java 赛马机。完成赛马的设计，必须实现几个基本功能：1.马匹获得随机速度，在规定的长度内，完成赛马比赛；2.设计一组单选按钮，供用户选择胜出马匹；3.用户可以为自己的马匹投注；4.用户可以增加自己投注的总金额。-java horse racing machine. To complete the design in horse racing, must implement a few basic functions: horses get random speed within the specified length, complete horse racing　design a set of radio buttons for the user to select the winning horses　3 users can horses betting　4 users can increase the total amount of their bets.