Java-多线程-Thread类-继承方式

1、常规的单线程

package cn.bruce.Thread;

//如何创建和启动一个线程
//创建Thread子类对象
//子类对象调用方法start()
//让线程程序执行，JVM调用线程中的run
public class MoreThreadDemo {
    public static void main(String[] args) {
        long ss = System.currentTimeMillis();
        SubThread st = new SubThread();
        st.run();// 如果是直接调用run的话还是单线程
        // st.start();
　　　　new Thread(){public void run(){System.out.println("!!!");}}.start();//也可以使用这样的匿名内部类方式开启线程

        long s = System.currentTimeMillis();
        long r = fun(45);
        long e = System.currentTimeMillis();
        System.out.println("main..." + (e - s));
        System.out.println(r);
        long ee = System.currentTimeMillis();
        System.out.println("result..." + (ee - ss));
    }

    public static long fun(long a) {
        if (a == 1)
        {
            return 1;
        } else if (a == 2)
        {
            return 1;
        }
        return fun(a - 2) + fun(a - 1);
    }

}

// 定义子类，继承Thread
// 重写方法run
class SubThread extends Thread {
    public void run() {
        long s1 = System.currentTimeMillis();
        long r1 = fun1(45);
        long e1 = System.currentTimeMillis();
        System.out.println("run..." + (e1 - s1));
        System.out.println(r1);
    }

    public static long fun1(long a) {
        if (a == 1)
        {
            return 1;
        } else if (a == 2)
        {
            return 1;
        }
        return fun1(a - 2) + fun1(a - 1);
    }
}

 

 需要6874ms

2、开辟一个线程后

package cn.bruce.Thread;

//如何创建和启动一个线程
//创建Thread子类对象
//子类对象调用方法start()
//让线程程序执行，JVM调用线程中的run
public class MoreThreadDemo {
    public static void main(String[] args) {
        long ss = System.currentTimeMillis();
        SubThread st = new SubThread();
        // st.run();// 如果是直接调用run的话还是单线程
        st.start();//开辟线程运行
        long s = System.currentTimeMillis();
        long r = fun(45);
        long e = System.currentTimeMillis();
        System.out.println("main..." + (e - s));
        System.out.println(r);
        long ee = System.currentTimeMillis();
        System.out.println("result..." + (ee - ss));
    }

    public static long fun(long a) {
        if (a == 1)
        {
            return 1;
        } else if (a == 2)
        {
            return 1;
        }
        return fun(a - 2) + fun(a - 1);
    }

}

// 定义子类，继承Thread
// 重写方法run
class SubThread extends Thread {
    public void run() {
        long s1 = System.currentTimeMillis();
        long r1 = fun1(45);
        long e1 = System.currentTimeMillis();
        System.out.println("run..." + (e1 - s1));
        System.out.println(r1);
    }

    public static long fun1(long a) {
        if (a == 1)
        {
            return 1;
        } else if (a == 2)
        {
            return 1;
        }
        return fun1(a - 2) + fun1(a - 1);
    }
}

 

 只需要4042ms了