问题链接及题解：向老师学习，努力努力再努力！ 问题源链接
题意简述： 输入一英文文段，从中提取出单词，要求重复的单词被去掉，大写单词全部转化为小写，并且按照字母表的顺序打印输出 Sample Input
Adventures in Disneyland.Two blondes were going to Disneyland when they came to a fork in theroad. The sign read: "Disneyland Left.".So they went home.Sample output
a adventures blondes came disneyland fork going home in left read sign so the theroad they to two went were when思路分析： 1.我们从键盘上输入一英文段Scanner.nextLine()包括英文符号，字母和空格都要读入 2.我们要对其进行处理，先将其转为字符数组对数组中的每一个字符判断其是否为字母，如果不是就将其转为空格作为分隔符来切割单词串 3.再将处理好的字符数组转为String的字符串（此时的字符串只有单词和空格两种形式，没有其他的字符了） 4.我们用spilit()函数来利用空格作为分隔符切割字符，后使用TreeSet 结构来存储每个切割的字符串并且转为小写 这里用TreeSet非常重要，因为这个存储的数据结构有很强的优势，一：元素不会重复，为我们省去了去重的时间，二：TreeSet 中的元素会按照自然顺序排好序，让我们能够很好的依次按序输出 5.最后遍历这个TreeSet 我们的结果就出来了
package Exercises; import java.util.*; public class TheSplitOfString { public static void main(String[] args) { Scanner s=new Scanner(System.in); String str1; str1=s.nextLine(); char[] array=str1.toCharArray(); for (int i = 0; i < array.length; i++) { if(!Character.isLetter(array[i])) array[i]=' '; } String str2=new String(array); Set<String> set=new TreeSet<String>(); String[] string=str2.split(" "); for (String s1:string) { set.add(s1.toLowerCase()); } for (String s2:set) { System.out.print(s2+" "); } } }结果测试：
//输入如下 Adventures in Disneyland。Two blondes were going to Disneyland when they came to a fork in theroad. The sign read: "Disneyland Left."。So they went home. //输出如下 a adventures blondes came disneyland fork going home in left read sign so the theroad they to two went were when Process finished with exit code 0成功！！ Java，我爱的语言，让我们一起学习，一起努力吧！！
