HeadFirstJava学习心得——main方法

• 测试真正的类
• 启动java application

下面的一个猜数字的游戏充分体现了以上观点：

public class Player {
	int number = 0; // 被猜测的数字

	public void guess() {
		number = (int) (Math.random() * 10);
		System.out.println("I'm guessing " + number);
	}
}

猜数字游戏类：游戏的内部逻辑

public class GuessGame {
	/* 用3个实例变量分别表示3个Player对象 */
	Player p1;
	Player p2;
	Player p3;

	public void startGame() {
		/* 创建3个Player对象 */
		p1 = new Player();
		p2 = new Player();
		p3 = new Player();

		/* 声明3个变量来保存猜测的数字 */
		int guessp1 = 0;
		int guessp2 = 0;
		int guessp3 = 0;

		/* 声明3个变量来保存是否猜中 */
		boolean p1isRight = false;
		boolean p2isRight = false;
		boolean p3isRight = false;

		/* 产生谜底数字 */
		int targetNumber = (int) (Math.random() * 10);
		System.out.println("I'm thinking of a number between 0 and 9...");

		while (true) {
			System.out.println("Number to guess is " + targetNumber);

			/* 调用Player的guess（）方法 */
			p1.guess();
			p2.guess();
			p3.guess();

			/* 取得每个Player所猜测的数字并将其列出 */
			guessp1 = p1.number;
			System.out.println("Player one guessed " + guessp1);
			guessp2 = p2.number;
			System.out.println("Player two guessed " + guessp2);
			guessp3 = p3.number;
			System.out.println("Player three guessed " + guessp3);

			/* 检查是否猜中，若猜中则设定是否猜中的变量 */
			if (guessp1 == targetNumber) {
				p1isRight = true;
			}
			if (guessp2 == targetNumber) {
				p2isRight = true;
			}
			if (guessp3 == targetNumber) {
				p3isRight = true;
			}

			/* 如果有人猜中，就打印信息，结束游戏 */
			if (p1isRight || p2isRight || p3isRight) {
				System.out.println("We have a winner!");
				System.out.println("Player one got it right?" + p1isRight);
				System.out.println("Player two got it right?" + p2isRight);
				System.out.println("Player three got it right?" + p3isRight);
				System.out.println("Game over.");
				break;
			} else {
				// 都没有猜到，所以要继续下去
				System.out.println("Player will have to try it agin.");
			}
		}
	}
}

主方法：启动游戏

public class GameLauncher {

	public static void main(String[] args) {
		GuessGame game = new GuessGame();
		game.startGame();
	}

}

游戏的运行结果：

I‘m thinking of a number between 0 and 9...
Number to guess is 6
I‘m guessing 9
I‘m guessing 9
I‘m guessing 2
Player one guessed 9
Player two guessed 9
Player three guessed 2
Player will have to try it agin.
Number to guess is 6
I‘m guessing 8
I‘m guessing 5
I‘m guessing 8
Player one guessed 8
Player two guessed 5
Player three guessed 8
Player will have to try it agin.
Number to guess is 6
I‘m guessing 3
I‘m guessing 8
I‘m guessing 8
Player one guessed 3
Player two guessed 8
Player three guessed 8
Player will have to try it agin.
Number to guess is 6
I‘m guessing 0
I‘m guessing 4
I‘m guessing 7
Player one guessed 0
Player two guessed 4
Player three guessed 7
Player will have to try it agin.
Number to guess is 6
I‘m guessing 5
I‘m guessing 3
I‘m guessing 5
Player one guessed 5
Player two guessed 3
Player three guessed 5
Player will have to try it agin.
Number to guess is 6
I‘m guessing 6
I‘m guessing 9
I‘m guessing 7
Player one guessed 6
Player two guessed 9
Player three guessed 7
We have a winner!
Player one got it right?true
Player two got it right?false
Player three got it right?false
Game over.

java的垃圾回收机制（GC）

需要全局变量（global）或者方法该如何？

成百上千的类应该如何提交？是否可以包装成类似单一应用程序的形式？