怎么理解sharding-jdbc的ShardingMasterSlaveRouter

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主要研究一下sharding-jdbc的ShardingMasterSlaveRouter

ShardingMasterSlaveRouter

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/router/masterslave/ShardingMasterSlaveRouter.java

@RequiredArgsConstructorpublic final class ShardingMasterSlaveRouter {        private final Collection masterSlaveRules;        /**     * Route Master slave after sharding.     *      * @param sqlRouteResult SQL route result     * @return route result     */    public SQLRouteResult route(final SQLRouteResult sqlRouteResult) {        for (MasterSlaveRule each : masterSlaveRules) {            route(each, sqlRouteResult);        }        return sqlRouteResult;    }        private void route(final MasterSlaveRule masterSlaveRule, final SQLRouteResult sqlRouteResult) {        Collection toBeRemoved = new LinkedList<>();        Collection toBeAdded = new LinkedList<>();        for (TableUnit each : sqlRouteResult.getRoutingResult().getTableUnits().getTableUnits()) {            if (!masterSlaveRule.getName().equalsIgnoreCase(each.getDataSourceName())) {                continue;            }            toBeRemoved.add(each);            String actualDataSourceName;            if (isMasterRoute(sqlRouteResult.getSqlStatement().getType())) {                MasterVisitedManager.setMasterVisited();                actualDataSourceName = masterSlaveRule.getMasterDataSourceName();            } else {                actualDataSourceName = masterSlaveRule.getLoadBalanceAlgorithm().getDataSource(                        masterSlaveRule.getName(), masterSlaveRule.getMasterDataSourceName(), new ArrayList<>(masterSlaveRule.getSlaveDataSourceNames()));            }            toBeAdded.add(createNewTableUnit(actualDataSourceName, each));        }        sqlRouteResult.getRoutingResult().getTableUnits().getTableUnits().removeAll(toBeRemoved);        sqlRouteResult.getRoutingResult().getTableUnits().getTableUnits().addAll(toBeAdded);    }        private boolean isMasterRoute(final SQLType sqlType) {        return SQLType.DQL != sqlType || MasterVisitedManager.isMasterVisited() || HintManager.isMasterRouteOnly();    }        private TableUnit createNewTableUnit(final String actualDataSourceName, final TableUnit originalTableUnit) {        TableUnit result = new TableUnit(actualDataSourceName, originalTableUnit.getDataSourceName());        result.getRoutingTables().addAll(originalTableUnit.getRoutingTables());        return result;    }}

• ShardingMasterSlaveRouter提供了route方法，返回sqlRouteResult，这里修改了sqlRouteResult的routingResult的tableUnits的TableUnit集合

SQLRouteResult

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/SQLRouteResult.java

@RequiredArgsConstructor@Getter@Setterpublic final class SQLRouteResult {        private final SQLStatement sqlStatement;        private final GeneratedKey generatedKey;        // For multiple thread read cached sqlStatement, clone limit on SQLRouteResult, because limit will be modified after cache    // TODO need more good design here    private Limit limit;        private RoutingResult routingResult;        private OptimizeResult optimizeResult;        private final Collection routeUnits = new LinkedHashSet<>();        public SQLRouteResult(final SQLStatement sqlStatement) {        this(sqlStatement, null);    }}

• SQLRouteResult拥有RoutingResult属性

RoutingResult

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/type/RoutingResult.java

@Getterpublic class RoutingResult {        private final TableUnits tableUnits = new TableUnits();        /**     * Judge is route for single database and table only or not.     *     * @return is route for single database and table only or not     */    public boolean isSingleRouting() {        return 1 == tableUnits.getTableUnits().size();    }}

• RoutingResult拥有TableUnits属性

TableUnits

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/type/TableUnits.java

@Getter@ToStringpublic final class TableUnits {        private final Collection tableUnits = new LinkedHashSet<>();        /**     * Get all data source names.     *     * @return all data source names     */    public Collection getDataSourceNames() {        Collection result = new HashSet<>(tableUnits.size(), 1);        for (TableUnit each : tableUnits) {            result.add(each.getDataSourceName());        }        return result;    }        /**     * Get routing table via data source name and actual table name.     *     * @param dataSourceName data source name     * @param actualTableName actual table name     * @return routing table     */    public Optional getRoutingTable(final String dataSourceName, final String actualTableName) {        for (TableUnit each : tableUnits) {            Optional result = each.getRoutingTable(dataSourceName, actualTableName);            if (result.isPresent()) {                return result;            }        }        return Optional.absent();    }        /**     * Get actual tables group via data source name and logic tables' names.     * 
     * Actual tables in same group are belong one logic name.      * 
     *     * @param dataSourceName data source name     * @param logicTableNames logic tables' names     * @return actual tables group     */    public List> getActualTableNameGroups(final String dataSourceName, final Set logicTableNames) {        List> result = new ArrayList<>();        for (String logicTableName : logicTableNames) {            Set actualTableNames = getActualTableNames(dataSourceName, logicTableName);            if (!actualTableNames.isEmpty()) {                result.add(actualTableNames);            }        }        return result;    }        private Set getActualTableNames(final String dataSourceName, final String logicTableName) {        Set result = new HashSet<>(tableUnits.size(), 1);        for (TableUnit each : tableUnits) {            result.addAll(each.getActualTableNames(dataSourceName, logicTableName));        }        return result;    }        /**     * Get map relationship between data source and logic tables via data sources' names.     *     * @param dataSourceNames data sources' names     * @return  map relationship between data source and logic tables     */    public Map> getDataSourceLogicTablesMap(final Collection dataSourceNames) {        Map> result = new HashMap<>();        for (String each : dataSourceNames) {            Set logicTableNames = getLogicTableNames(each);            if (!logicTableNames.isEmpty()) {                result.put(each, logicTableNames);            }        }        return result;    }        private Set getLogicTableNames(final String dataSourceName) {        Set result = new HashSet<>(tableUnits.size(), 1);        for (TableUnit each : tableUnits) {            if (each.getDataSourceName().equalsIgnoreCase(dataSourceName)) {                result.addAll(each.getLogicTableNames(dataSourceName));            }        }        return result;    }}

• TableUnits内部是TableUnit的集合

TableUnit

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/type/TableUnit.java

@RequiredArgsConstructor@Getter@EqualsAndHashCode@ToStringpublic final class TableUnit {        private final String dataSourceName;        private final String masterSlaveLogicDataSourceName;        private final List routingTables = new LinkedList<>();        public TableUnit(final String dataSourceName) {        this.dataSourceName = dataSourceName;        masterSlaveLogicDataSourceName = dataSourceName;    }        /**     * Get routing table via data source name and actual table name.     *     * @param dataSourceName data source name     * @param actualTableName actual table name     * @return routing table     */    public Optional getRoutingTable(final String dataSourceName, final String actualTableName) {        for (RoutingTable each : routingTables) {            if (dataSourceName.equalsIgnoreCase(masterSlaveLogicDataSourceName) && each.getActualTableName().equalsIgnoreCase(actualTableName)) {                return Optional.of(each);            }        }        return Optional.absent();    }        /**     * Get actual tables' names via data source name.     *     * @param dataSourceName data source name     * @param logicTableName logic table name     * @return  actual tables' names     */    public Set getActualTableNames(final String dataSourceName, final String logicTableName) {        Set result = new HashSet<>(routingTables.size(), 1);        for (RoutingTable each : routingTables) {            if (dataSourceName.equalsIgnoreCase(this.dataSourceName) && each.getLogicTableName().equalsIgnoreCase(logicTableName)) {                result.add(each.getActualTableName());            }        }        return result;    }        /**     * Get logic tables' names via data source name.     *     * @param dataSourceName data source name     * @return  logic tables' names     */    public Set getLogicTableNames(final String dataSourceName) {        Set result = new HashSet<>(routingTables.size(), 1);        for (RoutingTable each : routingTables) {            if (dataSourceName.equalsIgnoreCase(this.dataSourceName)) {                result.add(each.getLogicTableName());            }        }        return result;    }}

• TableUnit包含了RoutingTable的集合

RoutingTable

incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/type/RoutingTable.java

@RequiredArgsConstructor@Getter@EqualsAndHashCode@ToStringpublic final class RoutingTable {        private final String logicTableName;        private final String actualTableName;}

• RoutingTable包含了logicTableName与actualTableName

小结

ShardingMasterSlaveRouter提供了route方法，返回sqlRouteResult，这里修改了sqlRouteResult的routingResult的tableUnits的TableUnit集合

以上就是怎么理解sharding-jdbc的ShardingMasterSlaveRouter，小编相信有部分知识点可能是我们日常工作会见到或用到的。希望你能通过这篇文章学到更多知识。更多详情敬请关注行业资讯频道。