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🎨 #1592 实现简单的redis分布式锁 RedisTemplateSimpleDistributedLock
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lkqm authored May 31, 2020
1 parent 0a2e4d8 commit 2446fa6
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package me.chanjar.weixin.common.redis;

import lombok.NonNull;
import lombok.RequiredArgsConstructor;
import me.chanjar.weixin.common.util.locks.RedisTemplateSimpleDistributedLock;
import org.springframework.data.redis.core.StringRedisTemplate;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

@RequiredArgsConstructor
public class RedisTemplateWxRedisOps implements WxRedisOps {
Expand Down Expand Up @@ -37,7 +38,7 @@ public void expire(String key, int expire, TimeUnit timeUnit) {
}

@Override
public Lock getLock(String key) {
return new ReentrantLock();
public Lock getLock(@NonNull String key) {
return new RedisTemplateSimpleDistributedLock(redisTemplate, key, 60 * 1000);
}
}
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package me.chanjar.weixin.common.util.locks;

import lombok.Getter;
import lombok.NonNull;
import org.jetbrains.annotations.NotNull;
import org.springframework.dao.DataAccessException;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.connection.RedisStringCommands;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;
import org.springframework.data.redis.core.types.Expiration;

import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

/**
* 实现简单的redis分布式锁, 支持重入, 不是红锁
*
* @see <a href="https://redis.io/topics/distlock">reids distlock</a>
*/
public class RedisTemplateSimpleDistributedLock implements Lock {

@Getter
private final StringRedisTemplate redisTemplate;
@Getter
private final String key;
@Getter
private final int leaseMilliseconds;

private final ThreadLocal<String> valueThreadLocal = new ThreadLocal<>();

public RedisTemplateSimpleDistributedLock(@NonNull StringRedisTemplate redisTemplate, int leaseMilliseconds) {
this(redisTemplate, "lock:" + UUID.randomUUID().toString(), leaseMilliseconds);
}

public RedisTemplateSimpleDistributedLock(@NonNull StringRedisTemplate redisTemplate, @NonNull String key, int leaseMilliseconds) {
if (leaseMilliseconds <= 0) {
throw new IllegalArgumentException("Parameter 'leaseMilliseconds' must grate then 0: " + leaseMilliseconds);
}
this.redisTemplate = redisTemplate;
this.key = key;
this.leaseMilliseconds = leaseMilliseconds;
}

@Override
public void lock() {
while (!tryLock()) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// Ignore
}
}
}

@Override
public void lockInterruptibly() throws InterruptedException {
while (!tryLock()) {
Thread.sleep(1000);
}
}

@Override
public boolean tryLock() {
String value = valueThreadLocal.get();
if (value == null || value.length() == 0) {
value = UUID.randomUUID().toString();
valueThreadLocal.set(value);
}
final byte[] keyBytes = key.getBytes(StandardCharsets.UTF_8);
final byte[] valueBytes = value.getBytes(StandardCharsets.UTF_8);
List<Object> redisResults = redisTemplate.executePipelined(new RedisCallback<String>() {
@Override
public String doInRedis(RedisConnection connection) throws DataAccessException {
connection.set(keyBytes, valueBytes, Expiration.milliseconds(leaseMilliseconds), RedisStringCommands.SetOption.SET_IF_ABSENT);
connection.get(keyBytes);
return null;
}
});
Object currentLockSecret = redisResults.size() > 1 ? redisResults.get(1) : redisResults.get(0);
return currentLockSecret != null && currentLockSecret.toString().equals(value);
}

@Override
public boolean tryLock(long time, @NotNull TimeUnit unit) throws InterruptedException {
long waitMs = unit.toMillis(time);
boolean locked = tryLock();
while (!locked && waitMs > 0) {
long sleep = waitMs < 1000 ? waitMs : 1000;
Thread.sleep(sleep);
waitMs -= sleep;
locked = tryLock();
}
return locked;
}

@Override
public void unlock() {
if (valueThreadLocal.get() != null) {
// 提示: 必须指定returnType, 类型: 此处必须为Long, 不能是Integer
RedisScript<Long> script = new DefaultRedisScript("if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end", Long.class);
redisTemplate.execute(script, Arrays.asList(key), valueThreadLocal.get());
valueThreadLocal.remove();
}
}

@Override
public Condition newCondition() {
throw new UnsupportedOperationException();
}

/**
* 获取当前锁的值
* return 返回null意味着没有加锁, 但是返回非null值并不以为着当前加锁成功(redis中key可能自动过期)
*/
public String getLockSecretValue() {
return valueThreadLocal.get();
}
}
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package me.chanjar.weixin.common.util.locks;

import lombok.SneakyThrows;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.testng.annotations.BeforeTest;
import org.testng.annotations.Test;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import static org.testng.Assert.*;

@Test(enabled = false)
public class RedisTemplateSimpleDistributedLockTest {

RedisTemplateSimpleDistributedLock redisLock;

StringRedisTemplate redisTemplate;

AtomicInteger lockCurrentExecuteCounter;

@BeforeTest
public void init() {
JedisConnectionFactory connectionFactory = new JedisConnectionFactory();
connectionFactory.setHostName("127.0.0.1");
connectionFactory.setPort(6379);
connectionFactory.afterPropertiesSet();
StringRedisTemplate redisTemplate = new StringRedisTemplate(connectionFactory);
this.redisTemplate = redisTemplate;
this.redisLock = new RedisTemplateSimpleDistributedLock(redisTemplate, 60000);
this.lockCurrentExecuteCounter = new AtomicInteger(0);
}

@Test(description = "多线程测试锁排他性")
public void testLockExclusive() throws InterruptedException {
int threadSize = 100;
final CountDownLatch startLatch = new CountDownLatch(threadSize);
final CountDownLatch endLatch = new CountDownLatch(threadSize);

for (int i = 0; i < threadSize; i++) {
new Thread(new Runnable() {
@SneakyThrows
@Override
public void run() {
startLatch.await();

redisLock.lock();
assertEquals(lockCurrentExecuteCounter.incrementAndGet(), 1, "临界区同时只能有一个线程执行");
lockCurrentExecuteCounter.decrementAndGet();
redisLock.unlock();

endLatch.countDown();
}
}).start();
startLatch.countDown();
}
endLatch.await();
}

@Test
public void testTryLock() throws InterruptedException {
assertTrue(redisLock.tryLock(3, TimeUnit.SECONDS), "第一次加锁应该成功");
assertNotNull(redisLock.getLockSecretValue());
String redisValue = this.redisTemplate.opsForValue().get(redisLock.getKey());
assertEquals(redisValue, redisLock.getLockSecretValue());

redisLock.unlock();
assertNull(redisLock.getLockSecretValue());
redisValue = this.redisTemplate.opsForValue().get(redisLock.getKey());
assertNull(redisValue, "释放锁后key会被删除");

redisLock.unlock();
}


}

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@@ -1,10 +1,10 @@
package com.github.binarywang.wxpay.bean.result;

import org.testng.*;
import org.testng.annotations.*;

import com.thoughtworks.xstream.XStream;
import me.chanjar.weixin.common.util.xml.XStreamInitializer;
import org.testng.Assert;
import org.testng.annotations.BeforeTest;
import org.testng.annotations.Test;

/**
* The type Wx pay send redpack result test.
Expand Down Expand Up @@ -68,6 +68,6 @@ public void loadFailureResult() {
Assert.assertEquals("FAIL", wxMpRedpackResult.getReturnCode());
Assert.assertEquals("FAIL", wxMpRedpackResult.getResultCode());
Assert.assertEquals("onqOjjmM1tad-3ROpncN-yUfa6uI", wxMpRedpackResult.getReOpenid());
Assert.assertEquals(1, wxMpRedpackResult.getTotalAmount());
Assert.assertEquals(Integer.valueOf(1), wxMpRedpackResult.getTotalAmount());
}
}

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