java 字符串反转

public class StringReverse {

public void swap(char[] arr, int begin, int end) {
while(begin < end) {　　　　　　
char temp = arr[begin];
arr[begin] = arr[end];
arr[end] = temp;
begin++;
end--;
}
}
//I love java
public String swapWords(String str) {
char[] arr = str.toCharArray();
swap(arr, 0, arr.length - 1);　　　　//第一次反转，结果为avaj evol I
int begin = 0;
for (int i = 1; i < arr.length; i++) {
if (arr[i] == ' ') {　　　　　　 //第二次和三次反转，结果分别为java evol I和java love I
swap(arr, begin, i - 1);　　　　
begin = i + 1;
}
}

return new String(arr);
}

public static void main(String[] args) {
String str = "I love java";
System.out.println(new StringReverse().swapWords(str));
}
}

public class fanzhuan {

public static void main(String[] args) {
String str = "I love java";
String[] sArr = str.split(" ");//I love java
List<String> list = new ArrayList<String>();
list = Arrays.asList(sArr);        　//此时list为[I,love,java]　
Collections.reverse(list);　　　　　　//reverse方法直接反转list的每个元素，反转后为[java,love,I]

for(String word:list){
System.out.print(word+" ");
}
}
}

package sundemo2;

public class fanzhuan {
public static void main(String[] args){
String str = "my name is 周杰伦";
System.out.println(reverse(str));

}
public static String reverse(String str){
return new StringBuilder(str).reverse().toString();
}
}

package sundemo2;

public class fanzhuan {
public static void main(String[] args){
String str = "my name is 周杰伦";

for(int i = str.length() - 1; i >= 0; i--){
System.out.print(str.charAt(i));
}
}
}