Java multithreading implementation

Java multithreading implementation

• Inheriting the Thread

Inherit Thread, rewrite the run method inside, create an instance, and execute start Advantage: Simple code writing Disadvantage: no return value, inherit a class, can not inherit other classes, poor scalabilityCopy the code

• code

public class ThreadDemo extends Thread{

  @Override
  public void run(a) {
    System.out.println("Inherit Thread override run method"+Thread.currentThread().getName()); }}public static void main(String[] args) {
    ThreadDemo demo = new ThreadDemo();
    demo.setName("llll");
    demo.start();
  }
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• Implement Runnable

Create a Thread class using the Runnable interface implementation object as a parameter to the Thread object, call the Start interface advantage: Thread class can implement multiple interfaces, can inherit a class disadvantages: Without a return value, it cannot be started directly. Instead, it needs to be started by passing the dog in a Thread instanceCopy the code

• code

public class ThreadDemo2 implements Runnable{

  @Override
  public void run(a) {
    System.out.println("Implementing the Runnable interface"); }}public static void main(String[] args) {
   ThreadDemo2 demo2 = new ThreadDemo2();

// Thread thread = new Thread(()->{
// system.out.println (" anonymous inner class method ");
/ /});
    Runnable target;
    Thread thread = new Thread(demo2);
   thread.start();

  }
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• Through Callable and FutureTask

Create the callable interface implementation class, and implement the Call method, combined with FutureTask class to package the Callable object, to achieve multi-threading advantages: has high return value expansion disadvantages: The call method needs to be overridden to combine multiple classes such as FutureTask and ThreadCopy the code

• code

public class MyTask<Object> implements Callable {

  @Override
  public Object call(a) throws Exception {
    System.out.println("Callable"+Thread.currentThread().getName());
    return (Object) "Return value"; }}public class main1 {

  public static void main(String[] args) {

    MyTask myTask = new MyTask();

    FutureTask<Object> futureTask = new FutureTask<>(myTask);

    Thread thread = new Thread(futureTask);

    thread.setName("llll"); thread.start(); }}Copy the code

• Create a thread by creating a thread pool

Custom Runnable interface, implement the RUN method, create a thread pool, call the execution method and pass in the object Advantage: security, high performance, reuse threads disadvantage: jdK5 only support, need to use RunnableCopy the code

public class ThreadDemo4 implements Runnable {
​
    @Override
    public void run(a) {
        System.out.println(Multithreading via thread pool +runnable, name:+Thread.currentThread().getName()); }}public static void main(String[] args) {
        ExecutorService executorService = Executors.newFixedThreadPool(3);
​
        for(int i=0; i<10; i++){ executorService.execute(new ThreadDemo4());
        }
​
​
        System.out.println("Main thread name :"+Thread.currentThread().getName());
​
        // Close the thread pool
        executorService.shutdown();
}

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