simplify quick start

```

### 规则配置

Sharding-JDBC的分库分表通过规则配置描述，请简单浏览配置全貌：

```java

    // 配置真实数据源

    Map<String, DataSource> dataSourceMap = new HashMap<>();

    // 配置第一个数据源

    BasicDataSource dataSource1 = new BasicDataSource();

    dataSource1.setDriverClassName("com.mysql.jdbc.Driver");

    dataSource1.setUrl("jdbc:mysql://localhost:3306/ds_0");

    dataSource1.setUsername("root");

    dataSource1.setPassword("");

    dataSourceMap.put("ds_0", dataSource1);

    // 配置第二个数据源

    BasicDataSource dataSource2 = new BasicDataSource();

    dataSource2.setDriverClassName("com.mysql.jdbc.Driver");

    dataSource2.setUrl("jdbc:mysql://localhost:3306/ds_1");

    dataSource2.setUsername("root");

    dataSource2.setPassword("");

    dataSourceMap.put("ds_1", dataSource2);

    // 配置Order表规则

    TableRuleConfiguration orderTableRuleConfig = new TableRuleConfiguration();

    orderTableRuleConfig.setLogicTable("t_order");

    orderTableRuleConfig.setActualDataNodes("ds_${0..1}.t_order_${[0, 1]}");

    // 配置分库策略

    orderTableRuleConfig.setDatabaseShardingStrategyConfig(new InlineShardingStrategyConfiguration("user_id", "ds_${user_id % 2}"));

    // 配置分表策略

    orderTableRuleConfig.setTableShardingStrategyConfig(new InlineShardingStrategyConfiguration("order_id", "t_order_${order_id % 2}"));

    // 配置分片规则

    ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();

    shardingRuleConfig.getTableRuleConfigs().add(orderTableRuleConfig);

    // 省略配置order_item表规则...

    // 获取数据源对象

    DataSource dataSource = ShardingDataSourceFactory.createDataSource(dataSourceMap, shardingRuleConfig);

```

或通过YAML方式配置，与以上配置等价：

```yaml

dataSources:

  ds_0: !!org.apache.commons.dbcp.BasicDataSource

    driverClassName: com.mysql.jdbc.Driver

    url: jdbc:mysql://localhost:3306/ds_0

    username: root

    password: 

  ds_1: !!org.apache.commons.dbcp.BasicDataSource

    driverClassName: com.mysql.jdbc.Driver

    url: jdbc:mysql://localhost:3306/ds_1

    username: root

    password: 

shardingRule:

  tables:

    t_order: 

      actualDataNodes: ds_${0..1}.t_order_${0..1}

      databaseStrategy: 

        inline:

          shardingColumn: user_id

          algorithmExpression: ds_${user_id % 2}

      tableStrategy: 

        inline:

          shardingColumn: order_id

          algorithmExpression: t_order_${order_id % 2}

    t_order_item: 

      actualDataNodes: ds_${0..1}.t_order_item_${0..1}

      databaseStrategy: 

        inline:

          shardingColumn: user_id

          algorithmExpression: ds_${user_id % 2}

      tableStrategy: 

        inline:

          shardingColumn: order_id

          algorithmExpression: t_order_item_${order_id % 2}  

```

```java

    DataSource dataSource = ShardingDataSourceFactory.createDataSource(yamlFile);

```

Sharding-JDBC可以通过Java，YAML，Spring命名空间和Spring Boot Starter四种方式配置，开发者可根据场景选择适合的配置方式。

规则配置包括数据源配置、表规则配置、分库策略和分表策略组成。这只是最简单的配置方式，实际使用可更加灵活，如：多分片键，分片策略直接和表规则配置绑定等。

### 创建DataSource

### 使用原生JDBC接口

通过ShardingDataSourceFactory工厂和规则配置对象获取ShardingDataSource，ShardingDataSource实现自JDBC的标准接口DataSource。然后可通过DataSource选择使用原生JDBC开发，或者使用JPA, MyBatis等ORM工具。

以JDBC原生实现为例：

通过ShardingDataSourceFactory工厂和规则配置对象获取ShardingDataSource，ShardingDataSource实现自JDBC的标准接口DataSource。然后即可通过DataSource选择使用原生JDBC开发，或者使用JPA, MyBatis等ORM工具。

```java

DataSource dataSource = ShardingDataSourceFactory.createDataSource(dataSourceMap, shardingRuleConfig);

String sql = "SELECT i.* FROM t_order o JOIN t_order_item i ON o.order_id=i.order_id WHERE o.user_id=? AND o.order_id=?";

try (

        Connection conn = dataSource.getConnection();

        PreparedStatement preparedStatement = conn.prepareStatement(sql)) {

    preparedStatement.setInt(1, 10);

    preparedStatement.setInt(2, 1001);

    try (ResultSet rs = preparedStatement.executeQuery()) {

        while(rs.next()) {

            System.out.println(rs.getInt(1));

            System.out.println(rs.getInt(2));

        }

    }

}

```

### 使用Spring命名空间配置

```xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 

    xmlns:context="http://www.springframework.org/schema/context"

    xmlns:sharding="http://shardingjdbc.io/schema/shardingjdbc/sharding" 

    xsi:schemaLocation="http://www.springframework.org/schema/beans 

                        http://www.springframework.org/schema/beans/spring-beans.xsd

                        http://www.springframework.org/schema/context 

                        http://www.springframework.org/schema/context/spring-context.xsd 

                        http://shardingjdbc.io/schema/shardingjdbc/sharding 

                        http://shardingjdbc.io/schema/shardingjdbc/sharding/sharding.xsd 

                        ">

    <context:property-placeholder location="classpath:conf/conf.properties" ignore-unresolvable="true" />

    <bean id="ds_0" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

        <property name="driverClassName" value="com.mysql.jdbc.Driver" />

        <property name="url" value="jdbc:mysql://localhost:3306/ds_0" />

        <property name="username" value="root" />

        <property name="password" value="" />

    </bean>

    <bean id="ds_1" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

        <property name="driverClassName" value="com.mysql.jdbc.Driver" />

        <property name="url" value="jdbc:mysql://localhost:3306/ds_1" />

        <property name="username" value="root" />

        <property name="password" value="" />

    </bean>

    <sharding:inline-strategy id="databaseStrategy" sharding-column="user_id" algorithm-expression="ds_${user_id % 2}" />

    <sharding:inline-strategy id="orderTableStrategy" sharding-column="order_id" algorithm-expression="t_order_${order_id % 2}" />

    <sharding:inline-strategy id="orderItemTableStrategy" sharding-column="order_id" algorithm-expression="t_order_item_${order_id % 2}" />

    <sharding:data-source id="shardingDataSource">

        <sharding:sharding-rule data-source-names="ds_0,ds_1">

            <sharding:table-rules>

                <sharding:table-rule logic-table="t_order" actual-data-nodes="ds_${0..1}.t_order_${0..1}" database-strategy-ref="databaseStrategy" table-strategy-ref="orderTableStrategy" />

                <sharding:table-rule logic-table="t_order_item" actual-data-nodes="ds_${0..1}.t_order_item_${0..1}" database-strategy-ref="databaseStrategy" table-strategy-ref="orderItemTableStrategy" />

            </sharding:table-rules>

        </sharding:sharding-rule>

    </sharding:data-source>

</beans>

```

## Sharding-JDBC-Server