下面對synchronized作用于方法進(jìn)行了測試，從結(jié)果可以看出，synchronized作用于方法的時候，鎖住的是整個對象宗挥，其他的所有的synchronized操作包括獲取對象中的屬性的的鎖的操作都需要等待當(dāng)前方法執(zhí)行完畢釋放鎖之后才能執(zhí)行，而非synchronized方法則不用等待鎖种蝶，可以直接執(zhí)行契耿，這就需要注意沒有加同步標(biāo)志的代碼塊的線程安全。

public class synchronizedTest {
    private int value=1;
    private Integer lo=new Integer("1");
    public void A(){
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        System.out.println(df.format(System.currentTimeMillis())+"a:"+value);
        value++;
        System.out.println(df.format(System.currentTimeMillis())+"a:"+value+" end!");
    }
    public synchronized void B(){
        value++;
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        System.out.println(df.format(System.currentTimeMillis())+"b:"+value);
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(df.format(System.currentTimeMillis())+"b:"+value+" end!");
    }
    public synchronized void C(){
        value++;
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        System.out.println(df.format(System.currentTimeMillis())+"c:"+value);
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(df.format(System.currentTimeMillis())+"c:"+value+" end!");
    }

    private synchronized void D(){
        synchronized (this){
            value++;
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            System.out.println(df.format(System.currentTimeMillis())+"d:"+value);
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(df.format(System.currentTimeMillis())+"d:"+value+" end!");
        }
    }

    private synchronized void F(){
        synchronized (lo){
            value++;
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            System.out.println(df.format(System.currentTimeMillis())+"f:"+value);
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(df.format(System.currentTimeMillis())+"f:"+value+" end!");
        }
    }

    public static  void  main(String[] args){
        synchronizedTest test=new synchronizedTest();
         Thread B=new Thread(()->{
             test.B();
         });
        Thread C=new Thread(()->{
            test.C();
        });
        Thread D=new Thread(()->{
            test.D();
        });
        Thread F=new Thread(()->{
            test.F();
        });
        B.start();
        C.start();
        D.start();
        F.start();
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        test.A();
    }
}

結(jié)果