学步园

package concurrent;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.FutureTask;

//用十个线程计算一个数组的和
class TaskWithResult implements Callable<Integer> {
	private Integer[] ints;

	public TaskWithResult(Integer[] ints) {
		this.ints = ints;
	}

	private int sumFromArray() {
		int result = 0;
		for (int a : this.ints) {
			result += a;
		}
		return result;
	}

	@Override
	public Integer call() throws Exception {
		return sumFromArray();
	}
}

public class Paiallel1 {
	public static Integer[] segArray(int start, int end, int[] array) {
		List<Integer> result = new ArrayList<Integer>();
		for (int i = start; i < end; i++) {
			result.add(array[i]);
		}

		Integer[] ary = result.toArray(new Integer[result.size()]);

		return ary;
	}

	public static int getSum(int[] array) {
		int result = 0;
		for (int i = 0; i < array.length; i++) {
			result += array[i];
		}
		return result;
	}

	public static void main(String[] args) throws InterruptedException,
			ExecutionException {
		long start1 = System.currentTimeMillis();
		ExecutorService exec = Executors.newFixedThreadPool(10);
		int[] array = { 300, 800, 89, 390, 892, 9384, 909, 1, 343, 5839, 939,
				43, 355, 323, 32, 55, 3, 3, 43, 5, 5, 45, 555, 554, 554, 555,
				545, 555, 553, 35, 2322, 332, 3232, 433, 344, 524, 245, 524,
				6565, 526 };

		List<FutureTask<Integer>> tasks = new ArrayList<FutureTask<Integer>>();

		for (int i = 0; i < 10; i++) {
			int incre = array.length / 10;
			int start = i * incre;
			int end = (i + 1) * incre;
			if (end > array.length)
				end = array.length;
			Integer[] prt = segArray(start, end, array);

			TaskWithResult calbTask = new TaskWithResult(prt);
			FutureTask<Integer> task = new FutureTask<Integer>(calbTask);
			tasks.add(task);
			if (!exec.isShutdown()) {
				exec.submit(task);
			}
		}

		int result = 0;
		for (FutureTask<Integer> task : tasks) {
			int partRst = task.get();
			result += partRst;
		}
		exec.shutdown();
		long end1 = System.currentTimeMillis();
		System.out.println("并行计算耗时：" + (end1 - start1));
		System.out.println("并行计算的结果：" + result);
		
		long start2 = System.currentTimeMillis();
		int result2 = getSum(array);
		long end2 = System.currentTimeMillis();
		
		System.out.println("并行计算耗时：" + (end2 - start2));
		System.out.println("单独计算的结果：" + result2);

	}

}

　　

package concurrent;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

//用十个线程计算一个数组的和
class TaskWithResult1 implements Callable<Integer> {
	private Integer[] ints;

	public TaskWithResult1(Integer[] ints) {
		this.ints = ints;
	}

	private int sumFromArray() {
		int result = 0;
		for (int a : this.ints) {
			result += a;
		}
		return result;
	}

	@Override
	public Integer call() throws Exception {
		return sumFromArray();
	}
}

public class Paiallel2 {
	public static Integer[] segArray(int start, int end, int[] array) {
		List<Integer> result = new ArrayList<Integer>();
		for (int i = start; i < end; i++) {
			result.add(array[i]);
		}

		Integer[] ary = result.toArray(new Integer[result.size()]);

		return ary;
	}

	public static int getSum(int[] array) {
		int result = 0;
		for (int i = 0; i < array.length; i++) {
			result += array[i];
		}
		return result;
	}

	public static void main(String[] args) throws InterruptedException,
			ExecutionException {
		ExecutorService exec = Executors.newFixedThreadPool(10);
		CompletionService<Integer> cplSvc = new ExecutorCompletionService<Integer>(
				exec);

		int[] array = { 300, 800, 89, 390, 892, 9384, 909, 1, 343, 5839, 939,
				43, 355, 323, 32, 55, 3, 3, 43, 5, 5, 45, 555, 554, 554, 555,
				545, 555, 553, 35, 2322, 332, 3232, 433, 344, 524, 245, 524,
				6565, 526 };

		for (int i = 0; i < 10; i++) {
			int incre = array.length / 10;
			int start = i * incre;
			int end = (i + 1) * incre;
			if (end > array.length)
				end = array.length;
			Integer[] prt = segArray(start, end, array);

			TaskWithResult1 calbTask = new TaskWithResult1(prt);
			if (!exec.isShutdown()) {
				cplSvc.submit(calbTask);
			}
		}

		int result = 0;
		for (int i = 0; i < 10; i++) {
			int partRst = cplSvc.take().get();
			result += partRst;
		}
		exec.shutdown();
		System.out.println("并行计算的结果：" + result);

		int result2 = getSum(array);
		System.out.println("单独计算的结果：" + result2);

	}

}