字符串反转-java

/*

*将一个字符串反转：Hello world --> world Hello

*

*/

//对一个char数组进行整体反转

public static void subReverse(char[] str, Integer begin, Integer end) {
char temp;
while (begin <= end) {
temp = str[begin];
str[begin] = str[end];
str[end] = temp;
begin++;
end--;
}
}
public static void reverse(String str) {
// String str = "Hello World Welcome to china";

//构造每个分割的下标

List index = new ArrayList<Integer>();
char[] str1 = str.toCharArray();
index.add(-1);
for (int k = 0; k < str1.length; k++) {
if (str1[k] == ' ')
index.add(k);
}
index.add(str1.length);

//首先每个单词反转
for (int k = 0; k < index.size() - 1; k++) {
subReverse(str1, (Integer) index.get(k) + 1, (Integer) index
.get(k + 1) - 1);
}

//再对整体进行反转
subReverse(str1, 0, str1.length - 1);
for (int i = 0; i < str1.length; i++) {
System.out.print(str1[i]);
}
}