Multi-thread programming-two ways to create a thread: two ways to create a thread

Multi-thread programming-two ways to create a thread: two ways to create a thread

1. Purpose

Create a thread to get a thread instance. This thread instance must have methods to control its own life cycle, such as enabling, waiting, and waking.

 

2. Create a Thread

Method 1: new Thread (), new Thread (String name)

1/** 2 * there are also differences between the two constructors: different Thread names 3 */4 public class Thread implements Runnable {5 private char name []; 6 7 // 1. 8/* 9 * Automatically generated names are of the form * "Thread-" + n, where n is an integer10 */11 public Thread () {12 init (null, null, "Thread-" + nextThreadNum (), 0); 13} 14 private static synchronized int nextThreadNum () {15 return threadInitNumber ++; 16} 17 // 2. 18 public Thread (String name ) {19 init (null, null, name, 0); 20} 21 // initialization thread-init ()? 22 private void init (ThreadGroup g, Runnable target, String name, long stackSize) {23 init (g, target, name, stackSize, null ); 24} 25 private void init (ThreadGroup g, Runnable target, String name, long stackSize, AccessControlContext acc) {26 if (name = null) {27 throw new NullPointerException ("name cannot be null"); 28} 29 this. name = name. toCharArray (); 30/** The following is the initialization thread code-omitted */31} 32}

 

Method 2: new Thread (Runnable run), new Thread (Runnable run, String name)

public interface Runnable {

      public abstract void run();

}

/** Overwrite and replace the current object with the "external Runnable object" (the purpose is to allow the injection object to have the management Thread of the Thread object) */public class Thread implements Runnable {private Runnable target; public void run () {if (target! = Null) {target. run (); // call the run () method of the "external thread object}// Except for other methods of run (), all objects are Thread. currentThread ()}

 

 

3. Create a custom thread

Method 1: Inherit java. lang. Thread

/**
* 1. constructor class
*/
Public class MyThread extends Thread {// @ Override // whether to overwrite the run () method of the parent class Object public void run () {// do something }}/**
* 2. Create an instance
*/Public class Main {public void static void main (String args) {Thread t = new MyThread ();// Create a Thread --> method 1                   
T. run (); // t's run () is called

        }}

 

Method 2: implement the Runnable interface

public class MyThread implements Runnable {    public run() {         //do something    }

public class Main{    public void static void main(String args){

             MyThread mt =new MyThread();

Thread t = new Thread (mt );// Create a Thread --> method 2------> Thread. currentThread () => main|This object => t|T <init> called
T. run (); ------> Thread. currentThread () => t | this object => t|MtRun () of is called
/** RemoveOther methods of run () are aimed at Thread. currentThread (), so */

T. start (); ------> Thread. currentThread () => t | this object => t| TThe start () of is called.

T. stop (); ------> Thread. currentThread () => t|This object => t| TThe stop () of is called.

        }

}

 

 

4. Resource Sharing

Example: class MyThread --> private int I = 5;

 

Method 1: do not share

public class MyThread extends Thread {
    private int i =5;    public void run() {         i--;
         while(i>0){
        System.out.println(this.currentThread().getName()+"："+i);
            }       }}

public class Main{    public void static void main(String args){             Thread t1 =new MyThread("t1");

             Thread t2 =new MyThread("t2");

                    t1.start();  

                    t2.start();       
    } 

  }

/** Output:
* T1: 4
* T2: 4
* T1: 3
* T2: 3
*....
*/

 

Method 2: Share

(Implementation of the Runnable interface)

 

Cause:

Private native void start0 ()