Java中ShardingSphere 数据分片的实现
目录
- 前言
- ShardingSphere介绍
- 为什么不用mycat
- 实践前的准备工作
- 代码案例
前言
其实很多人对分库分表多少都有点恐惧，其实我也是，总觉得这玩意是运维干的、数据量上来了或者sql过于复杂、一些数据分片的中间件支持的也不是很友好、配置繁琐等多种问题。
我们今天用ShardingSphere 给大家演示数据分片，包括分库分表、只分表不分库进行说明。
下一节有时间的话在讲讲读写分离吧。
github地址：https://github.com/362460453/boot-sharding-JDBC
ShardingSphere介绍
ShardingSphere是一套开源的分布式数据库中间件解决方案组成的生态圈，它由Sharding-JDBC、Sharding-Proxy和Sharding-Sidecar（计划中）这3款相互独立的产品组成。 他们均提供标准化的数据分片、分布式事务和数据库治理功能，可适用于如Java同构、异构语言、容器、云原生等各种多样化的应用场景。
ShardingSphere的功能能帮助我们做什么
- 数据分片
- 读写分离
- 编排治理
- 分布式事务
2016年初Sharding-JDBC被开源，这个产品是当当的，加入了Apache 后改名为 ShardingSphere 。他是我们应用和数据库之间的中间层，虽代码入侵性很强，但不会对现有业务逻辑进行改变。
更多文档请点击官网：https://shardingsphere.apache.org/document/current/en/overview/
为什么不用mycat
大家如果去查相关资料会知道，mycat和ShardingSphere是同类型的中间件，主要的功能，数据分片和读写分离两个都能去做，但是姿势却有很大的差别， 从字面意义上看Sharding 含义是分片、碎片的意思，所以不难理解ShardingSphere 对数据分片有很强对能力，对于99%对sql都是支持的，官网也有sql支持的相关内容，大家详细阅读，只有 类似sum 这种函数不支持，而且对 ORM框架和常用数据库基本都兼容，所以个人建议如果你们做数据分片，也就是是分库分表对话，强烈建议选择ShardingSphere，因为我私下也和一些朋友交流过，mycat 的数据分片对多表查询不是很友好，而且用 mycat 要有很强的运维来做，还有一点就是mycat 都是靠xml配置的，没有代码入侵，所以这也算是他的优点吧。如果你们只做读写分离对话，那么我建议用mycat，是没问题的。
实践前的准备工作
启动你的mysql，创建两个数据库，分别叫 sharding_master 和 sharding_salve分别在这两个数据库执行如下sql
CREATE TABLE IF NOT EXISTS `t_order_0` ( `order_id` INT NOT NULL, `user_id` INT NOT NULL, PRIMARY KEY (`order_id`) ); CREATE TABLE IF NOT EXISTS `t_order_1` ( `order_id` INT NOT NULL, `user_id` INT NOT NULL, PRIMARY KEY (`order_id`) );
做完以上两步结果如下
代码案例
环境
1.8.0_144
创建一个springboot工程，我们使用 JdbcTemplate 框架，如果用mybatis也是无影响的。
pom引用依赖如下
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.4.RELEASE</version>
</parent>
<properties>
<java.version>1.8</java.version>
<druid.version>1.0.26</druid.version>
<sharding.jdbc.core.version>1.3.3</sharding.jdbc.core.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>com.dangdang</groupId>
<artifactId>sharding-jdbc-core</artifactId>
<version>${sharding.jdbc.core.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>${druid.version}</version>
</dependency>
</dependencies>
application.yml 配置如下
server:
port: 8050
sharding:
jdbc:
driverClassName: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/sharding_master?useUnicode=true&characterEncoding=UTF-8&autoReconnect=true&failOverReadOnly=false
username: root
password: 123456
filters: stat
maxActive: 100
initialSize: 1
maxWait: 15000
minIdle: 1
timeBetweenEvictionRunsMillis: 30000
minEvictableIdleTimeMillis: 180000
validationQuery: SELECT 'x'
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
poolPreparedStatements: false
maxPoolPreparedStatementPerConnectionSize: 20
removeAbandoned: true
removeAbandonedTimeout: 600
logAbandoned: false
connectionInitSqls:
url0: jdbc:mysql://localhost:3306/sharding_master?useUnicode=true&characterEncoding=UTF-8&autoReconnect=true&failOverReadOnly=false
username0: root
password0: 123456
url1: jdbc:mysql://localhost:3306/sharding_salve?useUnicode=true&characterEncoding=UTF-8&autoReconnect=true&failOverReadOnly=false
username1: root
password1: 123456
yml映射成Bean
@Data
@ConfigurationProperties(prefix="sharding.jdbc")
public class ShardDataSourceProperties {
private String driverClassName;
private String url;
private String username;
private String password;
private String url0;
private String username0;
private String password0;
private String url1;
private String username1;
private String password1;
private String filters;
private int maxActive;
private int initialSize;
private int maxWait;
private int minIdle;
private int timeBetweenEvictionRunsMillis;
private int minEvictableIdleTimeMillis;
private String validationQuery;
private boolean testWhileIdle;
private boolean testOnBorrow;
private boolean testOnReturn;
private boolean poolPreparedStatements;
private int maxPoolPreparedStatementPerConnectionSize;
private boolean removeAbandoned;
private int removeAbandonedTimeout;
private boolean logAbandoned;
private List<String> connectionInitSqls;
//省略geter setter
分库策略
//通过实现SingleKeyDatabaseShardingAlgorithm接口实现分库
public class ModuloDatabaseShardingAlgorithm implements SingleKeyDatabaseShardingAlgorithm<Integer> {
@Override
public String doEqualSharding(Collection<String> availableTargetNames, ShardingValue<Integer> shardingValue) {
for (String each : availableTargetNames) {
if (each.endsWith(shardingValue.getValue() % 2 + "")) {
return each;
}
}
throw new IllegalArgumentException();
}
@Override
public Collection<String> doInSharding(Collection<String> availableTargetNames,
ShardingValue<Integer> shardingValue) {
Collection<String> result = new LinkedHashSet<>(availableTargetNames.size());
for (Integer value : shardingValue.getValues()) {
for (String targetName : availableTargetNames) {
if (targetName.endsWith(value % 2 + "")) {
result.add(targetName);
}
}
}
return result;
}
@Override
public Collection<String> doBetweenSharding(Collection<String> availableTargetNames,
ShardingValue<Integer> shardingValue) {
Collection<String> result = new LinkedHashSet<>(availableTargetNames.size());
Range<Integer> range = (Range<Integer>) shardingValue.getValueRange();
for (Integer i = range.lowerEndpoint(); i <= range.upperEndpoint(); i++) {
for (String each : availableTargetNames) {
if (each.endsWith(i % 2 + "")) {
result.add(each);
}
}
}
return result;
}
}
分表策略
public class ModuloTableShardingAlgorithm implements SingleKeyTableShardingAlgorithm<Integer> {
/**
* 对于分片字段的等值操作 都走这个方法。(包括 插入 更新)
* 如：
* <p>
* select * from t_order from t_order where order_id = 11
* └── SELECT * FROM t_order_1 WHERE order_id = 11
* select * from t_order from t_order where order_id = 44
* └── SELECT * FROM t_order_0 WHERE order_id = 44
* </P>
*/
@Override
public String doEqualSharding(final Collection<String> tableNames, final ShardingValue<Integer> shardingValue) {
for (String each : tableNames) {
if (each.endsWith(shardingValue.getValue() % 2 + "")) {
return each;
}
}
throw new IllegalArgumentException();
}
/**
* 对于分片字段的in操作，都走这个方法。
* select * from t_order from t_order where order_id in (11,44)
* ├── SELECT * FROM t_order_0 WHERE order_id IN (11,44)
* └── SELECT * FROM t_order_1 WHERE order_id IN (11,44)
* select * from t_order from t_order where order_id in (11,13,15)
* └── SELECT * FROM t_order_1 WHERE order_id IN (11,13,15)
* select * from t_order from t_order where order_id in (22,24,26)
* └──SELECT * FROM t_order_0 WHERE order_id IN (22,24,26)
*/
@Override
public Collection<String> doInSharding(final Collection<String> tableNames, final ShardingValue<Integer> shardingValue) {
Collection<String> result = new LinkedHashSet<>(tableNames.size());
for (Integer value : shardingValue.getValues()) {
for (String tableName : tableNames) {
if (tableName.endsWith(value % 2 + "")) {
result.add(tableName);
}
}
}
return result;
}
/**
* 对于分片字段的between操作都走这个方法。
* select * from t_order from t_order where order_id between 10 and 20
* ├── SELECT * FROM t_order_0 WHERE order_id BETWEEN 10 AND 20
* └── SELECT * FROM t_order_1 WHERE order_id BETWEEN 10 AND 20
*/
@Override
public Collection<String> doBetweenSharding(final Collection<String> tableNames, final ShardingValue<Integer> shardingValue) {
Collection<String> result = new LinkedHashSet<>(tableNames.size());
Range<Integer> range = (Range<Integer>) shardingValue.getValueRange();
for (Integer i = range.lowerEndpoint(); i <= range.upperEndpoint(); i++) {
for (String each : tableNames) {
if (each.endsWith(i % 2 + "")) {
result.add(each);
}
}
}
return result;
}
}
对特定表和库，进行特定的分库分表规则
简单说，就是分库按照了user_id的奇偶区分，分表按照order_id 的奇偶区分，
如果你有多个表进行分片，就写多个TableRule，
配置两个数据源，分别是我在yml里的配置，根据你的需求个性化配置就可以。
@Configuration
@EnableConfigurationProperties(ShardDataSourceProperties.class)
public class ShardDataSourceConfig {
@Autowired
private ShardDataSourceProperties shardDataSourceProperties;
private DruidDataSource parentDs() throws SQLException {
DruidDataSource ds = new DruidDataSource();
ds.setDriverClassName(shardDataSourceProperties.getDriverClassName());
ds.setUsername(shardDataSourceProperties.getUsername());
ds.setUrl(shardDataSourceProperties.getUrl());
ds.setPassword(shardDataSourceProperties.getPassword());
ds.setFilters(shardDataSourceProperties.getFilters());
ds.setMaxActive(shardDataSourceProperties.getMaxActive());
ds.setInitialSize(shardDataSourceProperties.getInitialSize());
ds.setMaxWait(shardDataSourceProperties.getMaxWait());
ds.setMinIdle(shardDataSourceProperties.getMinIdle());
ds.setTimeBetweenEvictionRunsMillis(shardDataSourceProperties.getTimeBetweenEvictionRunsMillis());
ds.setMinEvictableIdleTimeMillis(shardDataSourceProperties.getMinEvictableIdleTimeMillis());
ds.setValidationQuery(shardDataSourceProperties.getValidationQuery());
ds.setTestWhileIdle(shardDataSourceProperties.isTestWhileIdle());
ds.setTestOnBorrow(shardDataSourceProperties.isTestOnBorrow());
ds.setTestOnReturn(shardDataSourceProperties.isTestOnReturn());
ds.setPoolPreparedStatements(shardDataSourceProperties.isPoolPreparedStatements());
ds.setMaxPoolPreparedStatementPerConnectionSize(
shardDataSourceProperties.getMaxPoolPreparedStatementPerConnectionSize());
ds.setRemoveAbandoned(shardDataSourceProperties.isRemoveAbandoned());
ds.setRemoveAbandonedTimeout(shardDataSourceProperties.getRemoveAbandonedTimeout());
ds.setLogAbandoned(shardDataSourceProperties.isLogAbandoned());
ds.setConnectionInitSqls(shardDataSourceProperties.getConnectionInitSqls());
return ds;
}
private DataSource ds0() throws SQLException {
DruidDataSource ds = parentDs();
ds.setUsername(shardDataSourceProperties.getUsername0());
ds.setUrl(shardDataSourceProperties.getUrl0());
ds.setPassword(shardDataSourceProperties.getPassword0());
return ds;
}
private DataSource ds1() throws SQLException {
DruidDataSource ds = parentDs();
ds.setUsername(shardDataSourceProperties.getUsername1());
ds.setUrl(shardDataSourceProperties.getUrl1());
ds.setPassword(shardDataSourceProperties.getPassword1());
return ds;
}
private DataSourceRule dataSourceRule() throws SQLException {
Map<String, DataSource> dataSourceMap = new HashMap<>(2);
dataSourceMap.put("ds_0", ds0());
dataSourceMap.put("ds_1", ds1());
DataSourceRule dataSourceRule = new DataSourceRule(dataSourceMap);
return dataSourceRule;
}
//对order对策略
private TableRule orderTableRule() throws SQLException {
TableRule orderTableRule = TableRule.builder("t_order").actualTables(Arrays.asList("t_order_0", "t_order_1"))
.dataSourceRule(dataSourceRule()).build();
return orderTableRule;
}
//分库分表策略
private ShardingRule shardingRule() throws SQLException {
ShardingRule shardingRule = ShardingRule.builder().dataSourceRule(dataSourceRule())
.tableRules(Arrays.asList(orderTableRule(), orderItemTableRule()))
.databaseShardingStrategy(
new DatabaseShardingStrategy("user_id", new ModuloDatabaseShardingAlgorithm()))
.tableShardingStrategy(new TableShardingStrategy("order_id", new ModuloTableShardingAlgorithm()))
.build();
return shardingRule;
}
@Bean
public DataSource dataSource() throws SQLException {
return ShardingDataSourceFactory.createDataSource(shardingRule());
}
@Bean
public PlatformTransactionManager transactionManager() throws SQLException {
return new DataSourceTransactionManager(dataSource());
}
}
我们需要从controller调用接口进行对数据的增加和查询
下面所有的类都是用来模拟请求进行测试
@RestController
@RequestMapping("/order")
public class OrderController {
@Autowired
private OrderDao orderDao;
@RequestMapping(path = "/createOrder/{userId}/{orderId}", method = {RequestMethod.GET})
public String createOrder(@PathVariable("userId") Integer userId, @PathVariable("orderId") Integer orderId) {
Order order = new Order();
order.setOrderId(orderId);
order.setUserId(userId);
orderDao.createOrder(order);
return "success";
}
@RequestMapping(path = "/{userId}", method = {RequestMethod.GET})
public List<Order> getOrderListByUserId(@PathVariable("userId") Integer userId) {
return orderDao.getOrderListByUserId(userId);
}
}
---------------------------------------------------
public interface OrderDao {
List<Order> getOrderListByUserId(Integer userId);
void createOrder(Order order);
}
---------------------------------------------------
@Service
public class OrderDaoImpl implements OrderDao {
@Autowired
JdbcTemplate jdbcTemplate;
@Override
public List<Order> getOrderListByUserId(Integer userId) {
StringBuilder sqlBuilder = new StringBuilder();
sqlBuilder
.append("select order_id, user_id from t_order where user_id=? ");
return jdbcTemplate.query(sqlBuilder.toString(), new Object[]{userId},
new int[]{Types.INTEGER}, new BeanPropertyRowMapper<Order>(
Order.class));
}
@Override
public void createOrder(Order order) {
StringBuffer sb = new StringBuffer();
sb.append("insert into t_order(user_id, order_id)");
sb.append("values(");
sb.append(order.getUserId()).append(",");
sb.append(order.getOrderId());
sb.append(")");
jdbcTemplate.update(sb.toString());
}
}
---------------------------------------------------
public class Order implements Serializable {
private int userId;
private int orderId;
---------------------------------------------------
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
测试
启动项目，访问：http://localhost:8050/order/createOrder/1/1
更换参数多次访问，可以插入多条记录，观察你的数据库入库情况，已经按照我们制定的分库分表策略进行划分了。
需要注意的是
shareding是不支持jdbctemplate的批量修改操作的。
表名前不要加上库名，原生的情况加库名，不加库名其实是一样的，但使用shareding的表就会报错。
如果想进行只分表不分库的话
- 注释掉 ModuloDatabaseShardingAlgorithm 类
- 还有ShardDataSourceConfig.shardingRule() 中的分库策略那行代码
- 还有相关数据源配置改成 1 个
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