Java Multithreading Introduction Knowledge and sample program _java

Why do I need multiple threads?

Simplification of the model, such as some programs are run by a number of relatively independent tasks:

The appearance of graphical interface, the blocking of input and output

Multi-core CPU for better utilization

The need for asynchronous behavior

Java Multi-Threading features:

The entry of the program main itself is a thread

Threads are concurrent, unordered execution

The threads are executed sequentially inside the thread

Share data

Java Multi-Threading risk:

Security risk: Because the order of operation of threads is indeterminate, some programs that run under a single thread can have unexpected results under multithreading.

Performance risk: Server throughput, responsiveness, resource consumption

Java multithreaded APIs:

Java can create threads in two forms: first, implement Runnable interface, second, inherit thread class.

Inheritance thread creation Threading sample code

Copy Code code as follows:

public class ThreadTest extends Thread {

public static void Main (string[] args) {
ThreadTest thread = new ThreadTest ();
Thread.Start ();
for (int i=0; i<10; i++) {
System.out.println ("main:" +i);
}
}

@Override
public void Run () {
for (int i=0; i<10; i++) {
System.out.println ("Thread:" +i);
}
}

}

Implementing runnable Creating Thread code

Copy Code code as follows:

Package Com.openrdp.thread.api;

public class Runnabletest implements Runnable {

public static void Main (string[] args) {
Runnabletest runnable = new Runnabletest ();
Thread thread = new Thread (runnable);
Thread.Start ();
for (int i=0; i<10; i++) {
System.out.println ("main:" +i);
}
}

@Override
public void Run () {
for (int i=0; i<10; i++) {
System.out.println ("Thread:" +i);
}
}

}

Java Thread Pooling Technology

Executors get Exceuctorservice thread pool code

Copy Code code as follows:

Package Com.openrdp.thread.api;

Import Java.util.concurrent.ExecutorService;
Import java.util.concurrent.Executors;

public class Treadpooltest {
public static void Main (string[] args) {
Executorservice ThreadPool = Executors.newfixedthreadpool (99);
Taskthread thread1 = new Taskthread ("T1");
Threadpool.execute (THREAD1);
Taskthread thread2 = new Taskthread ("T2");
Threadpool.execute (THREAD2);

}

Static Class Taskthread implements Runnable {
String param;
Public taskthread (String param) {
This.param = param;
}

@Override
public void Run () {

}
}
}