一手遮天 Android - 异步和多线程: ThreadPool 的关闭
示例如下:
/async/ThreadPoolDemo2.java
/**
* ThreadPool 的关闭（线程池用于控制最大线程数，以及复用空闲线程）
*
* shutdown() - 将线程池的 isShutdown 状态设置为 true，不允许再向线程池中添加任务，等线程池中的所有任务都执行完毕后线程池就会被关闭
* shutdownNow() - 将线程池的 isShutdown 状态设置为 true，不允许再向线程池中添加任务，未执行的任务不会再执行，调用每个线程的 interrupt() 方法，等线程池中的所有任务都执行完毕后线程池就会被关闭
* awaitTermination() - 阻塞并等待指定的时间，然后判断线程池中的所有任务是否都执行完毕了，如果线程池中的所有任务都执行完毕了则 isTerminated 状态为 true
*
* 注：如果线程中有 io 阻塞的话，先要把这个 io 干掉
*/
package com.webabcd.androiddemo.async;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import com.webabcd.androiddemo.R;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
public class ThreadPoolDemo2 extends AppCompatActivity {
private TextView _textView1;
private Button _button1;
private Button _button2;
private Button _button3;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_async_threadpooldemo2);
_textView1 = (TextView) findViewById(R.id.textView1);
_button1 = (Button) findViewById(R.id.button1);
_button2 = (Button) findViewById(R.id.button2);
_button3 = (Button) findViewById(R.id.button3);
sample_shutdown();
sample_shutdownNow();
sample_awaitTermination();
}
class MyThread extends Thread {
public MyThread(String name) {
super(name);
}
@Override
public void run() {
try {
Thread.sleep(1000);
writeMessage(String.format("pool thread id:%d, task name:%s", Thread.currentThread().getId(), this.getName()));
} catch (InterruptedException e) {
writeMessage(this.getName() + ": " + e.toString());
}
}
}
private void sample_shutdown() {
_button1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
clearMessage();
// 创建一个大小为 3 的线程池
ExecutorService pool = Executors.newFixedThreadPool(3);
// 创建需要处理的 5 个任务，并添加到线程池中
for (int i = 0; i < 5; i++) {
Thread thread = new Thread(new MyThread("thread " + i));
// 将指定的任务添加到线程池
pool.execute(thread);
}
// shutdown()
pool.shutdown();
try {
// shutdown() 后如果再添加任务到线程池就会引发异常
pool.execute(new Thread(new MyThread("myThread")));
}
catch (Exception e) {
writeMessage(e.toString());
}
writeMessage("isShutdown: " + pool.isShutdown() + " isTerminated: " + pool.isTerminated());
}
});
}
private void sample_shutdownNow() {
_button2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
clearMessage();
// 创建一个大小为 3 的线程池
ExecutorService pool = Executors.newFixedThreadPool(3);
// 创建需要处理的 5 个任务，并添加到线程池中
for (int i = 0; i < 5; i++) {
Thread thread = new Thread(new MyThread("thread " + i));
thread.setName("task " + i);
// 将指定的任务添加到线程池
pool.execute(thread);
}
// shutdownNow()（调用每个线程的 interrupt() 方法，未执行的任务不会再执行）
pool.shutdownNow();
// 获取 shutdownNow() 后未执行的任务列表（这些任务不会再执行）
List<Runnable> list = pool.shutdownNow();
for (Runnable runnable : list) {
Thread thread = (Thread) runnable;
writeMessage(thread.getName() + ": 未执行");
}
try {
// shutdownNow() 后如果再添加任务到线程池就会引发异常
pool.execute(new Thread(new MyThread("myThread")));
}
catch (Exception e) {
writeMessage("myThread: " + e.toString());
}
writeMessage("isShutdown: " + pool.isShutdown() + " isTerminated: " + pool.isTerminated());
}
});
}
private void sample_awaitTermination() {
_button3.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
clearMessage();
// 创建一个大小为 3 的线程池
final ExecutorService pool = Executors.newFixedThreadPool(3);
// 创建需要处理的 5 个任务，并添加到线程池中
for (int i = 0; i < 5; i++) {
Thread thread = new Thread(new MyThread("thread " + i));
// 将指定的任务添加到线程池
pool.execute(thread);
}
// shutdown()
pool.shutdown();
try {
// shutdown() 后如果再添加任务到线程池就会引发异常
pool.execute(new Thread(new MyThread("myThread")));
}
catch (Exception e) {
writeMessage(e.toString());
}
new Thread(new Runnable() {
@Override
public void run() {
// 如果线程池中的所有任务都执行完毕了则 isTerminated 状态为 true
while (!pool.isTerminated()) {
try {
// 阻塞并等待指定的时间，返回值为 isTerminated 状态
boolean terminated = pool.awaitTermination(1, TimeUnit.SECONDS);
writeMessage("terminated: " + terminated);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
writeMessage("isShutdown: " + pool.isShutdown() + " isTerminated: " + pool.isTerminated());
}
}).start();
writeMessage("isShutdown: " + pool.isShutdown() + " isTerminated: " + pool.isTerminated());
}
});
}
private void writeMessage(final String message) {
runOnUiThread(new Runnable() {
@Override
public void run() {
_textView1.append(String.format("%s
", message));
}
});
}
private void clearMessage() {
runOnUiThread(new Runnable() {
@Override
public void run() {
_textView1.setText("");
}
});
}
}
/layout/activity_async_threadpooldemo2.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAllCaps="false"
android:text="shutdown"/>
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAllCaps="false"
android:text="shutdownNow"/>
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAllCaps="false"
android:text="awaitTermination"/>
</LinearLayout>
</LinearLayout>