import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Random;
import java.util.Set;
import java.util.TreeMap;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
public class Test {
public static void main(String[] args) throws Exception{
List list = new ArrayList();
List l = new LinkedList();
HashMap m;
Hashtable t;
TreeMap tr; //红黑树
HashSet hs;
int i = (25*3)/2 ;
System.out.println(i);
Integer in;
Properties props = System.getProperties();
Object s = props.get("java.lang.Integer.IntegerCache.high");
System.out.println(s);
Integer i1 = new Integer(2000);
System.out.println(i1 == 2000);
System.out.println(i1.equals(2000));
Student s1 = new Student();
Student s2 = new Student();
System.out.println(s1 == s2);
System.out.println(s1.equals(s2));
String t1 = new String("a");
String t2 = new String("a");
System.out.println(t1 == t2);
System.out.println(t1.equals(t2));
String t11 = new String("a");
String t21 = "a";
System.out.println(t21);
System.out.println(t11.equals(t21));
Map<Student, Object> mp = new HashMap<Student, Object>(); //hashCode()
mp.put(s1, null);
//s2.setId(1);
mp.put(s2, null);
System.out.println(mp.size());
//线程池
ExecutorService executorService = Executors.newSingleThreadExecutor();
Thread th1 = new PrintThread("t1");
Thread th2 = new PrintThread("t2");
Thread th3 = new PrintThread("t3");
Thread th4 = new PrintThread("t4");
Thread th5 = new PrintThread("t5");
executorService.execute(th1);
executorService.execute(th2);
executorService.execute(th3);
executorService.execute(th4);
executorService.execute(th5);
executorService.shutdown();
//
ExecutorService exe = Executors.newFixedThreadPool(1);
Thread ta1 = new PrintThread("ta1");
Thread ta2 = new PrintThread("ta2");
Thread ta3 = new PrintThread("ta3");
Thread ta4 = new PrintThread("ta4");
Thread ta5 = new PrintThread("ta5");
exe.execute(ta1);
exe.execute(ta2);
exe.execute(ta3);
exe.execute(ta4);
exe.execute(ta5);
exe.shutdown();
//
ExecutorService exe2 = Executors.newFixedThreadPool(2);
Thread tb1 = new PrintThread("tb1");
Thread tb2 = new PrintThread("tb2");
Thread tb3 = new PrintThread("tb3");
Thread tb4 = new PrintThread("tb4");
Thread tb5 = new PrintThread("tb5");
exe2.submit(tb1);
exe2.submit(tb2);
exe2.submit(tb3);
exe2.submit(tb4);
exe2.submit(tb5);
exe2.submit(tb5);
exe2.submit(tb5);
exe2.shutdown();
//返回值
ExecutorService exe3 = Executors.newSingleThreadExecutor();
Set<Callable<String>> callables = new HashSet<Callable<String>>();
callables.add(new Callable<String>() {
public String call() throws Exception {
return "Task 1";
}
});
callables.add(new Callable<String>() {
public String call() throws Exception {
return "Task 2";
}
});
callables.add(new Callable<String>() {
public String call() throws Exception {
return "Task 3";
}
});
System.out.println("..");
List<Future<String>> futures = exe3.invokeAll(callables);
System.out.println("....");
for(Future<String> future : futures){
System.out.println("future.get = " + future.get());
}
System.out.println("......");
exe3.shutdown();
//调度
// 创建一个线程池，它可安排在给定延迟后运行命令或者定期地执行。
ScheduledExecutorService pool = Executors.newScheduledThreadPool(2);
// 创建实现了Runnable接口对象，Thread对象当然也实现了Runnable接口
Thread t31 = new PrintThread("s31");
Thread t32 = new PrintThread("s32");
Thread t33 = new PrintThread("s33");
// 将线程放入池中进行执行
pool.execute(t31);
// 使用延迟执行风格的方法
pool.schedule(t32, 1000, TimeUnit.MILLISECONDS);
pool.schedule(t33, 10, TimeUnit.MILLISECONDS);
// 关闭线程池
pool.shutdown();
}
}
class Student {
private int id;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Override
public boolean equals(Object obj) {
boolean f = false;
if(obj instanceof Student) {
Student s2 = (Student) obj;
if(this.id == s2.getId()) {
f = true;
}
}
return f;
}
@Override
public String toString() {
return String.valueOf(this.id);
}
@Override
public int hashCode() {
return this.id;
}
}
class PrintThread extends Thread{
public PrintThread(String name) {
super(name);
}
public void run() {
int t = new Random().nextInt(1000);
try {
Thread.sleep(t);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(this.getName() + " " + t);
}
}