1. 類 Executors
此類中提供的一些方法有：
1.1 public static ExecutorService newCachedThreadPool ()
創建一個可根據需要創建新線程的線程池，但是在以前構造的 線程可用時將重用它們。對於執行很多短期異步任務的程序而言， 這些線程池通常可提高程序性能。
1.2 public static ExecutorService newFixedThreadPool (intnThreads)
創建一個可重用固定線程數的線程池，以共享的無界隊列方式 來運行這些線程。
1.3 public static ExecutorService newSingleThreadExecutor()
創建一個使用單個 worker 線程的 Executor，以無界隊列方式 來運行該線程。
這三個方法都可以配合接口ThreadFactory的實例一起使用。並 且返回一個ExecutorService接口的實例。
2. 接口 ThreadFactory
根據需要創建新線程的對象。使用線程工廠就無需再手工編寫 對 new Thread 的調用了，從而允許應用程序使用特殊的線程子類 、屬性等等。
此接口最簡單的實現就是：
class SimpleThreadFactory implements ThreadFactory {
public Thread newThread(Runnable r) {
return new Thread(r);
}
}
3. 接口ExecutorService
該接口提供了管理終止的方法。
4.創建標准線程池啟動線程
4.1 提供一個簡單的實現Runnable接口的線程
MyThread.java
package com.zj.concurrency.executors;
public class MyThread implements Runnable {
private int count = 1, number;
public MyThread(int num) {
number = num;
System.out.println("Create Thread-" + number);
}
public void run() {
while (true) {
System.out.println("Thread-" + number + " run " + count+" time(s)");
if (++count == 3)
return;
}
}
}
這個線程會打印出相應的創建和執行信息。
4.2 使用CachedThreadPool啟動線程
CachedThreadPool.java
package com.zj.concurrency.executors;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class CachedThreadPool {
public static void main(String[] args) {
ExecutorService exec = Executors.newCachedThreadPool();
for (int i = 0; i < 5; i++)
exec.execute(new MyThread(i));
exec.shutdown();
}
}
結果：
Create Thread-0
Create Thread-1
Create Thread-2
Create Thread-3
Thread-0 run 1 time(s)
Thread-0 run 2 time(s)
Thread-1 run 1 time(s)
Thread-1 run 2 time(s)
Thread-2 run 1 time(s)
Thread-2 run 2 time(s)
Create Thread-4
Thread-4 run 1 time(s)
Thread-4 run 2 time(s)
Thread-3 run 1 time(s)
Thread-3 run 2 time(s)
4.3 使用FixedThreadPool啟動線程
FixedThreadPool.java
package com.zj.concurrency.executors;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class FixedThreadPool {
public static void main(String[] args) {
ExecutorService exec = Executors.newFixedThreadPool(2);
for (int i = 0; i < 5; i++)
exec.execute(new MyThread(i));
exec.shutdown();
}
}
結果：
Create Thread-0
Create Thread-1
Create Thread-2
Create Thread-3
Create Thread-4
Thread-0 run 1 time(s)
Thread-0 run 2 time(s)
Thread-2 run 1 time(s)
Thread-2 run 2 time(s)
Thread-3 run 1 time(s)
Thread-3 run 2 time(s)
Thread-4 run 1 time(s)
Thread-4 run 2 time(s)
Thread-1 run 1 time(s)
Thread-1 run 2 time(s)
4.4 使用SingleThreadExecutor啟動線程
SingleThreadExecutor.java
package com.zj.concurrency.executors;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class SingleThreadExecutor {
public static void main(String[] args) {
ExecutorService exec = Executors.newSingleThreadExecutor();
for (int i = 0; i < 5; i++)
exec.execute(new MyThread(i));
exec.shutdown();
}
}
結果：
Create Thread-0
Create Thread-1
Create Thread-2
Create Thread-3
Create Thread-4
Thread-0 run 1 time(s)
Thread-0 run 2 time(s)
Thread-1 run 1 time(s)
Thread-1 run 2 time(s)
Thread-2 run 1 time(s)
Thread-2 run 2 time(s)
Thread-3 run 1 time(s)
Thread-3 run 2 time(s)
Thread-4 run 1 time(s)
Thread-4 run 2 time(s)
5.配合ThreadFactory接口的使用
我們試圖給線程加入daemon和priority的屬性設置。
5.1設置後台線程屬性
DaemonThreadFactory.java
package com.zj.concurrency.executors.factory;
import java.util.concurrent.ThreadFactory;
public class DaemonThreadFactory implements ThreadFactory {
public Thread newThread(Runnable r) {
Thread t = new Thread(r);
t.setDaemon(true);
return t;
}
}
5.2 設置優先級屬性
最高優先級MaxPriorityThreadFactory.java
package com.zj.concurrency.executors.factory;
import java.util.concurrent.ThreadFactory;
public class MaxPriorityThreadFactory implements ThreadFactory {
public Thread newThread(Runnable r) {
Thread t = new Thread(r);
t.setPriority(Thread.MAX_PRIORITY);
return t;
}
}
最低優先級MinPriorityThreadFactory.java
package com.zj.concurrency.executors.factory;
import java.util.concurrent.ThreadFactory;
public class MinPriorityThreadFactory implements ThreadFactory {
public Thread newThread(Runnable r) {
Thread t = new Thread(r);
t.setPriority(Thread.MIN_PRIORITY);
return t;
}
}
5.3啟動帶有屬性設置的線程
ExecFromFactory.java
package com.zj.concurrency.executors;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import com.zj.concurrency.executors.factory.DaemonThreadFactory;< BR> import com.zj.concurrency.executors.factory.MaxPriorityThreadFact ory;
import com.zj.concurrency.executors.factory.MinPriorityThreadFact ory;
public class ExecFromFactory {
public static void main(String[] args) throws Exception {
ExecutorService defaultExec = Executors.newCachedThreadPool();
ExecutorService daemonExec = Executors
.newCachedThreadPool(new DaemonThreadFactory());
ExecutorService maxPriorityExec = Executors
.newCachedThreadPool(new MaxPriorityThreadFactory());
ExecutorService minPriorityExec = Executors
.newCachedThreadPool(new MinPriorityThreadFactory());
for (int i = 0; i < 10; i++)
daemonExec.execute(new MyThread(i));
for (int i = 10; i < 20; i++)
if (i == 10)
maxPriorityExec.execute(new MyThread (i));
else if (i == 11)
minPriorityExec.execute(new MyThread (i));
else
defaultExec.execute(new MyThread(i));
}
}
結果：
Create Thread-0
Create Thread-1
Create Thread-2
Create Thread-3
Thread-0 run 1 time(s)
Thread-0 run 2 time(s)
Thread-1 run 1 time(s)
Thread-1 run 2 time(s)
Thread-2 run 1 time(s)
Thread-2 run 2 time(s)
Create Thread-4
Thread-4 run 1 time(s)
Thread-4 run 2 time(s)
Create Thread-5
Thread-5 run 1 time(s)
Thread-5 run 2 time(s)
Create Thread-6
Create Thread-7
Thread-7 run 1 time(s)
Thread-7 run 2 time(s)
Create Thread-8
Thread-8 run 1 time(s)
Thread-8 run 2 time(s)
Create Thread-9
Create Thread-10
Thread-10 run 1 time(s)
Thread-10 run 2 time(s)
Create Thread-11
Thread-9 run 1 time(s)
Thread-9 run 2 time(s)
Thread-6 run 1 time(s)
Thread-6 run 2 time(s)
Thread-3 run 1 time(s)
Thread-3 run 2 time(s)
Create Thread-12
Create Thread-13
Create Thread-14
Thread-12 run 1 time(s)
Thread-12 run 2 time(s)
Thread-13 run 1 time(s)
Thread-13 run 2 time(s)
Create Thread-15
Thread-15 run 1 time(s)
Thread-15 run 2 time(s)
Create Thread-16
Thread-16 run 1 time(s)
Thread-16 run 2 time(s)
Create Thread-17
Create Thread-18
Create Thread-19
Thread-14 run 1 time(s)
Thread-14 run 2 time(s)
Thread-17 run 1 time(s)
Thread-17 run 2 time(s)
Thread-18 run 1 time(s)
Thread-18 run 2 time(s)
Thread-19 run 1 time(s)
Thread-19 run 2 time(s)
Thread-11 run 1 time(s)
Thread-11 run 2 time(s)
本文出自 “子 孑” 博客，請務必保留此出處 http://zhangjunhd.blog.51cto.com/113473/70068
