaurav";
++++char+[]+stringCharArray+=+name.toCharArray();
++++String+reversedString+=+"";
++++
++++for(int+i+=+stringCharArray.length-1;+i>=0;+i--)+{
++++++reversedString+=+reversedString+%2B+stringCharArray[i];
++++}
++++System.out.println(reversedString);|554140|使用Stringbuilder的reverse()方法|554141|++++String+name+=+"gaurav";
++++
++++String+reversedString+=+new+StringBuilder(name).reverse().toString();
++++
++++System.out.println(reversedString);|554142|检查https://coderolls.com/reverse-a-string-in-java/|554143|entityMap|0|LINK|mutability|MUTABLE|url|https://coderolls.com/reverse-a-string-in-java/^0|2|8|0|0|2|D|0|0|G|9|0|0|2|1B|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|15|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|16|8|@$9|17|A|18|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|19|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|H|7|1D|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|1E|8|@]|D|@$9|1F|A|1G|1|1H]]|E|$]]|$1|U|3|-4|5|6|7|1I|8|@]|D|@]|E|$]]]|V|$W|$5|X|Y|Z|E|$10|11]]]]

<h1>Using <code>charAt()</code> method</h1>
<pre class="lang-java prettyprint-override"><code> String name = &quot;gaurav&quot;;
 String reversedString = &quot;&quot;;
 
 for(int i = name.length()-1; i&gt;=0; i--){
 reversedString = reversedString + name.charAt(i);
 }
 System.out.println(reversedString);
</code></pre>
<h1>Using <code>toCharArray()</code> method</h1>
<pre class="lang-java prettyprint-override"><code>String name = &quot;gaurav&quot;;
 char [] stringCharArray = name.toCharArray();
 String reversedString = &quot;&quot;;
 
 for(int i = stringCharArray.length-1; i&gt;=0; i--) {
 reversedString = reversedString + stringCharArray[i];
 }
 System.out.println(reversedString);
</code></pre>
<h1>Using <code>reverse()</code> method of the Stringbuilder</h1>
<pre class="lang-java prettyprint-override"><code> String name = &quot;gaurav&quot;;
 
 String reversedString = new StringBuilder(name).reverse().toString();
 
 System.out.println(reversedString);
</code></pre>
Check <a href="https://coderolls.com/reverse-a-string-in-java/" rel="nofollow noreferrer">https://coderolls.com/reverse-a-string-in-java/</a>

blocks|key|553288|text|import+java.util.Scanner;

public+class+Test+{

++++public+static+void+main(String[]+args){
++++++++Scanner+input+=+new+Scanner+(System.in);
++++++++String+word+=+input.next();
++++++++String+reverse+=+"";
++++++++for(int+i=word.length()-1;+i>=0;+i--)
++++++++++++reverse+%2B=+word.charAt(i);
++++++++System.out.println(reverse);++++++++
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|553289|如果你想使用一个简单的for循环！|unstyled|553290|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>import java.util.Scanner;

public class Test {

 public static void main(String[] args){
 Scanner input = new Scanner (System.in);
 String word = input.next();
 String reverse = "";
 for(int i=word.length()-1; i&gt;=0; i--)
 reverse += word.charAt(i);
 System.out.println(reverse); 
 }
}
</code></pre>

If you want to use a simple for loop!

blocks|key|769875|text|package+logicprogram;
import+java.io.*;

public+class+Strinrevers+{
public+static+void+main(String+args[])throws+IOException
{
++++BufferedReader+br=new+BufferedReader(new+InputStreamReader(System.in));
++++System.out.println("enter+data");
++++String+data=br.readLine();
++++System.out.println(data);
++++String+str="";
++++char+cha[]=data.toCharArray();

++++int+l=data.length();
++++int+k=l-1;
++++System.out.println(l);


++++for(int+i=0;k>=i;k--)
++++{

++++++++str%2B=cha[k];


++++}
++++//String+text=String.valueOf(ch);
++++System.out.println(str);

}

}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|769876|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>package logicprogram;
import java.io.*;

public class Strinrevers {
public static void main(String args[])throws IOException
{
 BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
 System.out.println("enter data");
 String data=br.readLine();
 System.out.println(data);
 String str="";
 char cha[]=data.toCharArray();

 int l=data.length();
 int k=l-1;
 System.out.println(l);


 for(int i=0;k&gt;=i;k--)
 {

 str+=cha[k];


 }
 //String text=String.valueOf(ch);
 System.out.println(str);

}

}
</code></pre>

blocks|key|553701|text|StringBuilder+s+=+new+StringBuilder("racecar");
++++for+(int+i+=+0,+j+=+s.length()+-+1;+i+<+(s.length()/2);+i%2B%2B,+j--)+{
++++++++char+temp+=+s.charAt(i);
++++++++s.setCharAt(i,+s.charAt(j));
++++++++s.setCharAt(j,+temp);
++++}

++++System.out.println(s.toString());|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|553702|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>StringBuilder s = new StringBuilder("racecar");
 for (int i = 0, j = s.length() - 1; i &lt; (s.length()/2); i++, j--) {
 char temp = s.charAt(i);
 s.setCharAt(i, s.charAt(j));
 s.setCharAt(j, temp);
 }

 System.out.println(s.toString());
</code></pre>

blocks|key|770367|text|java中简单的For循环|type|unstyled|depth|inlineStyleRanges|entityRanges|data|770368|+public+void+reverseString(char[]+s)+{
++++int+length+=+s.length;
++++for+(int+i+=+0;+i+<+s.length+/+2;+i%2B%2B)+{
++++++++//+swaping+character
++++++++char+temp+=+s[length+-+i+-+1];
++++++++s[length+-+i+-+1]+=+s[i];
++++++++s[i]+=+temp;
++++}
}|code-block|syntax|javascript|770369|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Simple For loop in java

<pre><code> public void reverseString(char[] s) {
 int length = s.length;
 for (int i = 0; i &lt; s.length / 2; i++) {
 // swaping character
 char temp = s[length - i - 1];
 s[length - i - 1] = s[i];
 s[i] = temp;
 }
}
</code></pre>

blocks|key|770374|text|package+ThingsInArray;

public+class+MagicWithSelectionSort+{

++++public+static+void+main(String[]+arg)+{
++++++++isSort("uhsnamiH");
++++}

++++private+static+void+isSort(String+name)+{
++++++++String+revName="";
++++++++for+(int+i+=+name.toCharArray().length-1;+i+>0+;+i--)+{
++++++++++++revName=revName%2Bname.charAt(i);
++++++++}
++++++++System.out.println(revName);
++++}

}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|770375|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre class="lang-java prettyprint-override"><code>package ThingsInArray;

public class MagicWithSelectionSort {

 public static void main(String[] arg) {
 isSort("uhsnamiH");
 }

 private static void isSort(String name) {
 String revName="";
 for (int i = name.toCharArray().length-1; i &gt;0 ; i--) {
 revName=revName+name.charAt(i);
 }
 System.out.println(revName);
 }

}
</code></pre>

blocks|key|553814|text|在不使用数组的情况下，您可以存储字符并以相反的顺序连接它们。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|553815|public+static+String+reverseString(String+inpt)+{

++++String+sb+=+"";
++++for(int+i+=+inpt.length()-1;+i>=0;+i--)+{

++++++++sb+=+sb.concat(""%2Binpt.charAt(i));
++++}

++++return+sb;
}|code-block|syntax|javascript|553816|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Without Using Arrays, you can store the Characters and concatenate them in reverse order.

<pre><code>public static String reverseString(String inpt) {

 String sb = "";
 for(int i = inpt.length()-1; i&gt;=0; i--) {

 sb = sb.concat(""+inpt.charAt(i));
 }

 return sb;
}
</code></pre>

blocks|key|553930|text|下面是可用于反转字符串的代码。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|553931|public+static+void+main(String[]+args)+{

++++++++String+aString+=+"noun";

++++++++int+size+=+aString.length();
++++++++String+reversed+=+"";

++++++++for+(int+i=size-1;i>=0;i--){
++++++++++++reversed+=+reversed%2B+aString.charAt(i);
++++++++++++if+(i+==+0)
++++++++++++++++System.out.println(reversed);
++++++++}
}|code-block|syntax|javascript|553932|您还可以观看视频以更好地理解https://www.youtube.com/watch?v=KaoA0o2Tfi4所需的概念|offset|length|553933|entityMap|0|LINK|mutability|MUTABLE|url|https://www.youtube.com/watch?v=KaoA0o2Tfi4^0|0|0|E|17|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

Here is the code that can be used to reverse a String.

<pre><code>public static void main(String[] args) {

 String aString = "noun";

 int size = aString.length();
 String reversed = "";

 for (int i=size-1;i&gt;=0;i--){
 reversed = reversed+ aString.charAt(i);
 if (i == 0)
 System.out.println(reversed);
 }
}
</code></pre>

you can also watch the video to better understand the concepts that are needed 
<a href="https://www.youtube.com/watch?v=KaoA0o2Tfi4" rel="nofollow noreferrer">https://www.youtube.com/watch?v=KaoA0o2Tfi4</a>

blocks|key|553983|text|您也可以使用for语句：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|553984|++++++for+(int+y+=+0;+y+<+phrase.length();+y--){
++++++char+ch+=+phrase.charAt(y-1);
++++++System.out.print(ch);
++++++}|code-block|syntax|javascript|553985|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can use a for statement too:

<pre><code> for (int y = 0; y &lt; phrase.length(); y--){
 char ch = phrase.charAt(y-1);
 System.out.print(ch);
 }
</code></pre>

blocks|key|554026|text|只是另一种方法|type|unstyled|depth|inlineStyleRanges|entityRanges|data|554027|private+void+revByFor()+{
++++++++++++String+str="google";
++++++++++++StringBuilder+revStr=+new+StringBuilder();
++++++++++++char[]+str1=+str.toCharArray();
++++++++++++for+(char+c+:+str1)+{
++++++++++++++++revStr.insert(0,+c);++++
++++++++++++}
++++++++++++System.out.println(revStr);+
++++++++}|code-block|syntax|javascript|554028|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Just another method
<pre><code>private void revByFor() {
 String str=&quot;google&quot;;
 StringBuilder revStr= new StringBuilder();
 char[] str1= str.toCharArray();
 for (char c : str1) {
 revStr.insert(0, c); 
 }
 System.out.println(revStr); 
 }
</code></pre>

blocks|key|770609|text|public+class+StringReverse1+{

public+static+void+main(String[]+args)+{
++++String+name+=+"Vaquar+khan";

++++char+array[]+=+name.toCharArray();
++++System.out.println(name);
++++System.out.println(reverseString(array));
}

private+static+String+reverseString(char[]+array)+{
++++String+reverse+=+"";
++++///
++++for+(int+i+=+array.length+-+1;+i+>=+0;+i--)+{
++++++++//System.out.println(array[i]);
++++++++//
++++++++reverse+%2B=+array[i];
++++}
++++return+reverse;

}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|770610|}|unstyled|770611|结果：|770612|++++++Vaquar+khan

++++++nahk+rauqaV|770613|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$B|C]]|$1|K|3|-4|5|F|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>public class StringReverse1 {

public static void main(String[] args) {
 String name = &quot;Vaquar khan&quot;;

 char array[] = name.toCharArray();
 System.out.println(name);
 System.out.println(reverseString(array));
}

private static String reverseString(char[] array) {
 String reverse = &quot;&quot;;
 ///
 for (int i = array.length - 1; i &gt;= 0; i--) {
 //System.out.println(array[i]);
 //
 reverse += array[i];
 }
 return reverse;

}
</code></pre>
}
Results :
<pre><code> Vaquar khan

 nahk rauqaV
</code></pre>

blocks|key|770663|text|您可以不使用StringBuilder编写，也可以使用StringBuilder编写，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|770664|private+static+boolean+isPalindrome(int+number){
++++boolean+isPalindrome+=+false;
++++String+original="",+reversed="";
++++original+=+String.valueOf(number);
++++++++for(int+y=original.length()+-1;+y+>=+0;+y--){
++++++++++++reversed+%2B=+original.charAt(y);
++++++++}
++++++++if(original.equals(reversed)){
++++++++++++isPalindrome=true;
++++++++}
++++++++return+isPalindrome;
}

private+static+boolean+isPalindrome(String+original){
++++boolean+isPalindrome+=+false;
++++StringBuilder+reversed=new+StringBuilder(original).reverse();
++++if(original.equals(reversed.toString())){
++++++++isPalindrome=true;
++++}
++++return+isPalindrome;
}|code-block|syntax|javascript|770665|第一个方法检查int的回文类型，另一个检查String的类型。|770666|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

you can write without StringBuilder or with StringBuilder as follows:
<pre><code>private static boolean isPalindrome(int number){
 boolean isPalindrome = false;
 String original=&quot;&quot;, reversed=&quot;&quot;;
 original = String.valueOf(number);
 for(int y=original.length() -1; y &gt;= 0; y--){
 reversed += original.charAt(y);
 }
 if(original.equals(reversed)){
 isPalindrome=true;
 }
 return isPalindrome;
}

private static boolean isPalindrome(String original){
 boolean isPalindrome = false;
 StringBuilder reversed=new StringBuilder(original).reverse();
 if(original.equals(reversed.toString())){
 isPalindrome=true;
 }
 return isPalindrome;
}
</code></pre>
first method checks for a palindrome for an int and the other for a String.

blocks|key|770694|text|fun+reverse(original:+String):+String+{
++++val+toReserve+=+String(original.toByteArray(Charset.forName("UTF-16")),+Charset.forName("UTF-16"))
++++return+StringBuilder(toReserve).reverse().toString()
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|770695|应该可以在Java/Kotlin中使用代理对。|unstyled|770696|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>fun reverse(original: String): String {
 val toReserve = String(original.toByteArray(Charset.forName(&quot;UTF-16&quot;)), Charset.forName(&quot;UTF-16&quot;))
 return StringBuilder(toReserve).reverse().toString()
}
</code></pre>
Should work in Java/Kotlin with surrogate pairs.

blocks|key|553091|text|import+java.util.Scanner;
public+class+StringReverseExample
{
++++public+static+void+main(String[]+args)
++++{
++++++++String+str,rev;
++++++++Scanner+in+=+new+Scanner(System.in);
++++++++System.out.print("Enter+the+string+:+");
++++++++str+=+in.nextLine();
++++++++rev+=+new+StringBuffer(str).reverse().toString();
++++++++System.out.println("\nString+before+reverse:"%2Bstr);
++++++++System.out.println("String+after+reverse:"%2Brev);
++++}
}
/*+Output+:+
Enter+the+string+:+satyam

String+before+reverse:satyam
String+after+reverse:maytas+*/|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|553092|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>import java.util.Scanner;
public class StringReverseExample
{
 public static void main(String[] args)
 {
 String str,rev;
 Scanner in = new Scanner(System.in);
 System.out.print("Enter the string : ");
 str = in.nextLine();
 rev = new StringBuffer(str).reverse().toString();
 System.out.println("\nString before reverse:"+str);
 System.out.println("String after reverse:"+rev);
 }
}
/* Output : 
Enter the string : satyam

String before reverse:satyam
String after reverse:maytas */
</code></pre>

blocks|key|770346|text|也许使用new+StringBuilder(str).reverse.toString()已经足够方便和高效了。但是如果你想自己做，试试这个：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|770347|public+static+String+reverse(String+str)+{
++++StringBuilder+sb+=+new+StringBuilder(str.length());
++++for+(int+i+=+str.length()+-+1;+i+>=+0;+i--)+{
++++++++sb.append(str.charAt(i));
++++}
++++return+sb.toString();
}|code-block|syntax|javascript|770348|一些答案使用str.toCharArray()来获取这个字符串的字符数组，这将导致分配新的内存来存储这些字符，这是低效的。|770349|StringBuffer是线程安全的，但StringBuilder不是。所以StringBuffer的效率比StringBuilder低。如果没有必要，使用StringBuilder是一种更好的做法。|770350|entityMap^0|4|15|0|0|6|H|0|0|C|K|D|12|C|1I|D|26|D|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|X|8|@$9|Y|A|Z|B|C]|$9|10|A|11|B|C]|$9|12|A|13|B|C]|$9|14|A|15|B|C]|$9|16|A|17|B|C]]|D|@]|E|$]]|$1|O|3|-4|5|6|7|18|8|@]|D|@]|E|$]]]|P|$]]

Maybe using <code>new StringBuilder(str).reverse.toString()</code> is convenient and efficient enough. But if you wanna do it yourself, try this one:

<pre><code>public static String reverse(String str) {
 StringBuilder sb = new StringBuilder(str.length());
 for (int i = str.length() - 1; i &gt;= 0; i--) {
 sb.append(str.charAt(i));
 }
 return sb.toString();
}
</code></pre>

Some answers use <code>str.toCharArray()</code> to get this string's char array, this will result to allocate new memory to store these chars, which is not efficient. 

<code>StringBuffer</code> is thread safe, but <code>StringBuilder</code> is not. So <code>StringBuffer</code> is less efficient than <code>StringBuilder</code>. If not necessary, use <code>StringBuilder</code> is a better practice.

I have <code>"Hello World"</code> kept in a String variable named <code>hi</code>.

I need to print it, but reversed.

How can I do this? I understand there is some kind of a function already built-in into Java that does that.

Related: <a href="https://stackoverflow.com/questions/2441501/reverse-hello-world-in-java">Reverse each individual word of “Hello World” string with Java</a>

Reverse a string in Java

我将"Hello World"保存在一个名为hi的字符串变量中。我需要把它打印出来，但被颠倒了。我该怎么做呢？据我所知，Java中已经内置了某种函数可以做到这一点。相关：

问在Java中反转字符串
EN

回答 39

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问在Java中反转字符串EN

回答 39

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问在Java中反转字符串
EN