從頭認識多執行緒-2.22 內部類的同步機制跟普通類相同
這一章節主要討論內部類的同步機制跟普通類相同。
1.當同步方法的時候
package com.ray.deepintothread.ch02.topic_22; /** * * @author RayLee * */ public class SynchOfInnerClass { class InnerClass { private int id = 0; public synchronized void service_1() throws InterruptedException { for (int i = 0; i < 5; i++) { System.out.println(Thread.currentThread().getName() + " id:" + id++); Thread.sleep(50); } } public synchronized void service_2() throws InterruptedException { for (int i = 0; i < 5; i++) { System.out.println(Thread.currentThread().getName() + " id:" + id++); Thread.sleep(100); } } } public InnerClass getInnerClass() { return new InnerClass(); } public static void main(String[] args) { SynchOfInnerClass synchOfInnerClass = new SynchOfInnerClass(); InnerClass innerClass = synchOfInnerClass.getInnerClass(); Thread thread = new Thread(new Runnable() { public void run() { try { innerClass.service_1(); } catch (InterruptedException e) { e.printStackTrace(); } } }); thread.start(); Thread thread2 = new Thread(new Runnable() { public void run() { try { innerClass.service_2(); } catch (InterruptedException e) { e.printStackTrace(); } } }); thread2.start(); } }
輸出:
Thread-0 id:0
Thread-0 id:1
Thread-0 id:2
Thread-0 id:3
Thread-0 id:4
Thread-1 id:5
Thread-1 id:6
Thread-1 id:7
Thread-1 id:8
Thread-1 id:9
2.當同步程式碼塊的時候
package com.ray.deepintothread.ch02.topic_22; /** * * @author RayLee * */ public class SynchOfInnerClass2 { class InnerClass { private int id = 0; private Object object = new Object(); public void service_1() throws InterruptedException { synchronized (object) { for (int i = 0; i < 5; i++) { System.out.println(Thread.currentThread().getName() + " id:" + id++); Thread.sleep(50); } } } public void service_2() throws InterruptedException { synchronized (object) { for (int i = 0; i < 5; i++) { System.out.println(Thread.currentThread().getName() + " id:" + id++); Thread.sleep(100); } } } } public InnerClass getInnerClass() { return new InnerClass(); } public static void main(String[] args) { SynchOfInnerClass2 synchOfInnerClass = new SynchOfInnerClass2(); InnerClass innerClass = synchOfInnerClass.getInnerClass(); Thread thread = new Thread(new Runnable() { public void run() { try { innerClass.service_1(); } catch (InterruptedException e) { e.printStackTrace(); } } }); thread.start(); Thread thread2 = new Thread(new Runnable() { public void run() { try { innerClass.service_2(); } catch (InterruptedException e) { e.printStackTrace(); } } }); thread2.start(); } }
輸出:
Thread-0 id:0
Thread-0 id:1
Thread-0 id:2
Thread-0 id:3
Thread-0 id:4
Thread-1 id:5
Thread-1 id:6
Thread-1 id:7
Thread-1 id:8
Thread-1 id:9
上面的兩種方式都是可以實現同步機制,使得資料保持一致,不會出現髒讀
3.當同步方法與同步程式碼塊同時出現的時候
package com.ray.deepintothread.ch02.topic_22; /** * * @author RayLee * */ public class SynchOfInnerClass3 { class InnerClass { private int id = 0; private Object object = new Object(); public void service_1() throws InterruptedException { synchronized (object) { for (int i = 0; i < 5; i++) { System.out.println(Thread.currentThread().getName() + " id:" + id++); Thread.sleep(50); } } } public synchronized void service_2() throws InterruptedException { for (int i = 0; i < 5; i++) { System.out.println(Thread.currentThread().getName() + " id:" + id++); Thread.sleep(100); } } } public InnerClass getInnerClass() { return new InnerClass(); } public static void main(String[] args) { SynchOfInnerClass3 synchOfInnerClass = new SynchOfInnerClass3(); InnerClass innerClass = synchOfInnerClass.getInnerClass(); Thread thread = new Thread(new Runnable() { public void run() { try { innerClass.service_1(); } catch (InterruptedException e) { e.printStackTrace(); } } }); thread.start(); Thread thread2 = new Thread(new Runnable() { public void run() { try { innerClass.service_2(); } catch (InterruptedException e) { e.printStackTrace(); } } }); thread2.start(); } }
輸出:
Thread-0 id:0
Thread-1 id:1
Thread-0 id:2
Thread-1 id:3
Thread-0 id:4
Thread-0 id:5
Thread-0 id:6
Thread-1 id:6
Thread-1 id:7
Thread-1 id:8
從輸出可以看見,資料不同步,出現髒讀
4.當使用不同監視器來同步程式碼塊的時候
package com.ray.deepintothread.ch02.topic_22;
/**
*
* @author RayLee
*
*/
public class SynchOfInnerClass4 {
class InnerClass {
private int id = 0;
private Object object1 = new Object();
private Object object2 = new Object();
public void service_1() throws InterruptedException {
synchronized (object1) {
for (int i = 0; i < 5; i++) {
System.out.println(Thread.currentThread().getName() + " id:" + id++);
Thread.sleep(50);
}
}
}
public synchronized void service_2() throws InterruptedException {
synchronized (object2) {
for (int i = 0; i < 5; i++) {
System.out.println(Thread.currentThread().getName() + " id:" + id++);
Thread.sleep(100);
}
}
}
}
public InnerClass getInnerClass() {
return new InnerClass();
}
public static void main(String[] args) {
SynchOfInnerClass4 synchOfInnerClass = new SynchOfInnerClass4();
InnerClass innerClass = synchOfInnerClass.getInnerClass();
Thread thread = new Thread(new Runnable() {
public void run() {
try {
innerClass.service_1();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
thread.start();
Thread thread2 = new Thread(new Runnable() {
public void run() {
try {
innerClass.service_2();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
thread2.start();
}
}
輸出:
Thread-0 id:0
Thread-1 id:1
Thread-0 id:2
Thread-1 id:3
Thread-0 id:3
Thread-0 id:4
Thread-0 id:5
Thread-1 id:5
Thread-1 id:6
Thread-1 id:7
上面的兩種情況就會出現資料不同步的現象。
總結:這一章節主要展示內部類的同步機制跟普通類相同。
這一章節就到這裡,謝謝
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