下面两段代码有什么区别，有大神给答案吗，好像锁不同对象没什么区别啊code 1synchronized (A.class) { try { Thread.sleep(5000); } catch (InterruptedException e) { e.printStackTrace(); } }code 2synchronized (B.class) { try { Thread.sleep(5000); } catch (InterruptedException e) { e.printStackTrace(); } }
4 回答
慕桂英3389331
TA贡献2036条经验 获得超8个赞
好多人说没有区别，这样吧，直接上代码和结果吧
public class Test {
static Runnable lock = new Runnable() {
@Override
public void run() {
synchronized (A.class) {
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
};
static Runnable syncA = new Runnable() {
@Override
public void run() {
A.syncShowTime();
}
};
static Runnable syncB = new Runnable() {
@Override
public void run() {
B.syncShowTime();
}
};
static Runnable lockA = new Runnable() {
@Override
public void run() {
A.lockShowTime();
}
};
static Runnable lockB = new Runnable() {
@Override
public void run() {
B.lockShowTime();
}
};
static Runnable instA = new Runnable() {
@Override
public void run() {
A a = new A();
a.instShowTime();
}
};
static Runnable instB = new Runnable() {
@Override
public void run() {
B b = new B();
b.instShowTime();
}
};
public static void main(String args[]) {
try {
new Thread(lock).start();
Thread.sleep(1000);
System.out.println("S:" + (int) (System.currentTimeMillis() / 1000L));
new Thread(syncA).start();
new Thread(syncB).start();
new Thread(lockA).start();
new Thread(lockB).start();
new Thread(instA).start();
new Thread(instB).start();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
class A {
static synchronized void syncShowTime() {
System.out.println("A sync:" + (int) (System.currentTimeMillis() / 1000L));
}
static void lockShowTime() {
synchronized (A.class) {
System.out.println("A lock:" + (int) (System.currentTimeMillis() / 1000L));
}
}
void instShowTime() {
synchronized (A.class) {
System.out.println("A inst:" + (int) (System.currentTimeMillis() / 1000L));
}
}
}
class B {
static synchronized void syncShowTime() {
System.out.println("B sync:" + (int) (System.currentTimeMillis() / 1000L));
}
static void lockShowTime() {
synchronized (B.class) {
System.out.println("B lock:" + (int) (System.currentTimeMillis() / 1000L));
}
}
void instShowTime() {
synchronized (B.class) {
System.out.println("B inst:" + (int) (System.currentTimeMillis() / 1000L));
}
}
}
S:1469596337
B sync:1469596337
B lock:1469596337
B inst:1469596337
A inst:1469596341
A lock:1469596341
A sync:1469596341
千巷猫影
TA贡献1829条经验 获得超7个赞
我想题主的意思是synchronized后面的括号里面放A.class和B.class有什么区别，两段代码并不是共存的，楼上的哥们好像理解错题主意思了。如果楼主是这个问题的话，那基本没啥区别。如果这两段代码分别在同一个类的不同方法中，那两个线程可以同时访问同一个对象的这两个方法，并没有什么影响，因为是不同的锁。so，看题主你的问题是什么了
拉风的咖菲猫
TA贡献1995条经验 获得超2个赞
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