sharding-jdbc如何配置分析Configuration

發(fā)布時間：2021-10-20 16:51:28 來源：億速云閱讀：158 作者：柒染欄目：大數(shù)據(jù)

sharding-jdbc如何配置分析Configuration，很多新手對此不是很清楚，為了幫助大家解決這個難題，下面小編將為大家詳細(xì)講解，有這方面需求的人可以來學(xué)習(xí)下，希望你能有所收獲。

Sharding核心配置主要如下（官網(wǎng)）：

分片規(guī)則
分片規(guī)則配置的總?cè)肟凇０瑪?shù)據(jù)源配置、表配置、綁定表配置以及讀寫分離配置等
數(shù)據(jù)源配置
真實數(shù)據(jù)源列表
表配置
邏輯表名稱、數(shù)據(jù)節(jié)點與分表規(guī)則的配置
數(shù)據(jù)節(jié)點配置
用于配置邏輯表與真實表的映射關(guān)系。可分為均勻分布和自定義分布兩種形式
分片策略配置
對于分片策略存有數(shù)據(jù)源分片策略和表分片策略兩種維度

數(shù)據(jù)源分片策略：
對應(yīng)于DatabaseShardingStrategy。用于配置數(shù)據(jù)被分配的目標(biāo)數(shù)據(jù)源
表分片策略
對應(yīng)于TableShardingStrategy。用于配置數(shù)據(jù)被分配的目標(biāo)表，該目標(biāo)表存在與該數(shù)據(jù)的目標(biāo)數(shù)據(jù)源內(nèi)。故表分片策略是依賴與數(shù)據(jù)源分片策略的結(jié)果的

自增主鍵生成策略
通過在客戶端生成自增主鍵替換以數(shù)據(jù)庫原生自增主鍵的方式，做到分布式主鍵無重復(fù)。

接下來對各個核心配置進行分析：

以多主多從讀寫分離、表分片為例

public final class ShardingMasterSlaveConfigurationPrecise implements ExampleConfiguration {
    
    @Override
    public DataSource getDataSource() throws SQLException {
        ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
        //分片表規(guī)則配置
        shardingRuleConfig.getTableRuleConfigs().add(getOrderTableRuleConfiguration());
        shardingRuleConfig.getTableRuleConfigs().add(getOrderItemTableRuleConfiguration());
        //綁定分片表，主要用來路由
        shardingRuleConfig.getBindingTableGroups().add("t_order, t_order_item");
        //設(shè)置默認(rèn)數(shù)據(jù)源分片策略
        shardingRuleConfig.setDefaultDatabaseShardingStrategyConfig(new StandardShardingStrategyConfiguration("user_id", new PreciseModuloShardingDatabaseAlgorithm()));
        //設(shè)置默認(rèn)表分片策略
        shardingRuleConfig.setDefaultTableShardingStrategyConfig(new StandardShardingStrategyConfiguration("order_id", new PreciseModuloShardingTableAlgorithm()));
        //主從配置，支持多主多從
        shardingRuleConfig.setMasterSlaveRuleConfigs(getMasterSlaveRuleConfigurations());
        //創(chuàng)建ShardingDataSource數(shù)據(jù)源
        return ShardingDataSourceFactory.createDataSource(createDataSourceMap(), shardingRuleConfig, new Properties());
    }
    
    private static TableRuleConfiguration getOrderTableRuleConfiguration() {
        //分片表配置
        TableRuleConfiguration result = new TableRuleConfiguration(/*邏輯表*/"t_order", /*數(shù)據(jù)源名.真實表*/"ds_${0..1}.t_order_${[0, 1]}");
        //自定義主鍵生成配置
        result.setKeyGeneratorConfig(new KeyGeneratorConfiguration("SNOWFLAKE", "order_id", getProperties()));
        return result;
    }
    
    private static TableRuleConfiguration getOrderItemTableRuleConfiguration() {
        TableRuleConfiguration result = new TableRuleConfiguration("t_order_item", "ds_${0..1}.t_order_item_${[0, 1]}");
        result.setKeyGeneratorConfig(new KeyGeneratorConfiguration("SNOWFLAKE", "order_item_id", getProperties()));
        return result;
    }
    
    private static List<MasterSlaveRuleConfiguration> getMasterSlaveRuleConfigurations() {
        MasterSlaveRuleConfiguration masterSlaveRuleConfig1 = new MasterSlaveRuleConfiguration("ds_0", "demo_ds_master_0", Arrays.asList("demo_ds_master_0_slave_0", "demo_ds_master_0_slave_1"));
        MasterSlaveRuleConfiguration masterSlaveRuleConfig2 = new MasterSlaveRuleConfiguration("ds_1", "demo_ds_master_1", Arrays.asList("demo_ds_master_1_slave_0", "demo_ds_master_1_slave_1"));
        return Lists.newArrayList(masterSlaveRuleConfig1, masterSlaveRuleConfig2);
    }
    
    private static Map<String, DataSource> createDataSourceMap() {
        final Map<String, DataSource> result = new HashMap<>();
        result.put("demo_ds_master_0", DataSourceUtil.createDataSource("demo_ds_master_0"));
        result.put("demo_ds_master_0_slave_0", DataSourceUtil.createDataSource("demo_ds_master_0_slave_0"));
        result.put("demo_ds_master_0_slave_1", DataSourceUtil.createDataSource("demo_ds_master_0_slave_1"));
        result.put("demo_ds_master_1", DataSourceUtil.createDataSource("demo_ds_master_1"));
        result.put("demo_ds_master_1_slave_0", DataSourceUtil.createDataSource("demo_ds_master_1_slave_0"));
        result.put("demo_ds_master_1_slave_1", DataSourceUtil.createDataSource("demo_ds_master_1_slave_1"));
        return result;
    }
    
    private static Properties getProperties() {
        Properties result = new Properties();
        result.setProperty("worker.id", "123");
        return result;
    }
}

ShardingRuleConfiguration分片規(guī)則核心配置

@Getter
@Setter
public final class ShardingRuleConfiguration implements RuleConfiguration {
    //表規(guī)則配置
    private Collection<TableRuleConfiguration> tableRuleConfigs = new LinkedList<>();

    //綁定表配置
    private Collection<String> bindingTableGroups = new LinkedList<>();

    //廣播表配置
    private Collection<String> broadcastTables = new LinkedList<>();

    //默認(rèn)數(shù)據(jù)源名稱
    private String defaultDataSourceName;

    //默認(rèn)分庫策略
    private ShardingStrategyConfiguration defaultDatabaseShardingStrategyConfig;

    //默認(rèn)分片策略
    private ShardingStrategyConfiguration defaultTableShardingStrategyConfig;

    //默認(rèn)主鍵生成工具類
    private KeyGeneratorConfiguration defaultKeyGeneratorConfig;

    //主從規(guī)則配置
    private Collection<MasterSlaveRuleConfiguration> masterSlaveRuleConfigs = new LinkedList<>();

    //數(shù)據(jù)脫敏規(guī)則配置
    private EncryptRuleConfiguration encryptRuleConfig;
}

分析ShardingDataSourceFactory#createDataSource中的ShardingRule配置

/**
 * Sharding data source factory.
 * 
 * @author zhangliang 
 */
@NoArgsConstructor(access = AccessLevel.PRIVATE)
public final class ShardingDataSourceFactory {
    
    /**
     * Create sharding data source.
     *
     * @param dataSourceMap data source map
     * @param shardingRuleConfig rule configuration for databases and tables sharding
     * @param props properties for data source
     * @return sharding data source
     * @throws SQLException SQL exception
     */
    public static DataSource createDataSource(
            final Map<String, DataSource> dataSourceMap, final ShardingRuleConfiguration shardingRuleConfig, final Properties props) throws SQLException {
        //創(chuàng)建ShardingDataSource數(shù)據(jù)源，同時創(chuàng)建sharding rule配置
        return new ShardingDataSource(dataSourceMap, new ShardingRule(shardingRuleConfig, dataSourceMap.keySet()), props);
    }
}

ShardingRule分片規(guī)則

public ShardingRule(final ShardingRuleConfiguration shardingRuleConfig, final Collection<String> dataSourceNames) {
        Preconditions.checkArgument(null != shardingRuleConfig, "ShardingRuleConfig cannot be null.");
        Preconditions.checkArgument(null != dataSourceNames && !dataSourceNames.isEmpty(), "Data sources cannot be empty.");
        this.shardingRuleConfig = shardingRuleConfig;
        //sharding數(shù)據(jù)源名稱
        shardingDataSourceNames = new ShardingDataSourceNames(shardingRuleConfig, dataSourceNames);
        //創(chuàng)建表規(guī)則集合
        tableRules = createTableRules(shardingRuleConfig);
        //創(chuàng)建分組綁定表
        //1.從tableRules查找
        //2.是否廣播表，如果是廣播表，dataSourceNames.size() == 1 ? dataSourceNames.iterator().next() : shardingRuleConfig.getDefaultDataSourceName();
        //3.已上兩種情況都不滿足，則使用默認(rèn)數(shù)據(jù)源創(chuàng)建tableRule
        bindingTableRules = createBindingTableRules(shardingRuleConfig.getBindingTableGroups());
        //廣播表
        broadcastTables = shardingRuleConfig.getBroadcastTables();
        //默認(rèn)分庫策略
        defaultDatabaseShardingStrategy = createDefaultShardingStrategy(shardingRuleConfig.getDefaultDatabaseShardingStrategyConfig());
        //默認(rèn)表分片策略
        defaultTableShardingStrategy = createDefaultShardingStrategy(shardingRuleConfig.getDefaultTableShardingStrategyConfig());
        //默認(rèn)主鍵生成工具類
        defaultShardingKeyGenerator = createDefaultKeyGenerator(shardingRuleConfig.getDefaultKeyGeneratorConfig());
        //創(chuàng)建主從規(guī)則
        masterSlaveRules = createMasterSlaveRules(shardingRuleConfig.getMasterSlaveRuleConfigs());
        //數(shù)據(jù)脫敏規(guī)則
        encryptRule = createEncryptRule(shardingRuleConfig.getEncryptRuleConfig());
    }

TableRule表規(guī)則

public TableRule(final TableRuleConfiguration tableRuleConfig, final ShardingDataSourceNames shardingDataSourceNames, final String defaultGenerateKeyColumn) {
        //獲取邏輯表
        logicTable = tableRuleConfig.getLogicTable().toLowerCase();
        //inline表達式解析出真實表，比如：ds_${0..1}.t_order_${[0, 1]}
        //解析出來為：
        //ds_0.t_order_0
        //ds_0.t_order_1
        //ds_1.t_order_0
        //ds_1.t_order_1
        List<String> dataNodes = new InlineExpressionParser(tableRuleConfig.getActualDataNodes()).splitAndEvaluate();

        dataNodeIndexMap = new HashMap<>(dataNodes.size(), 1);

        //真實表數(shù)據(jù)節(jié)點
        //1.如果沒有配置真實表，則根據(jù)邏輯表、數(shù)據(jù)源來生成對應(yīng)真實表數(shù)據(jù)節(jié)點
        //2.否則根據(jù)inline表達式解析出來的真實表來生成真實數(shù)據(jù)節(jié)點
        actualDataNodes = isEmptyDataNodes(dataNodes)
            ? generateDataNodes(tableRuleConfig.getLogicTable(), shardingDataSourceNames.getDataSourceNames()) : generateDataNodes(dataNodes, shardingDataSourceNames.getDataSourceNames());
        //真實表
        actualTables = getActualTables();
        //數(shù)據(jù)源->分片策略
        databaseShardingStrategy = null == tableRuleConfig.getDatabaseShardingStrategyConfig() ? null : ShardingStrategyFactory.newInstance(tableRuleConfig.getDatabaseShardingStrategyConfig());
        //表->分片策略
        tableShardingStrategy = null == tableRuleConfig.getTableShardingStrategyConfig() ? null : ShardingStrategyFactory.newInstance(tableRuleConfig.getTableShardingStrategyConfig());
        //主鍵字段
        generateKeyColumn = getGenerateKeyColumn(tableRuleConfig.getKeyGeneratorConfig(), defaultGenerateKeyColumn);
        //生成主鍵工具類，比如SNOWFLAKE
        shardingKeyGenerator = containsKeyGeneratorConfiguration(tableRuleConfig)
                ? new ShardingKeyGeneratorServiceLoader().newService(tableRuleConfig.getKeyGeneratorConfig().getType(), tableRuleConfig.getKeyGeneratorConfig().getProperties()) : null;
    }

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