import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Random;
public class zifuchuan {
private List<String>string;
//StringBuilder sb = new StringBuilder() ;
//Random random = new Random();不能在此处定义sb和random;
String k;
public zifuchuan(){
this.string = new ArrayList<String>();
}
/**

• 利用charAt（）方法来实现在st这个长字符串中选取合适长度的和合适的字母组成随机的字符串；
• 利用循环；
  *利用apend函数进行字符串的插入;
• 因为charAt方法在括号中要加入索引位置，故在其方法括号中利用随机数来进行选择；

• @return
  */
  public String creat(){
  StringBuilder sb = new StringBuilder() ;
  Random random = new Random();
  String st = "01234ABCmopqDEFGnKNO579PQRSTUVW6XYZabcdHIJefghijklrstLMwx8yz";
  int sr = random.nextInt(10)+1;
  for(int i = 0;i < sr;i++){
  sb.append( st.charAt(random.nextInt(st.length())));
  }
  return sb.toString();
  }
  public void test(){
  for(int j = 0;j<10;j++){
  do{
  k = creat();
  }while(string.contains(k));
  string.add(k); //*此处利用函数调用**
  }
  }
  public void foreach(){
  System.out.println("---------------排序前---------");
  for (String string2 : string) {
  System.out.println(string2);
  }
  }
  public void testforeach(){
  System.out.println("---------------排序后---------");
  Collections.sort(string);
  for (String string2 : string) {
  System.out.println(string2);
  }
  }
  @Override
  public boolean equals(Object obj) {
  if (this == obj)
  return true;
  if (obj == null)
  return false;
  if (getClass() != obj.getClass())
  return false;
  zifuchuan other = (zifuchuan) obj;
  if (k == null) {
  if (other.k != null)
  return false;
  } else if (!k.equals(other.k))
  return false;
  return true;
  }

  public static void main(String []args){
  zifuchuan zf = new zifuchuan();

  zf.test();
  zf.foreach();
  zf.testforeach();

  }

}