Given an input string, reverse the string word by word.For example,Given s = "the sky is blue",return "blue is sky the".click to show clarification.Clarification:What constitutes a word?A sequence of non-space characters constitutes a word.Could the input string contain leading or trailing spaces?Yes. However, your reversed string should not contain leading or trailing spaces.How about multiple spaces between two words?Reduce them to a single space in the reversed string.

对于一个输入的字符串，逐个词反转这个字符串例如，所给的字符串s =  "the sky is blue",返回 "blue is sky the".说明： 每个词由什么组成？   由不含空格字符的序列组成每个词 输入的字符串的开头或者结尾能否包含空格？      是的，当然可以。但是在你反转的时候你应该把开头和结尾的字符空格去掉。如果两个词之间含有多个空格呢？ 在反转后的字符串中应该讲他们减少为一个空格。        

package ReverseWords;public class Solution {	    public String reverseWords(String s) {    	    	if(s == null||"".equals(s)){//判断是否为空，为空则直接返回    		return "";    	}    	StringBuffer strBuffer = new StringBuffer();    	String []tempArray = s.replaceAll("\\s{1,}", " ").split(" ");//去除多空格情况然后返回字符数组    	for(int index = tempArray.length-1;index >= 0;index--){    		strBuffer.append(tempArray[index]+" ");//拼接反转数组    	}    	return strBuffer.toString().trim();    }}

package ReverseWords;public class SolutionTest {	/**	 * @param args	 */	public static void main(String[] args) {		// TODO Auto-generated method stub		String str = "   a   b ";		System.out.println("反转后的字符串是:"+new Solution().reverseWords(str));	}}