//This may be the only newCachedThreadPool used in a project, the others are the size of a new fixed
public static ExecutorService exec = Executors.newCachedThreadPool();
private static List<String> userList;
static {
userList=new ArrayList<String>();
for (int i = 0; i < 100; i++){
userList.add(String.valueOf(i));
}
}
/**
* Use semaphore to control the number of threads
*/
public static void simpleSemaphore() {
// Build maximum thread concurrency
final Semaphore sem = new Semaphore (10);
final Semaphore sycSem = new Semaphore(5, true);//Non-competitive locks are used here
//Simulate 100 customer visits
for (final String user:userList) {
Runnable run = new Runnable() {
public void run() {
try {
sem.acquire();//Get permission
System.out.println(user + "User enters----");
sem.release();//Release access
System.out.println("There are " + sem.availablePermits() + " thread spaces available after access");
} catch (InterruptedException e) {
e.printStackTrace ();
}
}
};
exec.execute(run);
}
exec.shutdown();
}
Results of the
0 users enter ---- There are still 10 thread spaces available after access 1 User enters ---- There are still 9 thread spaces that can be used after access 16 users enter ---- There are still 9 thread spaces that can be used after access 6 users enter ---- There are still 9 thread spaces that can be used after access 19 users enter ---- There are still 9 thread spaces that can be used after access 23 users enter---- There are still 9 thread spaces that can be used after access 26 users enter ----
What should I do if the users above are replaced by thread pools?
//This may be the only newCachedThreadPool used in a project, the others are the size of a new fixed
public static ExecutorService exec = Executors.newCachedThreadPool();
private static BlockingQueue<TaskPool> taskPools = new ArrayBlockingQueue<TaskPool>(1000);
private String user;
public static void addPoolTask(TaskPool user) {
if (taskPools.size() < 1000) {//It is recommended to add an initialization value
taskPools.add(user);
} else {
// transfer or do other processing
}
}
/**
* Use semaphore to control the number of threads
*/
public static void simpleSemaphore() {
// Build maximum thread concurrency
final Semaphore sem = new Semaphore (10);
final Semaphore sycSem = new Semaphore(5, true);//Non-competitive locks are used here
//Simulate 100 customer visits
while (taskPools.size() > 0) {
try {
final TaskPool taskPool = taskPools.take();
Runnable run = new Runnable() {
public void run() {
try {
sem.acquire();//Get permission
//Execute the corresponding task pool thing here
taskPool.excute();
sem.release();//Release access
System.out.println("thread pool" + taskPool.toString() + "after access" + sem.availablePermits() + "thread space can be used");
} catch (InterruptedException e) {
e.printStackTrace ();
}
}
};
exec.execute(run);
} catch (InterruptedException e) {
e.printStackTrace ();
}
}
exec.shutdown();
}
Multi-thread pool management based on user expansion
public interface TaskPool {
void excute();
}
public class MyFirstPoolTask implements TaskPool {
public ExecutorService exec = Executors.newFixedThreadPool(1);
private int init;
private int max = 10;
public MyFirstPoolTask(int init) {
if (max < init)
System.out.println("The value is too large");
this.exec = Executors.newFixedThreadPool(init);
}
public void excute() {
for (int i = 0; i < 5; i++) {
final int z = i;
Runnable rn = new Runnable() {
public void run() {
System.out.println("MyFirstPoolTask does my business processing"+Thread.currentThread().getName());
}
};
exec.execute(rn);
}
exec.shutdown();
}
}
public class MySecondPoolTask implements TaskPool {
public ExecutorService exec = Executors.newFixedThreadPool(1);
private int init;
private int max = 10;
public MySecondPoolTask(int init) {
if (max < init)
System.out.println("The value is too large");
this.exec = Executors.newFixedThreadPool(init);
}
public void excute() {
for (int i = 0; i < 5; i++) {
final int z = i;
Runnable rn = new Runnable() {
public void run() {
System.out.println("MySecondPoolTask does my business processing"+Thread.currentThread().getName());
}
};
exec.execute(rn);
}
exec.shutdown();
}
}
result after execution
The thread pool test.com.jd.hotel.janleTest.MyFirstPoolTask@2678a212 still has 9 thread spaces to use after accessing MyFirstPoolTask does my business processing pool-3-thread-3 MyFirstPoolTask does my business processing pool-3-thread-3 MyFirstPoolTask does my business processing pool-3-thread-3 The thread pool test.com.jd.hotel.janleTest.MySecondPoolTask@151a64ed still has 10 thread spaces to use after accessing MySecondPoolTask for my business processing pool-5-thread-1 MySecondPoolTask for my business processing pool-5-thread-1 MyFirstPoolTask does my business processing pool-3-thread-1 MySecondPoolTask for my business processing pool-5-thread-4 MySecondPoolTask for my business processing pool-5-thread-2 MyFirstPoolTask for my business processing pool-3-thread-2 MySecondPoolTask for my business processing pool-5-thread-3