sharding-jdbc中MasterSlaveRouter的作用是什么
本篇文章为大家展示了sharding-jdbc中MasterSlaveRouter的作用是什么，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。
MasterSlaveRouter
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/router/masterslave/MasterSlaveRouter.java
@RequiredArgsConstructorpublic final class MasterSlaveRouter { private final MasterSlaveRule masterSlaveRule; private final boolean showSQL; /** * Route Master slave. * * @param sql SQL * @return data source names */ // TODO for multiple masters may return more than one data source public Collection route(final String sql) { Collection result = route(new SQLJudgeEngine(sql).judge().getType()); if (showSQL) { SQLLogger.logSQL(sql, result); } return result; } private Collection route(final SQLType sqlType) { if (isMasterRoute(sqlType)) { MasterVisitedManager.setMasterVisited(); return Collections.singletonList(masterSlaveRule.getMasterDataSourceName()); } return Collections.singletonList(masterSlaveRule.getLoadBalanceAlgorithm().getDataSource( masterSlaveRule.getName(), masterSlaveRule.getMasterDataSourceName(), new ArrayList<>(masterSlaveRule.getSlaveDataSourceNames()))); } private boolean isMasterRoute(final SQLType sqlType) { return SQLType.DQL != sqlType || MasterVisitedManager.isMasterVisited() || HintManager.isMasterRouteOnly(); }} MasterSlaveRouter的route方法使用masterSlaveRule来进行路由
MasterSlaveRule
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-common/src/main/java/org/apache/shardingsphere/core/rule/MasterSlaveRule.java
@Getterpublic class MasterSlaveRule { private final String name; private final String masterDataSourceName; private final Collection slaveDataSourceNames; private final MasterSlaveLoadBalanceAlgorithm loadBalanceAlgorithm; private final MasterSlaveRuleConfiguration masterSlaveRuleConfiguration; public MasterSlaveRule(final String name, final String masterDataSourceName, final Collection slaveDataSourceNames, final MasterSlaveLoadBalanceAlgorithm loadBalanceAlgorithm) { this.name = name; this.masterDataSourceName = masterDataSourceName; this.slaveDataSourceNames = slaveDataSourceNames; this.loadBalanceAlgorithm = null == loadBalanceAlgorithm ? new MasterSlaveLoadBalanceAlgorithmServiceLoader().newService() : loadBalanceAlgorithm; masterSlaveRuleConfiguration = new MasterSlaveRuleConfiguration(name, masterDataSourceName, slaveDataSourceNames, new LoadBalanceStrategyConfiguration(this.loadBalanceAlgorithm.getType(), this.loadBalanceAlgorithm.getProperties())); } public MasterSlaveRule(final MasterSlaveRuleConfiguration config) { name = config.getName(); masterDataSourceName = config.getMasterDataSourceName(); slaveDataSourceNames = config.getSlaveDataSourceNames(); loadBalanceAlgorithm = createMasterSlaveLoadBalanceAlgorithm(config.getLoadBalanceStrategyConfiguration()); masterSlaveRuleConfiguration = config; } private MasterSlaveLoadBalanceAlgorithm createMasterSlaveLoadBalanceAlgorithm(final LoadBalanceStrategyConfiguration loadBalanceStrategyConfiguration) { MasterSlaveLoadBalanceAlgorithmServiceLoader serviceLoader = new MasterSlaveLoadBalanceAlgorithmServiceLoader(); return null == loadBalanceStrategyConfiguration ? serviceLoader.newService() : serviceLoader.newService(loadBalanceStrategyConfiguration.getType(), loadBalanceStrategyConfiguration.getProperties()); } /** * Judge whether contain data source name. * * @param dataSourceName data source name * @return contain or not. */ public boolean containDataSourceName(final String dataSourceName) { return masterDataSourceName.equals(dataSourceName) || slaveDataSourceNames.contains(dataSourceName); }} MasterSlaveRule内置了loadBalanceAlgorithm、masterSlaveRuleConfiguration
MasterSlaveLoadBalanceAlgorithm
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-api/src/main/java/org/apache/shardingsphere/spi/masterslave/MasterSlaveLoadBalanceAlgorithm.java
public interface MasterSlaveLoadBalanceAlgorithm extends TypeBasedSPI { /** * Get data source. * * @param name master-slave logic data source name * @param masterDataSourceName name of master data sources * @param slaveDataSourceNames names of slave data sources * @return name of selected data source */ String getDataSource(String name, String masterDataSourceName, List slaveDataSourceNames);} MasterSlaveLoadBalanceAlgorithm接口继承了TypeBasedSPI接口，它定义了getDataSource方法；它有两个实现类分别是RandomMasterSlaveLoadBalanceAlgorithm、RoundRobinMasterSlaveLoadBalanceAlgorithm
RandomMasterSlaveLoadBalanceAlgorithm
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-common/src/main/java/org/apache/shardingsphere/core/strategy/masterslave/RandomMasterSlaveLoadBalanceAlgorithm.java
@Getter@Setterpublic final class RandomMasterSlaveLoadBalanceAlgorithm implements MasterSlaveLoadBalanceAlgorithm { private Properties properties = new Properties(); @Override public String getType() { return "RANDOM"; } @Override public String getDataSource(final String name, final String masterDataSourceName, final List slaveDataSourceNames) { return slaveDataSourceNames.get(new Random().nextInt(slaveDataSourceNames.size())); }} RandomMasterSlaveLoadBalanceAlgorithm使用Random().nextInt来进行随机
RoundRobinMasterSlaveLoadBalanceAlgorithm
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-common/src/main/java/org/apache/shardingsphere/core/strategy/masterslave/RoundRobinMasterSlaveLoadBalanceAlgorithm.java
@Getter@Setterpublic final class RoundRobinMasterSlaveLoadBalanceAlgorithm implements MasterSlaveLoadBalanceAlgorithm { private static final ConcurrentHashMap COUNTS = new ConcurrentHashMap<>(); private Properties properties = new Properties(); @Override public String getType() { return "ROUND_ROBIN"; } @Override public String getDataSource(final String name, final String masterDataSourceName, final List slaveDataSourceNames) { AtomicInteger count = COUNTS.containsKey(name) ? COUNTS.get(name) : new AtomicInteger(0); COUNTS.putIfAbsent(name, count); count.compareAndSet(slaveDataSourceNames.size(), 0); return slaveDataSourceNames.get(Math.abs(count.getAndIncrement()) % slaveDataSourceNames.size()); }} RoundRobinMasterSlaveLoadBalanceAlgorithm使用
Math.abs(count.getAndIncrement()) % slaveDataSourceNames.size()进行round robin
MasterSlaveRuleConfiguration
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-api/src/main/java/org/apache/shardingsphere/api/config/masterslave/MasterSlaveRuleConfiguration.java
@Getterpublic class MasterSlaveRuleConfiguration implements RuleConfiguration { private final String name; private final String masterDataSourceName; private final Collection slaveDataSourceNames; private final LoadBalanceStrategyConfiguration loadBalanceStrategyConfiguration; public MasterSlaveRuleConfiguration(final String name, final String masterDataSourceName, final Collection slaveDataSourceNames) { this(name, masterDataSourceName, slaveDataSourceNames, null); } public MasterSlaveRuleConfiguration(final String name, final String masterDataSourceName, final Collection slaveDataSourceNames, final LoadBalanceStrategyConfiguration loadBalanceStrategyConfiguration) { Preconditions.checkArgument(!Strings.isNullOrEmpty(name), "Name is required."); Preconditions.checkArgument(!Strings.isNullOrEmpty(masterDataSourceName), "MasterDataSourceName is required."); Preconditions.checkArgument(null != slaveDataSourceNames && !slaveDataSourceNames.isEmpty(), "SlaveDataSourceNames is required."); this.name = name; this.masterDataSourceName = masterDataSourceName; this.slaveDataSourceNames = slaveDataSourceNames; this.loadBalanceStrategyConfiguration = loadBalanceStrategyConfiguration; }} MasterSlaveRuleConfiguration定义了name、masterDataSourceName、slaveDataSourceNames、loadBalanceStrategyConfiguration属性
小结
MasterSlaveRouter的route方法使用masterSlaveRule来进行路由；MasterSlaveRule内置了loadBalanceAlgorithm、masterSlaveRuleConfiguration；MasterSlaveLoadBalanceAlgorithm接口继承了TypeBasedSPI接口，它定义了getDataSource方法；它有两个实现类分别是RandomMasterSlaveLoadBalanceAlgorithm、RoundRobinMasterSlaveLoadBalanceAlgorithm
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