多线程查找

1.本算法采用的是将多线程查找实现方法：将大批量数据切割分成多份，让线程去寻找，如果找到了，则返回数据

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1	DavideSearch

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package cn.lonecloud.search;   import java.util.LinkedList; import java.util.List; import java.util.concurrent.*; import java.util.concurrent.atomic.AtomicInteger;   /**  * @author lonecloud  * @version v1.0  * @date 下午3:37 2018/5/9  */ public class DavideSearch<T> {       private T[] data;       private int divCount;       private AtomicInteger index;       public DavideSearch(T[] data, int divCount) {         this.data = data;         this.divCount = divCount;         index = new AtomicInteger(-1);     }       static ExecutorService service = new ThreadPoolExecutor(0, 10, 60, TimeUnit.SECONDS, new SynchronousQueue<>(), new ThreadFactory() {         AtomicInteger integer = new AtomicInteger();           @Override         public Thread newThread(Runnable r) {             return new Thread(r, "search-thread" + integer);         }     });       public <T> int divSearch(T searchValue) {         int subSize = data.length / divCount;         for (int i = 0; i < data.length; i += subSize) {             int end = i + subSize;             if (end > data.length) {                 end = data.length;             }             SearchTask<T> searchTask = new SearchTask<>(i, end, searchValue, (T[]) data, index);             Future<Integer> submit = service.submit(searchTask);         }         return index.get();     } }

 SearchTask

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package cn.lonecloud.search;   import java.util.Objects; import java.util.concurrent.Callable; import java.util.concurrent.atomic.AtomicInteger;   /**  * @author lonecloud  * @version v1.0  * @date 上午9:52 2018/5/9  */ public class SearchTask<T> implements Callable<Integer> {     private int begin, end;     private T searchValue;     private T[] data;     private AtomicInteger result;       public SearchTask(int begin, int end, T searchValue, T[] data, AtomicInteger index) {         this.begin = begin;         this.end = end;         this.searchValue = searchValue;         this.data = data;         this.result = index;     }       @Override     public Integer call() throws Exception {         return search(searchValue, begin, end);     }       private int search(T searchValue, int begin, int end) {         int i = 0;         for (i = begin; i < end; i++) {             if (data[i].equals(searchValue)) {                 //并发如果其他线程先找到                 if (!result.compareAndSet(-1, i)) {                     return result.get();                 }                 return i;             }         }         return -1;     } }

测试类

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package cn.lonecloud;   import cn.lonecloud.search.DavideSearch; import org.junit.jupiter.api.Test;   import java.util.Random; import java.util.UUID;   /**  * @author lonecloud  * @version v1.0  * @date 下午3:52 2018/5/9  */ public class MainTest {       static final int MAX=100000;     @Test     public void integerTest() {         Integer[] arr = new Integer[MAX];         Random random = new Random();         int index = random.nextInt(MAX);         for (int i = 0; i < MAX; i++) {             arr[i] = random.nextInt(MAX);         }         DavideSearch<Integer> davideSearch = new DavideSearch<>(arr, 3);         int i = davideSearch.divSearch(arr[index]);         System.out.print(index + "-------->" + i);     }       @Test     public void StringTest() {         long start = System.currentTimeMillis();         String[] arr = new String[MAX];         Random random = new Random();         int index = random.nextInt(MAX);         for (int i = 0; i < MAX; i++) {             arr[i] = UUID.randomUUID().toString();         }         DavideSearch<String> davideSearch = new DavideSearch<>(arr, 3);         int i = davideSearch.divSearch(arr[index]);         System.out.println(index + "-------->" + i);         System.out.println("end"+(System.currentTimeMillis()-start));     }     @Test     public void NoramlSearch() {         long start = System.currentTimeMillis();         String[] arr = new String[MAX];         Random random = new Random();         int index = random.nextInt(MAX);         for (int i = 0; i < MAX; i++) {             arr[i] = UUID.randomUUID().toString();         }         for (int i = 0; i < arr.length; i++) {             if (arr[i].equals(arr[index])){                 System.out.println(index + "-------->" + i);             }         }         System.out.println("end"+(System.currentTimeMillis()-start));     } }