标签：rac call test ext 获取 服务 call() 结果 技术
继承Thread类
继承Thread类，重写run方法，通过线程类实例.start()方法开启线程。
public class TestThread1 extends Thread{
@override
public void run(){
System.out.println("线程run方法！");
}
public static void main(String){
new TestThread1().start();
}
}
实现Runnable接口
实现Runnable接口，重写run方法，通过new Thread(线程类实例).start()开启线程
推荐使用该方式，避免java的单继承局限性
public class TestThread2 implements Runnable{
@Override
public void run() {
System.out.println("线程run方法！");
}
public static void main(String[] args) {
new Thread(new TestThread2()).start();
}
}
实现Callable接口
实现Callable接口，重写call方法，call方法有返回值
启动方式：
* 创建执行服务
* 提交执行
* 获取结果
* 关闭服务
public class TestThread2 implements Callable{
@Override
public Boolean call() {
System.out.println("线程call方法！");
return true;
}
public static void main(String[] args) throws InterruptedException, ExecutionException {
TestThread2 t1 = new TestThread2();
TestThread2 t2 = new TestThread2();
TestThread2 t3 = new TestThread2();
//创建执行服务
ExecutorService ser = Executors.newFixedThreadPool(3);
//提交执行
Future<Boolean> r1 = ser.submit(t1);
Future<Boolean> r2 = ser.submit(t2);
Future<Boolean> r3 = ser.submit(t3);
//获取结果
boolean rs1 = r1.get();
boolean rs2 = r2.get();
boolean rs3 = r3.get();
//关闭服务
ser.shutdownNow();
}
多个线程同时操作同一资源，线程不安全，变量值紊乱
加锁
队列+锁(synchronized)
synchronized默认锁this，可以显示指定锁的对象来修改
1. synchronized修饰方法，线程安全方法
public class TestThreadSafe {
public static void main(String[] args) {
BuyTicket bt1 = new BuyTicket();
Thread thread1 = new Thread(bt1,"张三");
Thread thread2 = new Thread(bt1,"李四");
Thread thread3 = new Thread(bt1,"黄牛");
thread1.start();
thread2.start();
thread3.start();
}
}
class BuyTicket implements Runnable{
private int ticketNumber = 10;
private boolean flag = true;
@Override
public void run() {
while(flag) {
try {
buy();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public synchronized void buy() throws InterruptedException {
//买票
if(ticketNumber <= 0){
System.out.println("票卖完了！");
flag = false;
return;
}
Thread.sleep(100);
//Thread.yield();
System.out.println(Thread.currentThread().getName() + "买到了一张票，还剩下"+(--ticketNumber) + "张票！");
}
}
2. synchronized修饰代码块，线程安全代码块
public class TestThreadSafe {
public static void main(String[] args) {
BuyTicket bt1 = new BuyTicket();
Thread thread1 = new Thread(bt1,"张三");
Thread thread2 = new Thread(bt1,"李四");
Thread thread3 = new Thread(bt1,"黄牛");
thread1.start();
thread2.start();
thread3.start();
}
}
class BuyTicket implements Runnable{
private int ticketNumber = 10;
private boolean flag = true;
@Override
public void run() {
while(flag) {
System.out.println(Thread.currentThread().getName() + "准备买票" + flag);
try {
buy();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public void buy() throws InterruptedException {
synchronized(this){
//买票
if(ticketNumber <= 0){
flag = false;
System.out.println("票卖完了！");
return;
}
Thread.sleep(100);
//Thread.yield();
System.out.println(Thread.currentThread().getName() + "买到了一张票，还剩下"+(--ticketNumber) + "张票！");
}
}
}
3. 使用可重复锁ReentrantLock
import java.util.concurrent.locks.ReentrantLock;
public class TestLock {
public static void main(String[] args) {
BuyTicket bt1 = new BuyTicket();
Thread thread1 = new Thread(bt1,"张三");
Thread thread2 = new Thread(bt1,"李四");
Thread thread3 = new Thread(bt1,"黄牛");
thread1.start();
thread2.start();
thread3.start();
}
}
class BuyTicket implements Runnable{
private int ticketNumber = 1000;
private boolean flag = true;
//定义可重复锁
private final ReentrantLock lock = new ReentrantLock();
@Override
public void run() {
while(flag) {
try {
buy();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public void buy() throws InterruptedException {
lock.lock();
//买票
if(ticketNumber <= 0){
System.out.println("票卖完了！");
flag = false;
}else {
Thread.sleep(100);
//Thread.yield();
System.out.println(Thread.currentThread().getName() + "买到了一张票，还剩下"+(--ticketNumber) + "张票！");
}
lock.unlock();
}
}
死锁
两个以上的对象锁，每个线程互相占有对方需要的资源。形成死锁。
setPriority(int newPriority) 更改线程优先级 newPriority从1到10
static void sleep(long millis) 使当前正在执行的线程休眠指定毫秒，不会释放线程锁对象
void join() 线程合并，等待该线程终止
static void yield() 暂停当前正在执行的线程，执行其它线程
void interrupt() 中断线程
boolean isAlive() 该线程是否活跃
setDaemon(true) : 设置为守护线程
线程分为用户线程和守护线程
JVM虚拟机确保用户线程执行完毕
JVM虚拟机不用等待守护线程执行完毕
eg：后台记录操作日志，监控内存，垃圾回收等待
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标签：rac call test ext 获取 服务 call() 结果 技术
原文地址：https://www.cnblogs.com/lwh1019/p/13582027.html
