springboot(十三)-分库分表-手动配置

sharding-jdbc简介

Sharding-JDBC直接封装JDBC API，可以理解为增强版的JDBC驱动，旧代码迁移成本几乎为零：
可适用于任何基于java的ORM框架，如：JPA, Hibernate, Mybatis, Spring JDBC Template或直接使用JDBC。
可基于任何第三方的数据库连接池，如：DBCP, C3P0, BoneCP, Druid等。
理论上可支持任意实现JDBC规范的数据库。虽然目前仅支持MySQL，但已有支持Oracle，SQLServer，DB2等数据库的计划。
Sharding-JDBC定位为轻量级java框架，使用客户端直连数据库，以jar包形式提供服务，未使用中间层，无需额外部署，无其他依赖，DBA也无需改变原有的运维方式。SQL解析使用Druid解析器，是目前性能最高的SQL解析器。
具体的介绍可以上它的文档那里看看，简单归纳起来就是，它是一个增强版的JDBC，对使用者透明，逻辑代码什么的都不用动，它来完成分库分表的操作；然后它还支持分布式事务（不完善）。看起来很不错的样子。
下面用个小例子来看一下分库分表的使用。使用的是SpringBoot，mybatis，DBCP连接池。

1.新建一个springboot项目

ArtifactId为sharding-jdbc-manualConfiguration.自己配置好目录结构。

2.pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.itmuch.boot</groupId>
  <artifactId>sharding-jdbc-manualConfiguration</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>sharding-jdbc-manualConfiguration</name>
  <url>http://maven.apache.org</url>

  <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!--sharding-jdbc -->
        <dependency>
            <groupId>io.shardingjdbc</groupId>
            <artifactId>sharding-jdbc-core</artifactId>
            <version>2.0.3</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
<!--         <dependency> -->
<!--             <groupId>com.alibaba</groupId> -->
<!--             <artifactId>druid</artifactId> -->
<!--             <version>1.1.3</version> -->
<!--         </dependency> -->
        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.47</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

简单提一下：

这里主要是这个依赖

　　　　 <dependency>
            <groupId>io.shardingjdbc</groupId>
            <artifactId>sharding-jdbc-core</artifactId>
            <version>2.0.3</version>
        </dependency>

它是当当网开源的sharding-jdbc，当然这个不重要啦！

顺便说一下：

<!--         <dependency> -->
<!--             <groupId>com.alibaba</groupId> -->
<!--             <artifactId>druid</artifactId> -->
<!--             <version>1.1.3</version> -->
<!--         </dependency> -->
        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
        </dependency>

我是用的DBCP数据库连接池，这里的druid连接池被我注掉了，当然你也可以使用它，把DBCP注掉。它们都差不多。我想很多其他博友应该有写。大家找找看咯！

在这里我要吐槽下：TMD，CSDN博客上面的文章叫什么东西啊，我读过几次，在上面down下来的代码都是不能运行的，然后在博客园上面再找相同内容的东西，一比对，发现很明显的配置漏洞。我也是无语了。

所以我是推荐咱博客园的文章的，大家都很优秀！！！

application.yml

我们是手动配置数据源，那这里我们可以上面都不用谢了呀！直接放个空文件得了，当然你如果不想使用8080端口，想在这里配置一下当前项目的使用端口号，你可以在这里配置下咯！！！

 数据库

我们要准备三个数据库user_0,user_1,user_2,每个数据库里准备两张表user_info_0,user_info_1.一共使用六张一样一样的表。

DROP TABLE IF EXISTS `user_info_0`;
CREATE TABLE `user_info_0` (
  `user_id` bigint(19) NOT NULL,
  `user_name` varchar(45) DEFAULT NULL,
  `account` varchar(45) DEFAULT NULL,
  `password` varchar(45) DEFAULT NULL,
  PRIMARY KEY (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Table structure for user_info_1
-- ----------------------------
DROP TABLE IF EXISTS `user_info_1`;
CREATE TABLE `user_info_1` (
  `user_id` bigint(19) NOT NULL,
  `user_name` varchar(45) DEFAULT NULL,
  `account` varchar(45) DEFAULT NULL,
  `password` varchar(45) DEFAULT NULL,
  PRIMARY KEY (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Application.java

@SpringBootApplication
@EnableAutoConfiguration(exclude = { DataSourceAutoConfiguration.class })
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

启动类嘛，我们都一样！不不不。。。注意了，多了个注解，看到它要干嘛了吗？它要把自动配置数据源的功能排除掉。

这里你要是看过我前面的文章“为什么用springboot”中的springboot自动配置的原理，这个东西，so easy啦！

 testController.java

@RestController
public class testController {
    @Resource
    UserInfoMapper userInfoMaper;

    @Resource
    DemoService demoService;

    @GetMapping("insert/{id}")
    public String insertData(@PathVariable Long id) {
        demoService.demo();
        return "success";
    }

    @GetMapping("get/{id}")
    public String getData(@PathVariable Long id) {
        UserInfo userInfoByUserId = demoService.getUserInfoByUserId(id);
        System.out.println("得到的结果为：" + JSON.toJSON(userInfoByUserId));
        return JSON.toJSON(userInfoByUserId).toString();
    }
}

对外接口，我们提供两个吧，向数据库插入数据传的id没用，我传了玩儿的！！！

插入的内容请看下面的service.

DemoService.java

@Service
public class DemoService {

    @Resource
    UserInfoMapper userInfoMapper;

    public static Long userId = 100L;

    public void demo() {
        System.out.println("Insert--------------");

        for (int i = 1; i <= 100; i++) {
            UserInfo userInfo = new UserInfo();
            userInfo.setUserId(userId);
            System.out.println(userId);

            userInfo.setAccount("Account" + i);
            userInfo.setPassword("pass" + i);
            userInfo.setUserName("name" + i);
            userId++;
            userInfoMapper.insert(userInfo);
            System.out.println("第" + i + "条");
        }
        System.out.println("over..........");
    }

    public UserInfo getUserInfoByUserId(Long id) {
        return userInfoMapper.selectByPrimaryKey(id);
    }
}

我们就试验向数据库插100条数据咯，再提供下查询方法。哦哦，Entity在下面

UserInfo.java

public class UserInfo {
    private Long userId;

    private String userName;

    private String account;

    private String password;

    public Long getUserId() {
        return userId;
    }

    public void setUserId(Long userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName == null ? null : userName.trim();
    }

    public String getAccount() {
        return account;
    }

    public void setAccount(String account) {
        this.account = account == null ? null : account.trim();
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password == null ? null : password.trim();
    }
}

UserInfoMapper.java

@Mapper
public interface UserInfoMapper {
    /**
     * This method was generated by MyBatis Generator. This method corresponds to
     * the database table user_info
     *
     * @mbg.generated Tue Mar 13 23:47:19 CST 2018
     */
    int insert(UserInfo record);

    /**
     * This method was generated by MyBatis Generator. This method corresponds to
     * the database table user_info
     *
     * @mbg.generated Tue Mar 13 23:47:19 CST 2018
     */
    int insertSelective(UserInfo record);

    /**
     * This method was generated by MyBatis Generator. This method corresponds to
     * the database table user_info
     *
     * @mbg.generated Tue Mar 13 23:47:19 CST 2018
     */
    UserInfo selectByPrimaryKey(Long userId);

    /**
     * This method was generated by MyBatis Generator. This method corresponds to
     * the database table user_info
     *
     * @mbg.generated Tue Mar 13 23:47:19 CST 2018
     */
    int updateByPrimaryKeySelective(UserInfo record);

    /**
     * This method was generated by MyBatis Generator. This method corresponds to
     * the database table user_info
     *
     * @mbg.generated Tue Mar 13 23:47:19 CST 2018
     */
    int updateByPrimaryKey(UserInfo record);
}

因为是用mybatis的逆向工程自动生成的，东西多余了点。懒得删了。但是注意下，类名上面的@Mapper注解是我加的。

这里我展开说一下，我在网上看到很多人在springboot项目中使用Mybatis作为持久层框架的时候，都不这么用。都是在resource根目录下面建一个文件夹mapper,然后把所有的XXXMapper.xml文件放到里面，XXXMapper.java还是放到com...mapper中不变。然后在启动类上面添加一个针对这个com...mapper文件夹的@ComponentScan(“com...mapper”)注解。还要在根目录resource下面配置mybatis-config.xml文件。更有甚者，居然有人在application.properties文件或application.yml文件中配置mybatis的东西，例如：

mybatis:

  mapper-locations: classpath:mybatis/mapper/*.xml

  type-aliases-package: com.sun.shard.bean

虽然springboot也能支持这样使用，但是我是不建议也不喜欢这样的风格，因为你想啊，我们为什么要用springboot?不就是想尽量少写点配置嘛，把这些繁琐的东西交给springboot来做就得了！要不然springboot出mybatis-spring-boot-starter这个启动器干啥！

对了，大家想了解为啥，建议大家自己看下源码，你加了mybatis-spring-boot-starter这个依赖，在Maven Dependencies下面找到

看明白这个类，基本就没啥东西了。

 扯远了，我们继续我们的分库分表。

UserInfoMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itmuch.boot.mapper.UserInfoMapper">
  <resultMap id="BaseResultMap" type="com.itmuch.boot.entity.UserInfo">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Tue Mar 13 23:47:19 CST 2018.
    -->
    <id column="user_id" jdbcType="BIGINT" property="userId" />
    <result column="user_name" jdbcType="VARCHAR" property="userName" />
    <result column="account" jdbcType="VARCHAR" property="account" />
    <result column="password" jdbcType="VARCHAR" property="password" />
  </resultMap>
  <sql id="Base_Column_List">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Tue Mar 13 23:47:19 CST 2018.
    -->
    user_id, user_name, account, password
  </sql>
  <select id="selectByPrimaryKey" parameterType="java.lang.Long" resultMap="BaseResultMap">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Tue Mar 13 23:47:19 CST 2018.
    -->
    select 
    <include refid="Base_Column_List" />
    from user_info
    where user_id = #{userId,jdbcType=BIGINT}
  </select>
  <insert id="insert" parameterType="com.itmuch.boot.entity.UserInfo">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Tue Mar 13 23:47:19 CST 2018.
    -->
    insert into user_info (user_id, user_name, account, 
      password)
    values (#{userId,jdbcType=BIGINT}, #{userName,jdbcType=VARCHAR}, #{account,jdbcType=VARCHAR}, 
      #{password,jdbcType=VARCHAR})
  </insert>
  <insert id="insertSelective" parameterType="com.itmuch.boot.entity.UserInfo">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Tue Mar 13 23:47:19 CST 2018.
    -->
    insert into user_info
    <trim prefix="(" suffix=")" suffixOverrides=",">
      <if test="userId != null">
        user_id,
      </if>
      <if test="userName != null">
        user_name,
      </if>
      <if test="account != null">
        account,
      </if>
      <if test="password != null">
        password,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides=",">
      <if test="userId != null">
        #{userId,jdbcType=BIGINT},
      </if>
      <if test="userName != null">
        #{userName,jdbcType=VARCHAR},
      </if>
      <if test="account != null">
        #{account,jdbcType=VARCHAR},
      </if>
      <if test="password != null">
        #{password,jdbcType=VARCHAR},
      </if>
    </trim>
  </insert>
  <update id="updateByPrimaryKeySelective" parameterType="com.itmuch.boot.entity.UserInfo">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Tue Mar 13 23:47:19 CST 2018.
    -->
    update user_info
    <set>
      <if test="userName != null">
        user_name = #{userName,jdbcType=VARCHAR},
      </if>
      <if test="account != null">
        account = #{account,jdbcType=VARCHAR},
      </if>
      <if test="password != null">
        password = #{password,jdbcType=VARCHAR},
      </if>
    </set>
    where user_id = #{userId,jdbcType=BIGINT}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.itmuch.boot.entity.UserInfo">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Tue Mar 13 23:47:19 CST 2018.
    -->
    update user_info
    set user_name = #{userName,jdbcType=VARCHAR},
      account = #{account,jdbcType=VARCHAR},
      password = #{password,jdbcType=VARCHAR}
    where user_id = #{userId,jdbcType=BIGINT}
  </update>
</mapper>

 到这里我们一套流程算是下来了。接下来是重点，手动添加数据源配置。

DataSourceConfig.java

@Configuration
@MapperScan(basePackages = "com.itmuch.boot.mapper")
public class DataSourceConfig {

    @Bean(name = "shardingDataSource")
    DataSource getShardingDataSource() throws SQLException {
        ShardingRuleConfiguration shardingRuleConfig;
        shardingRuleConfig = new ShardingRuleConfiguration();
        shardingRuleConfig.getTableRuleConfigs().add(getUserTableRuleConfiguration());
        shardingRuleConfig.getBindingTableGroups().add("user_info");
        shardingRuleConfig.setDefaultDatabaseShardingStrategyConfig(
                new StandardShardingStrategyConfiguration("user_id", DemoDatabaseShardingAlgorithm.class.getName()));
        shardingRuleConfig.setDefaultTableShardingStrategyConfig(
                new StandardShardingStrategyConfiguration("user_id", DemoTableShardingAlgorithm.class.getName()));
        return new ShardingDataSource(shardingRuleConfig.build(createDataSourceMap()));
    }

    @Bean
    TableRuleConfiguration getUserTableRuleConfiguration() {
        TableRuleConfiguration orderTableRuleConfig = new TableRuleConfiguration();
        orderTableRuleConfig.setLogicTable("user_info");
        orderTableRuleConfig.setActualDataNodes("user_${0..2}.user_info_${0..1}");
        orderTableRuleConfig.setKeyGeneratorColumnName("user_id");
        return orderTableRuleConfig;
    }

    private Map<String, DataSource> createDataSourceMap() {
        Map<String, DataSource> result = new HashMap<>();
        result.put("user_0", createDataSource("user_0"));
        result.put("user_1", createDataSource("user_1"));
        result.put("user_2", createDataSource("user_2"));
        return result;
    }

    private DataSource createDataSource(final String dataSourceName) {
        BasicDataSource result = new BasicDataSource();
        result.setDriverClassName(com.mysql.jdbc.Driver.class.getName());
        result.setUrl(String.format("jdbc:mysql://localhost:3306/%s", dataSourceName));

        result.setUsername("root");
        result.setPassword("root");
        return result;
    }

}

 这个数据源配置类大家也看到了，并不复杂，你看啊，我们准备了三个数据库user_0,user_1,user_2；每个数据中准备了两张相同的业务表user_info_0和user_info_1.带着这个信息去看这个类，不用多说。

DemoDatabaseShardingAlgorithm.java

public class DemoDatabaseShardingAlgorithm implements PreciseShardingAlgorithm<Long> {
    @Override
    public String doSharding(Collection<String> collection, PreciseShardingValue<Long> preciseShardingValue) {
        for (String each : collection) {
            if (each.endsWith(Long.parseLong(preciseShardingValue.getValue().toString()) % 3 + "")) {
                return each;
            }
        }
        throw new IllegalArgumentException();
    }
}

 顾名思义，这是分库算法，根据选择的字段（上面DataSourceConfig.java第12行我们选的字段是user_id）对3取余。

 DemoTableShardingAlgorithm.java

public class DemoTableShardingAlgorithm implements PreciseShardingAlgorithm<Long> {
    @Override
    public String doSharding(Collection<String> collection, PreciseShardingValue<Long> preciseShardingValue) {
        for (String each : collection) {
            if (each.endsWith(Long.parseLong(preciseShardingValue.getValue().toString()) % 2 + "")) {
                return each;
            }
        }
        throw new IllegalArgumentException();
    }
}

 顾名思义，这是分表算法，根据选择的字段（上面DataSourceConfig.java第14行我们选的字段也是user_id）对2取余。

测试

代码就这么多，启动application.java类，我们访问localhost:8080/insert/1试试。

然后看数据库：我们之前建的三个库，共六张表，四张表都是17条记录，两张表里面分别有16条，一共100条。根据user_id判断，没有重复的，那基本哦了呀！

---

代码地址：https://gitee.com/fengyuduke/my_open_resources/blob/master/sharding-jdbc-manualConfiguration.rar