去掉字符串中重复的字符

package my;
public class number {
    public static void main(String[] args) {
        String s="白日依山尽，黄河入海流。欲穷千里目，更上一层楼。";
        StringBuilder sb = new StringBuilder(s);
        System.out.println("原来的字符串是："+sb);
        System.out.println("原来的字符串长度是：" + sb.length());
        for (int i=0;i 
  
效果如下：