com.neko233.skilltree.global.lock.mysql.MysqlExcludeGlobalLock Maven / Gradle / Ivy
package com.neko233.skilltree.global.lock.mysql;
import com.neko233.skilltree.global.lock.GlobalLock;
import com.neko233.skilltree.global.lock.mysql.utils.JdbcHelper;
import lombok.extern.slf4j.Slf4j;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLIntegrityConstraintViolationException;
import java.util.UUID;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
/**
* 不可重入锁, exclude Lock 排他
*/
@Slf4j
public class MysqlExcludeGlobalLock implements GlobalLock {
public static final String CREATE_TABLE_SQL = "create table if not exists neko233_global_lock_by_exclude ( " +
" id int unsigned auto_increment primary key, " +
" lock_name varchar(100) not null, " +
" expire_time bigint not null, " +
" thread_id varchar(100) not null, " +
" unique(lock_name) " +
" ) engine = myisam, charset uf8mb4 ";
private static final String SELECT_SQL_FORMAT = "select * from neko233_global_lock_by_exclude where lock_name=?";
private static final String UPDATE_SQL_FORMAT = "update neko233_global_lock_by_exclude set expire_time=? where lock_name=?";
private static final String INSERT_SQL_FORMAT = "insert into neko233_global_lock_by_exclude(lock_name,expire_time,thread_id) values(?,?,?)";
private static final String DELETE_SQL_FORMAT = "delete from neko233_global_lock_by_exclude where lock_name=?";
private final DataSource dataSource;
private final ExecutorService threadPoolExecutor = Executors.newSingleThreadExecutor();
private final int expireTimeMs;
private final long reletTimeMs; // 续租时间
private MysqlLockWatchDog mysqlLockWatchDog;
private final String threadId;
private final String lockName;
public MysqlExcludeGlobalLock(DataSource dataSource,
int expireTimeMs,
String lockName) {
this.dataSource = dataSource;
this.expireTimeMs = expireTimeMs;
this.reletTimeMs = this.expireTimeMs / 2;
this.lockName = lockName;
threadId = Thread.currentThread().getId() + "-" + UUID.randomUUID().toString();
mysqlLockWatchDog = new MysqlLockWatchDog(this::checkAndRelet, reletTimeMs, TimeUnit.MILLISECONDS);
try (Connection conn = dataSource.getConnection();
PreparedStatement ps = conn.prepareStatement(CREATE_TABLE_SQL);) {
boolean execute = ps.execute();
} catch (SQLException e) {
throw new RuntimeException("create table fail!", e);
}
}
@Override
public void lock() {
mysqlLockWatchDog.start();
while (true) {
try (Connection connection = dataSource.getConnection();
PreparedStatement statement = connection.prepareStatement(INSERT_SQL_FORMAT)) {
statement.setString(1, this.lockName);
statement.setLong(2, System.currentTimeMillis() + expireTimeMs);
statement.setString(3, this.threadId);
try {
//获取锁成功
if (statement.executeUpdate() > 0) {
log.info("获取锁成功");
break;
}
} catch (SQLIntegrityConstraintViolationException e) {
} catch (Exception e) {
e.printStackTrace();
}
//睡眠100ms继续获取锁，锁力度较大可修改这个时间
Thread.sleep(100);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
/**
* 查询锁 & 续租锁
*/
private void checkAndRelet() {
ResultSet resultSet = null;
PreparedStatement preparedStatement = null;
Connection connection = null;
try {
log.info("开始查询锁");
connection = dataSource.getConnection();
preparedStatement = connection.prepareStatement(SELECT_SQL_FORMAT);
preparedStatement.setString(1, this.lockName);
resultSet = preparedStatement.executeQuery();
if (resultSet.next()) {
final String threadId = resultSet.getString("thread_id");
final long expireTime = resultSet.getLong("expire_time");
log.debug("thread_id:{}", threadId);
if (this.threadId.equals(threadId)) {
//续租
log.info("续租中");
try (PreparedStatement updatePreparedStatement = connection.prepareStatement(UPDATE_SQL_FORMAT)) {
updatePreparedStatement.setLong(1, expireTime + reletTimeMs);
updatePreparedStatement.setString(2, this.lockName);
updatePreparedStatement.executeUpdate();
} catch (Exception e) {
throw new RuntimeException(e);
}
} else {
//检查时间是否过期
if (System.currentTimeMillis() > expireTime) {
log.info("锁：{}过期删除中", lockName);
delete();
}
}
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
JdbcHelper.gracefulClose(resultSet, preparedStatement, connection);
}
}
private void delete() {
log.info("删除锁");
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
connection = this.dataSource.getConnection();
preparedStatement = connection.prepareStatement(DELETE_SQL_FORMAT);
preparedStatement.setString(1, this.lockName);
if (preparedStatement.executeUpdate() == 1) {
log.info("刪除成功");
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
JdbcHelper.gracefulClose(preparedStatement, connection);
}
}
@Override
public boolean tryLock(long time,
TimeUnit unit) {
final Future future = threadPoolExecutor.submit(() -> {
try {
lock();
return 1;
} catch (Exception e) {
throw new RuntimeException(e);
}
});
try {
if (future.get(time, unit) == null) {
future.cancel(true);
return false;
}
return true;
} catch (Exception e) {
return false;
}
}
@Override
public void unlock() {
mysqlLockWatchDog.stop();
delete();
}
}