JAVA编程思想第四版-多线程的练习答案之练习3

package exercise.exercise04;

public class Fibonacci implements Runnable {

int fibonacciCount;

public Fibonacci(int fibonacciCount){
this.fibonacciCount = fibonacciCount;
}

@Override
public void run() {
System.out.print("Thread "+fibonacciCount+" :");

}

public int getFibonacci(int fibo){
if(fibo<2){
return 1;
}
return getFibonacci(fibo-1)+getFibonacci(fibo -2);
}
}
/** out put
* Thread 1:[0]
* Thread 2:[0,1]
* Thread 3:[0,1,1]
* Thread 4:[0,1,1,2]
* */

package exercise.exercise04;

public interface Generator<T> {
T next();
}

package exercise.exercise04;
import java.util.Arrays;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class MainFibonacci implements Runnable,Generator<Integer>{

int n;//n表示需要打印出来的fibonacci的个数
int count;//标记产生的Fibonacci的次数
public MainFibonacci(int n){

this.n = n;
System.out.println("exercise "+n);
}

public static void main(String[] args) throws InterruptedException {

System.out.println("***********************默认实现方式**************************");
//默认实现方式
for (int i = 1; i < 4; i++) {
new Thread(new MainFibonacci(i)).start();
}
Thread.sleep(2000);
System.out.println("***********************Cache实现方式**************************");
//CacheThreadPool实现方式
ExecutorService execCache = Executors.newCachedThreadPool();
for (int i = 1; i < 4; i++) {
execCache.execute(new MainFibonacci(i));
}
execCache.shutdown();
Thread.sleep(2000);
System.out.println("***********************Fixed实现方式**************************");
//FixedThreadPool实现方式
ExecutorService execFix = Executors.newFixedThreadPool(5);
for (int i =1; i < 4; i++) {
execFix.execute(new MainFibonacci(i));
}
execFix.shutdown();
Thread.sleep(2000);
System.out.println("***********************Single实现方式**************************");
//SingleThreadPool实现方式
ExecutorService execSingle = Executors.newSingleThreadExecutor();
for (int i = 1; i < 4; i++) {
execSingle.execute(new MainFibonacci(i));
}
execSingle.shutdown();
}

@Override
public Integer next() {
return getFibonacci(count++);
}

@Override
public void run() {
Integer[] sequence = new Integer
;
for (int i = 0; i < n; i++) {
sequence[i] = next();
}
System.out.println("sequence "+n+" : "+Arrays.toString(sequence));
}

public int getFibonacci(int fibo){
if(0==fibo){//第0个Fibonacci数为：0
return 0;
}
if(fibo<2){
return 1;
}
return getFibonacci(fibo-1)+getFibonacci(fibo -2);
}
}
/*
class Fibonacci implements Runnable {

int fibonacciCount;

public Fibonacci(int fibonacciCount){
this.fibonacciCount = fibonacciCount;
}

@Override
public void run() {
System.out.print("Thread "+fibonacciCount+" :");

}

public int getFibonacci(int fibo){
if(fibo<2){
return 1;
}
return getFibonacci(fibo-1)+getFibonacci(fibo -2);
}
}*/
/** out put
* Thread 1:[0]
* Thread 2:[0,1]
* Thread 3:[0,1,1]
* Thread 4:[0,1,1,2]
* */