2.2.2synchronized同步代码块的使用

当两个并发线程访问同一个对象object中的synchronized(this)同步代码块时，一段时间内只能有一个线程执行，另一个线程必须等待期执行完才能执行。

package com.cky.bean;

/**
 * Created by chenkaiyang on 2017/12/6.
 */
public class ObjectService {
    public void serviceMethodA(){
        try {
            synchronized (this) {
                System.out.println("begin="+System.currentTimeMillis());
                Thread.sleep(2000);
                System.out.println("end="+System.currentTimeMillis());
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

    }

}

package com.cky.thread;

import com.cky.bean.ObjectService;

/**
 * Created by chenkaiyang on 2017/12/5.
 */
public class ThreadA extends Thread{
    private ObjectService service;
    public ThreadA(ObjectService service) {
        super();
        this.service = service;
    }

    @Override
    public void run() {
        super.run();
        service.serviceMethodA();
    }
}

package com.cky.thread;

import com.cky.bean.ObjectService;

/**
 * Created by chenkaiyang on 2017/12/5.
 */
public class ThreadB extends  Thread{
    private ObjectService service;
    public ThreadB(ObjectService service) {
        super();
        this.service = service;
    }

    @Override
    public void run() {
        super.run();
        service.serviceMethodA();
    }
}

package com.cky.test;

import com.cky.bean.ObjectService;
import com.cky.thread.ThreadA;
import com.cky.thread.ThreadB;

/**
 * Created by chenkaiyang on 2017/12/6.
 */
public class Test2 {
    public static void main(String[] args) {
        ObjectService objectService = new ObjectService();
        ThreadA a = new ThreadA(objectService);
        a.setName("a");
        ThreadB b = new ThreadB(objectService);
        b.setName("b");
        a.start();
        b.start();

    }
}

D:itjdk1.8injava -Didea.launcher.port=7535 "-Didea.launcher.bin.path=D:itideaIntelliJ IDEA 2016.3.3in" -Dfile.encoding=UTF-8 -classpath "D:itjdk1.8jrelibcharsets.jar;D:itjdk1.8jrelibdeploy.jar;D:itjdk1.8jrelibextaccess-bridge-64.jar;D:itjdk1.8jrelibextcldrdata.jar;D:itjdk1.8jrelibextdnsns.jar;D:itjdk1.8jrelibextjaccess.jar;D:itjdk1.8jrelibextjfxrt.jar;D:itjdk1.8jrelibextlocaledata.jar;D:itjdk1.8jrelibext
ashorn.jar;D:itjdk1.8jrelibextsunec.jar;D:itjdk1.8jrelibextsunjce_provider.jar;D:itjdk1.8jrelibextsunmscapi.jar;D:itjdk1.8jrelibextsunpkcs11.jar;D:itjdk1.8jrelibextzipfs.jar;D:itjdk1.8jrelibjavaws.jar;D:itjdk1.8jrelibjce.jar;D:itjdk1.8jrelibjfr.jar;D:itjdk1.8jrelibjfxswt.jar;D:itjdk1.8jrelibjsse.jar;D:itjdk1.8jrelibmanagement-agent.jar;D:itjdk1.8jrelibplugin.jar;D:itjdk1.8jrelib
esources.jar;D:itjdk1.8jrelib
t.jar;F:springboot	hreaddemooutproduction	hreaddemo;D:itideaIntelliJ IDEA 2016.3.3libidea_rt.jar" com.intellij.rt.execution.application.AppMain com.cky.test.Test2
begin=1512567935564
end=1512567937564
begin=1512567937564
end=1512567939564

结果表明：方法执行是同步的，但是效果没有提高，下面模拟提高效率