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();
}
}
点击展开
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>
点击展开
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