关于java读写锁的测试
package com.zang.concurrent.locks.rwlock;
import java.util.Random;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
/**
* 读写锁测试
* 写锁可降级为读锁
* 读锁可重用
*
* @author Zhang Qiang
* @Date 2019/9/17 17:04
*/
public class ReadWriteLockUsage {
private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock();
private final Lock readLock = readWriteLock.readLock();
private final Lock writeLock = readWriteLock.writeLock();
private static StringBuilder argString = new StringBuilder();
public static void main(String[] args) {
ReadWriteLockUsage readWriteLockUsage = new ReadWriteLockUsage();
// 循环创建线程获取锁
for (int i = 0; i < 10; i++) {
long next = (long) (new Random().nextFloat() * 1000);
Thread writeThread = new Thread(new Runnable() {
@Override
public void run() {
try {
Thread.sleep(next);
argString.delete(0,argString.length());
argString.append(next);
System.out.println(Thread.currentThread().getName() + " -> start" + ", next :" + next + ", argString:" + argString);
readWriteLockUsage.wreiter(argString.toString());
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
writeThread.setName("T_"+i);
writeThread.start();
Thread readThread = new Thread(new Runnable() {
@Override
public void run() {
try {
Thread.sleep(next);
readWriteLockUsage.reader(argString.toString());
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
readThread.start();
}
}
/**
* 读锁
*
* @param argString
* @return
*/
public void wreiter(String argString){
if (writeLock.tryLock()){
try {
argString += "_" +ClassLoader.getSystemClassLoader().getParent().toString();
Thread.sleep(200);
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
writeLock.unlock();
System.out.println("writeLock 已释放");
}
} else {
System.out.println("未获取到写锁");
}
}
/**
* 写锁
*
* @param argString
* @return
*/
public void reader(String argString){
readLock.lock();
try {
System.out.println("readLock ============== atgString: " + argString);
} finally {
readLock.unlock();
}
}
}
打印信息：
"D:Program FilesJavajdk1.8.0_202injava.exe" "-javaagent:D:Program FilesJetBrainsIntelliJ IDEA 2018.2.1libidea_rt.jar=56588:D:Program FilesJetBrainsIntelliJ IDEA 2018.2.1in" -Dfile.encoding=UTF-8 -classpath "D:Program FilesJavajdk1.8.0_202jrelibcharsets.jar;D:Program FilesJavajdk1.8.0_202jrelibdeploy.jar;D:Program FilesJavajdk1.8.0_202jrelibextaccess-bridge-64.jar;D:Program FilesJavajdk1.8.0_202jrelibextcldrdata.jar;D:Program FilesJavajdk1.8.0_202jrelibextdnsns.jar;D:Program FilesJavajdk1.8.0_202jrelibextjaccess.jar;D:Program FilesJavajdk1.8.0_202jrelibextjfxrt.jar;D:Program FilesJavajdk1.8.0_202jrelibextlocaledata.jar;D:Program FilesJavajdk1.8.0_202jrelibext ashorn.jar;D:Program FilesJavajdk1.8.0_202jrelibextsunec.jar;D:Program FilesJavajdk1.8.0_202jrelibextsunjce_provider.jar;D:Program FilesJavajdk1.8.0_202jrelibextsunmscapi.jar;D:Program FilesJavajdk1.8.0_202jrelibextsunpkcs11.jar;D:Program FilesJavajdk1.8.0_202jrelibextzipfs.jar;D:Program FilesJavajdk1.8.0_202jrelibjavaws.jar;D:Program FilesJavajdk1.8.0_202jrelibjce.jar;D:Program FilesJavajdk1.8.0_202jrelibjfr.jar;D:Program FilesJavajdk1.8.0_202jrelibjfxswt.jar;D:Program FilesJavajdk1.8.0_202jrelibjsse.jar;D:Program FilesJavajdk1.8.0_202jrelibmanagement-agent.jar;D:Program FilesJavajdk1.8.0_202jrelibplugin.jar;D:Program FilesJavajdk1.8.0_202jrelib esources.jar;D:Program FilesJavajdk1.8.0_202jrelib t.jar;D:IdeaProjectgithub ettyGui argetclasses;D:MavenRepositoryio etty etty-all5.0.0.Alpha2 etty-all-5.0.0.Alpha2.jar;D:MavenRepositoryorgprojectlomboklombok1.18.8lombok-1.18.8.jar;D:MavenRepositorycomgoogleprotobufprotobuf-java3.7.1protobuf-java-3.7.1.jar;D:MavenRepository edisclientsjedis2.9.0jedis-2.9.0.jar;D:MavenRepositoryorgapachecommonscommons-pool22.4.2commons-pool2-2.4.2.jar;D:MavenRepositorycommons-iocommons-io2.4commons-io-2.4.jar;D:MavenRepositorycomgithubjavafakerjavafaker1.0.0javafaker-1.0.0.jar;D:MavenRepositoryorgapachecommonscommons-lang33.5commons-lang3-3.5.jar;D:MavenRepositoryorgyamlsnakeyaml1.23snakeyaml-1.23-android.jar;D:MavenRepositorycomgithubmifmifgenerex1.0.2generex-1.0.2.jar;D:MavenRepositorydkricsautomatonautomaton1.11-8automaton-1.11-8.jar;D:MavenRepositorycommons-configurationcommons-configuration1.8commons-configuration-1.8.jar;D:MavenRepositorycommons-langcommons-lang2.6commons-lang-2.6.jar;D:MavenRepositorycommons-loggingcommons-logging1.1.1commons-logging-1.1.1.jar;D:MavenRepositoryorgquartz-schedulerquartz2.3.0quartz-2.3.0.jar;D:MavenRepositorycommchangec3p0 .9.5.2c3p0-0.9.5.2.jar;D:MavenRepositorycommchangemchange-commons-java .2.11mchange-commons-java-0.2.11.jar;D:MavenRepositorycomzaxxerHikariCP-java62.3.13HikariCP-java6-2.3.13.jar;D:MavenRepositoryorgslf4jslf4j-api1.7.7slf4j-api-1.7.7.jar;D:MavenRepositoryorgslf4jslf4j-nop1.7.2slf4j-nop-1.7.2.jar;D:MavenRepositorycomaliyunaliyun-java-sdk-core3.0.0aliyun-java-sdk-core-3.0.0.jar;D:MavenRepositorycomaliyunaliyun-java-sdk-dm3.1.0aliyun-java-sdk-dm-3.1.0.jar;D:MavenRepositoryio eactivex xjava1.3.8 xjava-1.3.8.jar" com.zang.concurrent.locks.rwlock.ReadWriteLockUsage T_9 -> start, next :18, argString:18 readLock ============== atgString: 未获取到写锁 readLock ============== atgString: T_5 -> start, next :174, argString:174 T_6 -> start, next :364, argString:364 未获取到写锁 writeLock 已释放 readLock ============== atgString: 174 T_8 -> start, next :529, argString:529 T_3 -> start, next :622, argString:622 未获取到写锁 T_4 -> start, next :637, argString:637 未获取到写锁 T_7 -> start, next :661, argString:661 未获取到写锁 readLock ============== atgString: 529 readLock ============== atgString: 622 readLock ============== atgString: 622 readLock ============== atgString: 637 writeLock 已释放 T_0 -> start, next :750, argString:750 readLock ============== atgString: 750 未获取到写锁 T_1 -> start, next :773, argString:773 writeLock 已释放 readLock ============== atgString: 773 T_2 -> start, next :985, argString:985 writeLock 已释放 readLock ============== atgString: 985 Process finished with exit code 0