线程锁 Lock
Lock 相当于 当前对象的 synchronisiert
import Java.util.concurrent.locks.lock; import Java.util.concurrent.locks.reentrantlock; / * * Lock lock = new Reentrantlock (); * lock.lock (); lock.unlock (); * 类似于 synchronisiert , 但不能与 synchronisiert 混用 */ public class lockest {public static void main (String [] args) {endgültig äußere äußere = new LockTest (). New ober (); neuer Thread (new Runnable () {@Override public void run () {// Todo Auto-Generated-Methode Stub, während (wahr) {oUter.out1 ("Zhangxiaoxiao"); Outer.out2 ("lihuoming");}}}). Start (); neuer Thread (new Runnable () {@Override public void run () {// Todo Auto-Generated-Methode Stub, während (wahr) {oUter.out1 ("Zhangxiaoxiao"); Outer.out2 ("lihuoming");}}}). Start (); } class OUTER {lock lock = new Reentrantlock (); void out1 (String name) {lock.lock (); int len = name.length (); für (int i = 0; i <len; i ++) {System.out.print (name.charat (i)); } System.out.println (); lock.unlock (); } void out2 (String -Name) {lock.lock (); int len = name.length (); für (int i = 0; i <len; i ++) {System.out.print (name.charat (i)); } System.out.println (); lock.unlock (); }}}
读写锁 ReentranTreadWriteLock
读写锁 : 允许多条线程同时读;不能读中有写;不能写中有读;不能写中有写
import Java.util.hashMap; import Java.util.map; import Java.util.concurrent.locks.readwritelock; import Java.util.concurrent.locks.reentranTreadWriteLock; / * * 问题 : 设计一个 缓存机制 的 伪代码 伪代码 * 从集合中读取数据 , 读取不到 , 就写入 , 再考虑多线程并发的情况 */ public class ReadWriteLockTest2 {private map <String, Objekt> data = new HashMap <String, Objekt> (); private readWriteLock lock = new ReentranTreadWriteLock (); // 读写锁 öffentliches Objekt getInstance1 (String -Schlüssel, Objekt obj) {lock.readlock (). Lock (); Objektwert = null; try {value = data.get (Schlüssel); if (value == null) {// 一条线程进入这里 , lock.readlock (). Unlock (); // 读锁解了 , 其他线程就可能也到这了 lock.WriteLock (). lock (); // 只能有一条线程到这 写锁开启 写锁开启 要写入数据了 要写入数据了 if (data.get (key) == null) {value = obj; / *先判断数据 , 如果不存在 , 才写入 , , 因为 界时当写锁解除后 , 其他 线程 , , 判断到数据存在 , 就跳过了。就不会发生同时写入的情况 */ data.put (Schlüssel, Wert); } lock.WriteLock (). Unlock (); // 写完了 , 解锁 lock.readlock (). lock (); }} endlich {lock.readlock (). Unlock (); } Rückgabewert; }