Java 多线程实现方式
新建线程
1.继承Thread，复写run
实现一个线程最简单的方法
1
2
3
4
5
| new Thread() {
public void run() {
System.out.println("I`am a thread!");
};
}.start();
|
2.实现runnable,实现run
runnable是一个接口类，使用的话，需要实现。
1
2
3
4
5
6
| new Thread(new Runnable() {
public void run() {
// TODO Auto-generated method stub
System.out.println("I`am a second thread!");
}
}).start();
|
3.利用jdk中Executor框架实现
Executors类，提供了一系列工厂方法用于创先线程池，返回的线程池都实现了ExecutorService接口。其中包括线程池，Executor，Executors，ExecutorService，CompletionService，Future，Callable等。
1
2
3
4
5
6
| ExecutorService executorService = Executors.newSingleThreadExecutor();
executorService.submit(new Runnable() {
public void run() {
System.out.println("I`am a thrid thread!");
}
});
|
带返回值的多线程
结合Future，Callable一起使用，可以取得多线程执行的返回值
1.第一种
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
| ExecutorService executorService = Executors.newFixedThreadPool(10);
List<Future<String>> results = new ArrayList<Future<String>>();
for( int i=0;i<10000;i++){
final int j = i;
Future<String> result = executorService.submit(new Callable<String>() {
public String call() throws Exception {
// TODO Auto-generated method stub
return "value"+j;
}
});
results.add(result);
}
for(Future<String>result :results){
System.out.println(result.get());//当线程没有执行完毕会阻塞
}
executorService.shutdown();
|
2.第二种
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
| ExecutorService executorService = Executors.newFixedThreadPool(10);
List<Callable<String>> tasks = new ArrayList<Callable<String>>();
for (int i = 0; i < 10000; i++) {
final int j = i;
tasks.add(new Callable<String>() {
public String call() throws Exception {
// TODO Auto-generated method stub
return "value" + j;
}
});
}
//此时还未执行
List<Future<String>> results = executorService.invokeAll(tasks);//未执行完成阻塞
for (Future<String> result : results) {
System.out.println(result.get());//当线程没有执行完毕会阻塞
}
executorService.shutdown();
|