多线程并发快速处理数据

来源：互联网发布：视频后期制作软件ae 编辑：程序博客网时间：2024/05/20 06:53

方案一：

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.Future;public class LargSumWithCallable {static int threadCounts =10;//使用的线程数  static long sum=0;       public static void main(String []args) throws InterruptedException, ExecutionException{              ExecutorService exec=Executors.newFixedThreadPool(threadCounts);      List<Callable<Long>> callList=new ArrayList<Callable<Long>>();       List<Integer> list = new ArrayList<Integer>();        for (int j = 0; j <= 1000000;j++)  {          list.add(j);      }         int len=list.size()/threadCounts;//平均分割List      //List中的数量没有线程数多（很少存在）      if(len==0){          threadCounts=list.size();//采用一个线程处理List中的一个元素          len=list.size()/threadCounts;//重新平均分割List      }      for(int i=0;i<threadCounts;i++){          final List<Integer> subList;          if(i==threadCounts-1){              subList=list.subList(i*len,list.size());          }else{              subList=list.subList(i*len, len*(i+1)>list.size()?list.size():len*(i+1));          }          //采用匿名内部类实现          callList.add(new Callable<Long>(){              public Long call() throws Exception {                  long subSum=0L;                  for(Integer i:subList){                      subSum+=i;                  }                  System.out.println("分配给线程："+Thread.currentThread().getName()+"那一部分List的整数和为：\tSubSum:"+subSum);                  return subSum;              }          });      }      List<Future<Long>> futureList=exec.invokeAll(callList);      for(Future<Long> future:futureList){          sum+=future.get();      }      exec.shutdown();      System.out.println(sum);  } }

方案二：

import java.util.ArrayList;import java.util.List;import java.util.concurrent.BrokenBarrierException;import java.util.concurrent.CyclicBarrier;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;public class LargeListIntegerSum {     private long sum;//存放整数的和      private CyclicBarrier barrier;//障栅集合点(同步器)      private List<Integer> list;//整数集合List      private int threadCounts;//使用的线程数      public LargeListIntegerSum(List<Integer> list,int threadCounts) {          this.list=list;          this.threadCounts=threadCounts;      }      /**      * 获取List中所有整数的和      * @return      */      public long getIntegerSum(){          ExecutorService exec=Executors.newFixedThreadPool(threadCounts);          int len=list.size()/threadCounts;//平均分割List          //List中的数量没有线程数多（很少存在）          if(len==0){              threadCounts=list.size();//采用一个线程处理List中的一个元素              len=list.size()/threadCounts;//重新平均分割List          }          barrier=new CyclicBarrier(threadCounts+1);          for(int i=0;i<threadCounts;i++){              //创建线程任务              if(i==threadCounts-1){//最后一个线程承担剩下的所有元素的计算                  exec.execute(new SubIntegerSumTask(list.subList(i*len,list.size())));              }else{                  exec.execute(new SubIntegerSumTask(list.subList(i*len, len*(i+1)>list.size()?list.size():len*(i+1))));              }          }          try {              barrier.await();//关键，使该线程在障栅处等待，直到所有的线程都到达障栅处          } catch (InterruptedException e) {              System.out.println(Thread.currentThread().getName()+":Interrupted");          } catch (BrokenBarrierException e) {              System.out.println(Thread.currentThread().getName()+":BrokenBarrier");          }          exec.shutdown();          return sum;      }      /**      * 分割计算List整数和的线程任务           *      */      public class SubIntegerSumTask implements Runnable{          private List<Integer> subList;          public SubIntegerSumTask(List<Integer> subList) {              this.subList=subList;          }          public void run() {              long subSum=0L;              for (Integer i : subList) {                  subSum += i;              }                synchronized(LargeListIntegerSum.this){//在LargeListIntegerSum对象上同步                  sum+=subSum;              }              try {                  barrier.await();//关键，使该线程在障栅处等待，直到所有的线程都到达障栅处              } catch (InterruptedException e) {                  System.out.println(Thread.currentThread().getName()+":Interrupted");              } catch (BrokenBarrierException e) {                  System.out.println(Thread.currentThread().getName()+":BrokenBarrier");              }              System.out.println("分配给线程："+Thread.currentThread().getName()+"那一部分List的整数和为：\tSubSum:"+subSum);          }                }          public static void main(String[] args) {          List<Integer> list = new ArrayList<Integer>();          int threadCounts = 10;//采用的线程数                 for (int i = 1; i <= 1000000; i++) {              list.add(i);          }                  long start=  System.currentTimeMillis();        LargeListIntegerSum countListIntegerSum=new LargeListIntegerSum(list,threadCounts);               long sum=countListIntegerSum.getIntegerSum();              System.out.println("List中所有整数的和为:"+sum);         long end=  System.currentTimeMillis();             System.out.println(end-start);      }  }

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