Question

我想生成一个随机的唯一String并将其放入哈希表。我确实喜欢下面的代码，但它不是唯一的，而只是一个字符。

while(k<4){
    for(int j=1 ; j<=13 ;j++){
        Hashtable<Integer, String> Deck = new Hashtable();  
        int myChar = (int) (Math.random()*str.length());
        StringBuilder sb = new StringBuilder();
        sb.append(str.charAt(myChar)); 

        int i = (int) (Math.random() *52) ; 
        Deck.put(i, sb.toString());
        System.out.print(Deck);
    }

    System.out.println();
    k++;
}

输出是这个

{30=d}{9=e}{11=b}{10=d}{43=g}....

我想成为

{30=dea}{9=egt}{11=brf}{10=dgrtg}{43=grrh}{14=gwrt}.....

Answer 1

尝试使用以下代码通过随机方法生成唯一密钥。

WITH t AS (
      SELECT t.*, v.[Interval],
             AVG(v.[Interval]) OVER () as avg_interval
      FROM MyTable t CROSS JOIN
           (VALUES (DATEDIFF(minute, DateTimeCreated, DateTimeUpdated))
           ) v(Interval)
      WHERE DateTimeCreated > CAST(CAST(GETDATE() AS date) AS datetime)
     )
SELECT AVG(CASE WHEN t.[Interval] < t.avg_interval THEN t.[Interval] END) AS AverageEntryInterval,
       AVG(CASE WHEN t.[Interval] > t.avg_interval THEN t.[Interval] END) AS AverageExitInterval
FROM t;

Answer 2

您可以使用Apache Commons Lang生成字母字符串

String generatedString = RandomStringUtils.randomAlphanumeric(10);

尝试这样的事情

    Hashtable<Integer, String> Deck = new Hashtable();

    for (int i = 0; i < 10; i++) {
        String generatedString = RandomStringUtils.randomAlphanumeric(10);
        int key = (int) (Math.random() *52) ;
        Deck.put(key, generatedString);
    }
    System.out.println(Deck);

OutPut

{9=Ut7N87oMNp, 8=7kbARh5WIy, 7=pbU2ZCOGK1, 6=vAGAIw41Us, 5=VLnpY1FAuN, 4=UEIJNIvZlt, 3=z6Y3zXcDY1, 2=PxaMqXl8XW, 1=l72bkPdY6T, 0=FFdOsKpQgd}

如果只希望使用字母，请使用RandomStringUtils.randomAlphabetic(10);的{{1}}。

如果您不希望使用第三方api，则可以在代码段中进行一些更改

RandomStringUtils.randomAlphanumeric(10)

仅在while循环中添加了

Answer 3

您可以使用以下代码生成随机字符串。

private static final String ALPHA_STRING = "abcdefghijklmnopqrstuvwxyz";

public static String randomString(int count) {
    StringBuilder builder = new StringBuilder();
    while (count-- != 0) {
        int character = (int) (Math.random() * ALPHA_STRING.length());
        builder.append(ALPHA_STRING.charAt(character));
    }
    return builder.toString();
}

public static void main(String[] arg) {
    Hashtable<Integer, String> Deck = new Hashtable();
    for (int j = 1; j <= 10; j++) {
            Deck.put(j, randomString(12));
    }
    System.out.println(Deck);


}

输出

{10=upjolkfihcyh, 9=irpbrcoclcmx, 8=ppugclscjlja, 7=wtnvkpmocuwd, 6=gpyzppvywazp, 5=vosixtjvcqlg, 4=plwtzzjpzeoq, 3=wsdyyppphhng, 2=knqdzfctfnez, 1=jzakqfiksrho}

如何生成随机字符串并将其放入HashTable中？

3 个答案: