//創建一個分發器
RandomDispatcher randomDispatcher = new RandomDispatcher();

//設置每種事件的概率，注意，概率之和不一定是100哦
randomDispatcher.put(20, 1);
randomDispatcher.put(1, 2);
randomDispatcher.put(29, 3);
randomDispatcher.put(50, 4);

//隨機
int retIndex = randomDispatcher.random();

//根據隨機結果去執行不同的方法
switch (retIndex) {
case 1:
 System.out.println("do method A");
 break;
case 2:
 System.out.println("do method B");
 break;
case 3:
 System.out.println("do method C");
 break;
case 4:
 System.out.println("do method D");
 break;

default:
 break;
}