synchronized 会把整个对象加锁。比如 如果是 synchronized(this) 会把这个实例加锁。
部分方法虽然互斥，但是，依然会进行无效等待。
synchronized(this)
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| package com.redisc;
import lombok.extern.slf4j.Slf4j;
@Slf4j(topic = "c.Run")
public class Run {
public static void main(String[] args) throws Exception {
BigRoom bigRoom = new BigRoom();
new Thread(() -> {
try {
bigRoom.study();
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
new Thread(() -> {
try {
bigRoom.sleep();
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
}
}
@Slf4j(topic = "c.BigRoom")
class BigRoom {
public void sleep() throws InterruptedException {
synchronized (this) {
log.debug("sleep...");
Thread.sleep(2000);
}
}
public void study() throws InterruptedException {
synchronized (this) {
log.debug("study...");
Thread.sleep(1000);
}
}
}
|
synchronized(Object)
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| package com.redisc;
import lombok.extern.slf4j.Slf4j;
@Slf4j(topic = "c.Run")
public class Run {
public static void main(String[] args) throws Exception {
BigRoom bigRoom = new BigRoom();
new Thread(() -> {
try {
bigRoom.study();
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
new Thread(() -> {
try {
bigRoom.sleep();
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
}
}
@Slf4j(topic = "c.BigRoom")
class BigRoom {
private final Object studyRoom = new Object();
private final Object bedRoom = new Object();
public void sleep() throws InterruptedException {
synchronized (studyRoom) {
log.debug("sleep...");
Thread.sleep(2000);
}
}
public void study() throws InterruptedException {
synchronized (bedRoom) {
log.debug("study...");
Thread.sleep(1000);
}
}
}
|
