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。
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incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/router/masterslave/MasterSlaveRouter.java
@RequiredArgsConstructor
public 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
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-common/src/main/java/org/apache/shardingsphere/core/rule/MasterSlaveRule.java
@Getter
public 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
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
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-common/src/main/java/org/apache/shardingsphere/core/strategy/masterslave/RandomMasterSlaveLoadBalanceAlgorithm.java
@Getter
@Setter
public 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
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-common/src/main/java/org/apache/shardingsphere/core/strategy/masterslave/RoundRobinMasterSlaveLoadBalanceAlgorithm.java
@Getter
@Setter
public 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
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-api/src/main/java/org/apache/shardingsphere/api/config/masterslave/MasterSlaveRuleConfiguration.java
@Getter
public 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
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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