生產消費例子：
用synchronized：
class Resource{
private String name;
private int count = 0;
private boolean flag = true;
public synchronized void set(String name){
while(!flag){
try {
wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(flag){
this.name = name;
System.out.println(Thread.currentThread().getName()+" 生產了 "+name+"
"+(++count));
}
flag = false;
notifyAll();
}
public synchronized void get(){
while(flag){
try {
wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(!flag){
System.out.println(Thread.currentThread().getName()+" 消費了 "+name+""+count);
}
flag = true;
notifyAll();
}
}
class Producer implements Runnable{
private Resource r;
Producer(Resource r){
this.r = r;
}
public void run(){
while(true){
r.set("Tom");
}
}
}
class Consumer implements Runnable{
private Resource r;
Consumer(Resource r){
this.r = r;
}
public void run(){
while(true){
r.get();
}
}
}
public class TradeDemo {
public static void main(String[] args){
Resource res = new Resource();
Producer p = new Producer(res);
Consumer c = new Consumer(res);
Thread t1 = new Thread(p);
Thread t2 = new Thread(p);
Thread t3 = new Thread(c);
Thread t4 = new Thread(c);
t1.start();
t2.start();
t3.start();
t4.start();
}
}
用Lock：
import java.util.concurrent.locks.*;
import org.junit.Test;
class Resources {
private String name;
private int count = 0;
private boolean flag = true;
private Lock lock = new ReentrantLock();
private Condition condition_pro = lock.newCondition();
private Condition condition_con = lock.newCondition();
public void set(String name) {
lock.lock();
try {
while (!flag) {
condition_pro.await();
}
if (flag) {
this.name = name;
System.out.println(Thread.currentThread().getName()
+ " 生產了 " + name + "" + (++count));
}
flag = false;
condition_con.signal();
} catch (InterruptedException e) {
System.out.println("生產exception");
} finally {
lock.unlock();
}
}
public void get() {
lock.lock();
try {
while (flag) {
condition_con.await();
}
if (!flag) {
System.out.println(Thread.currentThread().getName()
+ " 消費了 " + name + "" + count);
}
flag = true;
condition_pro.signal();
} catch (InterruptedException e) {
System.out.println("消費exception");
} finally {
lock.unlock();
}
}
}
class Producers implements Runnable {
private Resources r;
Producers(Resources r) {
this.r = r;
}
public void run() {
while (true) {
r.set("Tom");
}
}
}
class Consumers implements Runnable {
private Resources r;
Consumers(Resources r) {
this.r = r;
}
@Test
public void run() {
while (true) {
r.get();
}
}
}
public class TradeDemo2 {
public static void main(String[] args) {
Resources res = new Resources();
Producers p = new Producers(res);
Consumers c = new Consumers(res);
Thread t1 = new Thread(p);
Thread t2 = new Thread(p);
Thread t3 = new Thread(c);
Thread t4 = new Thread(c);
t1.start();
t2.start();
t3.start();
t4.start();
}
}
Dead lock:
public class DeadLockThread implements Runnable{
private int tickets = 100;
private boolean flag;
DeadLockThread(boolean flag){
this.flag = flag;
}
public void run(){
while(tickets>0){
if(flag){
synchronized(MyLock.locka){
System.out.println("if locka");
synchronized(MyLock.lockb){
System.out.println(Thread.currentThread().getName()+"..true.."+"if lockb "+tickets--);
}
}
}
else{
synchronized(MyLock.lockb){
System.out.println("else lockb");
synchronized(MyLock.locka){
System.out.println(Thread.currentThread().getName()+"..false.."+"else lockb "+tickets--);
}
}
}
}
}
}
class MyLock{
static Object locka = new Object();
static Object lockb = new Object();
}