一、多线程(三种创建方式
Thread class 继承Thread类(重点)
Runnable 接口 实现Runnable接口(重点)
Callable接口 实现Callable接口
1、Thread 类
public class TestThread1 extends Thread{
@Override
public void run() {
for(int i=0;i<20;i++){
System.out.println("我在学习:"+i);
}
}
public static void main(String[] args){
TestThread1 testThread1 = new TestThread1();
testThread1.start();
for(int i=0;i<20;i++){
System.out.println("我在学习多线程:"+i);
}
}
}
示例如下:
public class TestThread2 extends Thread{
private String url;
private String name;
public TestThread2(String url,String name){
this.url=url;
this.name=name;
}
@Override
public void run() {
WebDownloader webDownloader = new WebDownloader();
webDownloader.downloader(url,name);
System.out.println("下载了的文件名为:"+name);
}
public static void main(String[] args) {
TestThread2 test1 = new TestThread2("https://preview.qiantucdn.com/58pic/10/54/62/36858PICpec2fD34c858PIC8e_PIC2018.jpg!kuan320","1.jpg");
TestThread2 test2 = new TestThread2("https://preview.qiantucdn.com/58pic/10/54/92/73e58PICfeAgnfth0e6pX_PIC2018.jpg!kuan320","2.jpg");
TestThread2 test3 = new TestThread2("https://preview.qiantucdn.com/58pic/00/97/59/91X58PICw8vDFXXbz2G58PICK_PIC2018.jpg!kuan320","3.jpg");
test1.start();
test2.start();
test3.start();
}
}
class WebDownloader{
public void downloader(String url,String name){
try {
FileUtils.copyURLToFile(new URL(url),new File(name));
} catch (IOException e) {
e.printStackTrace();
System.out.println("Io异常,downloader方法出现异常");
}
}
}
2、Runnable接口
public class TestThread3 implements Runnable{
@Override
public void run() {
for(int i=0;i<20;i++){
System.out.println("我在学习:"+i);
}
}
public static void main(String[] args){
TestThread3 testThread3 = new TestThread3();
new Thread(testThread3).start();
for(int i=0;i<20;i++){
System.out.println("我在学习多线程:"+i);
}
}
}
龟兔赛跑案例
public class Race implements Runnable{
private static String winner;
@Override
public void run() {
for(int i = 0; i <= 100; i++){
if(Thread.currentThread().getName().equals("兔子")&& i%10==0){
try {
Thread.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
boolean flag = gameOver(i);
if(flag){
break;
}
System.out.println(Thread.currentThread().getName()+"--->跑了"+i+"步");
}
}
private boolean gameOver(int steps){
if(winner != null){
return true;
}{
if(steps >= 100){
winner = Thread.currentThread().getName();
System.out.println("winner is"+winner);
return true;
}
}
return false;
}
public static void main(String[] args) {
Race race = new Race();
new Thread(race,"兔子").start();
new Thread(race,"乌龟").start();
}
}
3、Callable接口
public class TestCallable implements Callable<Boolean> {
private String url;
private String name;
public TestCallable(String url,String name){
this.url=url;
this.name=name;
}
@Override
public Boolean call() {
WebDownloader webDownloader = new WebDownloader();
webDownloader.downloader(url,name);
System.out.println("下载了的文件名为:"+name);
return true;
}
public static void main(String[] args) throws ExecutionException, InterruptedException {
TestCallable test1 = new TestCallable("https://preview.qiantucdn.com/58pic/10/54/62/36858PICpec2fD34c858PIC8e_PIC2018.jpg!kuan320","1.jpg");
TestCallable test2 = new TestCallable("https://preview.qiantucdn.com/58pic/10/54/92/73e58PICfeAgnfth0e6pX_PIC2018.jpg!kuan320","2.jpg");
TestCallable test3 = new TestCallable("https://preview.qiantucdn.com/58pic/00/97/59/91X58PICw8vDFXXbz2G58PICK_PIC2018.jpg!kuan320","3.jpg");
ExecutorService ser = Executors.newFixedThreadPool(3);
Future<Boolean> r1 = ser.submit(test1);
Future<Boolean> r2 = ser.submit(test2);
Future<Boolean> r3 = ser.submit(test3);
boolean rs1 = r1.get();
boolean rs2 = r2.get();
boolean rs3 = r3.get();
System.out.println(rs1);
System.out.println(rs2);
System.out.println(rs3);
ser.shutdownNow();
}
}
class WebDownloader{
public void downloader(String url,String name){
try {
FileUtils.copyURLToFile(new URL(url),new File(name));
} catch (IOException e) {
e.printStackTrace();
System.out.println("Io异常,downloader方法出现异常");
}
}
}