差異處
這裏顯示兩個版本的差異處。
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java:code_quality:findbug:dm_nextint_via_nextdouble [2013/02/24 23:01] 127.0.0.1 外部編輯 |
java:code_quality:findbug:dm_nextint_via_nextdouble [2023/06/25 09:48] |
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| - | {{tag>java findbugs}} | ||
| - | ====== DM_NEXTINT_VIA_NEXTDOUBLE ====== | ||
| - | ===== Description ===== | ||
| - | Dm: Method uses the nextDouble method of Random to generate a random integer; using nextInt is more efficient\\ | ||
| - | 使用nextDouble去產生一個random integer，造成效能降低。 | ||
| - | ===== Solution ===== | ||
| - | If r is a java.util.Random, you can generate a random number from 0 to n-1 using r.nextInt(n), rather than using (int)(r.nextDouble() * n). \\ | ||
| - | 用nextInt(n)取代(int)(r.nextDouble() * n)即可。 | ||
| - | ===== Example ===== | ||
| - | Before:\\ | ||
| - | <code java> | ||
| - | private static void delay(){ | ||
| - | int d = (int)(Math.random()*1000); | ||
| - | try { | ||
| - | Thread.sleep(d); | ||
| - | } catch (InterruptedException e) { | ||
| - | // log.. | ||
| - | } | ||
| - | } | ||
| - | </code> | ||
| - | After:\\ | ||
| - | <code java> | ||
| - | private static void delay(){ | ||
| - | int d = r.nextInt(1000); | ||
| - | try { | ||
| - | Thread.sleep(d); | ||
| - | } catch (InterruptedException e) { | ||
| - | // log.. | ||
| - | } | ||
| - | } | ||
| - | </code> | ||
| - | |||
| - | PS. Math.random()內也是會去產生Random物件去取得亂數值。 | ||
