DAY11 (multi-threaded, wake-up mechanism, production consumer mode, multi-threaded life cycle)

A: Process:

Process refers to a program that is running. To be exact, when a program goes into memory, it becomes a process, and the process is a program that is in the process of running and has a certain independent function.

B: Thread:

A thread is an execution unit in a process that is responsible for the execution of a program in the current process, with at least one thread in a process. There can be multiple threads in a process, and this application can also be called a multithreaded program.

C: In short:

After a program runs at least one process, a process can contain multiple threads

Thread implementation

Two ways to implement

Inherit thread

public class MyThread extends thread{@Overridepublic void Run () {for (int i = 0; i <; i++) {System.out.println (getn Ame () + ":" +i);}}}

Test class

public class MyThread02 extends thread {@Overridepublic void run () {MyThread t=new MyThread ();//Create an object directly to create a thread        T.start ();}}    

　　

Implement Runnable

public class Mythreadimp implements Runnable{int num;public mythreadimp (int num) {this.num=num;} @Overridepublic void Run () {for (int i = 0; i < 5; i++) {System.out.println (Thread.CurrentThread (). GetName () +num++);}}

Test class

public class Test01 {public static void main (string[] args) {mythreadimp mt=new mythreadimp (10); Thread T=new thread (MT); T.setname ("Zhang San"); T.start (); Thread T1=new thread (MT); T1.setname ("John Doe"); T1.start ();}}

　　

Multithreading Security Issues

Thread Security = = Security of data

① whether there are multiple threads

② If you have shared data

③ If there are more than one statement to perform shared data

Workaround Synchronized Sync Lock

eg

public class MyThread implements Runnable {int tickets;public MyThread (int tickets) {this.tickets = tickets;} Object o = new Object (), @Overridepublic Void Run () {while (true) {synchronized (O) {if (Tickets > 1) {System.out.printl N (Thread.CurrentThread (). GetName () + "-" + tickets--);}}}}

Test class

        MyThread mt=new MyThread (100); Thread T=new thread (MT); T.setname ("Window 1"); Thread T2=new thread (MT); T2.setname ("Window 2"); Thread T3=new thread (MT); T3.setname ("Window 3"); T.start (); T2.start (); T3.start ();            

If you do not give the line Cheng will produce data chaos, may produce-1; we cannot predict the result.

In the method of locking, the other method is to give the method lock eg:

public class MYTHREAD01 implements runnable{static int tickets=100;public MyThread01 (int tickets) {this.tickets = Tickets ;} @Overridepublic void Run () {while (true) {method01 ()}} Private synchronized void method01 () {if (Tickets >= 1) {System.out.println (Thread.CurrentThread (). GetName () + "-" + ti ckets--);}}}

　　

The case of stealing red envelopes:

public class MyThread implements Runnable {int. Money;int count;public MyThread (int money, int count) {This.money = Money;t His.count = Count;} @Overridepublic void Run () {//generates a random number method ();} Private synchronized void method () {if (Count > 1 && Money! = 0) {Random r = new Random ();d ouble d = (r.nextint (money) + 1); money-= D; System.out.println (Thread.CurrentThread (). GetName () + ":" + D); count--;} else {System.out.println (Thread.CurrentThread (). GetName () + ":" + Money);}}}

Test class

public class Hongbao {public static void main (string[] args) {MyThread mt=new MyThread (10,3); Thread T=new thread (MT); T.setname ("Zhang San"); T.start (); t.setpriority (10); Thread T1=new thread (MT); T1.setname ("John Doe"); T1.start (); Thread T2=new thread (MT); T2.setname ("Li"); T2.start ();}}

　　

Production Consumer Model:

Explains the multi-threaded wake-up mechanism (notify () is the method in object)

Using case columns in multi-threading

Product because just do test use not write full

public class Student {String  name;int Age;boolean flag;}

　　

Producers wait if consumers do not have consumer products and only consume producers to produce them.

public class Stthread implements Runnable {private Student s;public stthread (Student s) {THIS.S = s;} int x; @Overridepublic void Run () {while (true) {synchronized (s) {if (S.flag) {///if flag=true; it means that there are already objects  that have not yet been consumed, Then wait for try {s.wait ();} catch (Interruptedexception e) {e.printstacktrace ();} Wait for}if (x% 2! = 0) {s.name = "Zhao Yun"; s.age =;} else {s.name = "Zhang Fei"; s.age = 22;} x++;s.flag=true;//Modify Tag s.notify ();//Wake}}}}

　　

Consumers will wait for something to consume if they have nothing to consume.

public class Gtthread implements Runnable {private Student s;public gtthread (Student s) {THIS.S = s;} @Overridepublic void Run () {while (true) {//guaranteed to wait in synchronized (s) {if (!s.flag) {//flag=false) waits for the  student object to produce a try { S.wait ();//Thread Wait} catch (Interruptedexception e) {e.printstacktrace ();}} System.out.println (S.name + ":" + s.age); s.flag=false;s.notify ();}}}

　　

Test class

public class Test {public static void main (string[] args) {Student s=new Student (); Stthread st=new Stthread (s); Gtthread gt=new Gtthread (s); Thread T1=new Thread (ST); Thread t2=new thread (GT); T1.start (); T2.start ();}}

Output results

Output: Zhao Yun: 44 Zhang Fei: 22 Zhao Yun: 44 Zhang Fei: 22 Zhao Yun: 44 Zhang Fei: 22 Zhao Yun: 44 ... the cycle continues

　　

The life cycle of a thread

DAY11 (multi-threaded, wake-up mechanism, production consumer mode, multi-threaded life cycle)