java 生產者和消費者

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生產者和消費者的例子

一、wait() / notify()方法

wait() / nofity()方法是基類Object的兩個方法，也就意味著所有Java類都會擁有這兩個方法，這樣，我們就可以為任何對象實現同步機制。

wait()方法：當緩衝區已滿/空時，生產者/消費者線程停止自己的執行，放棄鎖，使自己處於等等狀態，讓其他線程執行。

notify()方法：當生產者/消費者向緩衝區放入/取出一個產品時，向其他等待的線程發出可執行檔通知，同時放棄鎖，使自己處於等待狀態。

直接貼上代碼 用as

class Person{
private String name;
private String sex;

private Boolean isEmpty = Boolean.TRUE;

public void set(String name,String sex){
synchronized(this){
while(!isEmpty.equals(Boolean.TRUE)){
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
this.name=name;
try {
Thread.sleep(1);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
this.sex=sex;
isEmpty=Boolean.FALSE;
this.notifyAll();
}
}

public void get(){
synchronized(this){
while(!isEmpty.equals(Boolean.FALSE)){
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
String name=getName();
String sex=getSex();
System.out.println(name + " --> " + sex);
isEmpty=Boolean.TRUE;
this.notifyAll();
}
}

public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}

}

class Producer implements Runnable{
private Person p;
public Producer(Person p){
this.p=p;

}

@Override
public void run() {
// TODO Auto-generated method stub
for(int i=2;i<100;i++){
if(i%2==0){
p.set("李果", "女");
}else{
p.set("李凡", "男");
}
}
}

}
class Consumer implements Runnable{
private Person p;
public Consumer(Person p){
this.p=p;
}
@Override
public void run() {
// TODO Auto-generated method stub
for(int i=2;i<100;i++){
p.get();
}
}

}
public class Productor_ConsumerDemo {

public static void main(String[] args) {
// TODO Auto-generated method stub
Person p = new Person();
new Thread(new Producer(p)).start();
new Thread(new Consumer(p)).start();

new Thread(new Producer(p)).start();
new Thread(new Consumer(p)).start();
}

}

用Synchronized 同步方法

await() / signal()方法

在JDK5.0之後，Java提供了更加健壯的線程處理機制，包括同步、鎖定、線程池等，它們可以實現更細粒度的線程式控制制。await()和signal()就是其中用來做同步的兩種方法，它們的功能基本上和wait() / nofity()相同，完全可以取代它們，但是它們和新引入的鎖定機制Lock直接掛鈎，具有更大的靈活性。通過在Lock對象上調用newCondition()方法，將條件變數和一個鎖對象進行綁定，進而控制並發程式訪問競爭資源的安全。下面來看代碼：

class Person {
private String name;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getSex() {
return sex;
}

public void setSex(String sex) {
this.sex = sex;
}

private String sex;

private final ReentrantLock lock = new ReentrantLock();
private final Condition con = lock.newCondition();
private Boolean isEmpty = Boolean.TRUE;

public void set(String name, String sex) {
lock.lock();
while (!isEmpty.equals(Boolean.TRUE)) {
try {
con.await();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

try {
this.name = name;
Thread.sleep(1);
this.sex = sex;
isEmpty = Boolean.FALSE;
con.signal();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
lock.unlock();
}

}

public void get() {
lock.lock();
while (!isEmpty.equals(Boolean.FALSE)) {
try {
con.await();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

try {
String name = getName();

String sex = getSex();
System.out.println(name + " --> " + sex);
isEmpty = Boolean.TRUE;
con.signal();

} finally {
lock.unlock();
}
}
}

class Productor implements Runnable {
private Person p;

public Productor(Person p) {
this.p = p;
}

@Override
public void run() {
// TODO Auto-generated method stub
for (int i = 2; i < 100; i++) {
if (i % 2 == 0) {
p.set("李果", "女");
} else {
p.set("李雨軒", "男");
}
}
}

}

class Cosumer implements Runnable {
private Person p;

public Cosumer(Person p) {
this.p = p;
}

@Override
public void run() {
// TODO Auto-generated method stub
for (int i = 2; i < 100; i++) {
p.get();
}

}

}

public class Producer_Demo {

public static void main(String[] args) {
// TODO Auto-generated method stub
Person p = new Person();

new Thread(new Productor(p)).start();
new Thread(new Cosumer(p)).start();
}

}

java 生產者和消費者