springboot使用JPA集成sharding-jdbc进行分表

1. 本文目标

1.1 使用sharding-sphere提供的 sharding-jdbc-spring-boot-starter 分表组件去和JPA项目集成。

1.2 实现自己的分表算法(使用行表达式取模+自定义算法两种)。

1.3 分库本文不做研究，原理都一样。

2. 项目搭建

application.properties:

spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://139.199.171.136:3306/test?characterEncoding=utf8&useSSL=false
spring.datasource.username=root
spring.datasource.password=root

maven依赖：

    
        org.springframework.boot
        spring-boot-starter-parent
        2.0.4.RELEASE
         
    

    
        
            org.springframework.boot
            spring-boot-starter-web
        

        
            org.springframework.boot
            spring-boot-starter-data-jpa
        

        
            mysql
            mysql-connector-java
            5.1.47
        

        
            io.shardingsphere
            sharding-jdbc-spring-boot-starter
            3.0.0.M2
        

        
            com.alibaba
            druid
            1.1.9
        

        
            org.springframework.boot
            spring-boot-starter-test
        
    

然后我们先把基础的JPA调通

UserAuthEntity.java，这个类是用户认证表对应的实体类：

/**
 * 用户认证信息
 */
@Entity
@Table(name = "USER_AUTH",
        uniqueConstraints = {
                @UniqueConstraint(name = "USER_AUTH_PHONE",columnNames = {"PHONE"}),
                @UniqueConstraint(name = "USER_AUTH_EMAIL",columnNames = {"EMAIL"})
                }
        )
public class UserAuthEntity implements Serializable {

    private static final long serialVersionUID = -3050810548161476299L;

    @Id
    @Column(name = "USER_ID")
    private Integer userId;


    @Column(name = "PHONE",length = 16)
    private String phone;

    @Column(name = "EMAIL",length = 16)
    private String email;

    @Column(name = "LOCAL_PASSWORD",length = 32,nullable = false)
    private String localPassword;

    public Integer getUserId() {
        return userId;
    }

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

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getLocalPassword() {
        return localPassword;
    }

    public void setLocalPassword(String localPassword) {
        this.localPassword = localPassword;
    }
}

对应的DAO:

@Repository
public interface UserAuthDao extends JpaRepository {

    public List findByUserIdBetween(int start, int end);
}

MyFriendEntity.java，我的好友 表 对应的实体类

@Entity
@Table(name = "MY_FRIEND")
public class MyFriendEntity implements Serializable {

    private static final long serialVersionUID = -952799334936333550L;

    @EmbeddedId
    private MyFriendEntityId myFriendId;

    @Column(name = "REMARK",length = 16)
    private String remark;

    @Column(name = "ADD_DATE",nullable = false,columnDefinition = " datetime default now() ")
    private LocalDateTime addDate;

    public MyFriendEntityId getMyFriendId() {
        return myFriendId;
    }

    public void setMyFriendId(MyFriendEntityId myFriendId) {
        this.myFriendId = myFriendId;
    }

    public String getRemark() {
        return remark;
    }

    public void setRemark(String remark) {
        this.remark = remark;
    }

    public LocalDateTime getAddDate() {
        return addDate;
    }

    public void setAddDate(LocalDateTime addDate) {
        this.addDate = addDate;
    }

}

MyFriendEntityId.java：

对应的DAO：

@Repository
public interface MyFriendDao extends JpaRepository {


}

单元测试：

@RunWith(SpringRunner.class)
@SpringBootTest
public class TestShardingSphere {

    @Autowired
    MyFriendDao myFriendDao;

    @Autowired
    UserAuthDao userAuthDao;

    @Test
    public void testInsert(){
        MyFriendEntity friendEntity = new MyFriendEntity();
        friendEntity.setMyFriendId(new MyFriendEntityId(3,"5"));
        friendEntity.setAddDate(LocalDateTime.now());
        myFriendDao.save(friendEntity);

        friendEntity.setMyFriendId(new MyFriendEntityId(5,"5"));
        friendEntity.setAddDate(LocalDateTime.now());
        myFriendDao.save(friendEntity);

        friendEntity.setMyFriendId(new MyFriendEntityId(6,"5"));
        friendEntity.setAddDate(LocalDateTime.now());
        myFriendDao.save(friendEntity);

        UserAuthEntity user = new UserAuthEntity();
        user.setUserId(2);
        user.setLocalPassword("123");
        userAuthDao.save(user);
    }

}

数据正常插入...

然后我们对MY_FRIEND进行分表，对USER_ID取模10，将一个表分为MY_FRIEND_0、MY_FRIEND_1....MY_FRIEND_9一共10个表，注意，我们需手动创建这10个表，否则会报table not exists。

参照官方文档的配置使用行表达式进行分表，调整application.properties为如下：

spring.jpa.hibernate.ddl-auto=none
spring.jpa.show-sql=true
spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect

sharding.jdbc.datasource.names=test
sharding.jdbc.datasource.test.type=com.alibaba.druid.pool.DruidDataSource
sharding.jdbc.datasource.test.driver-class-name=com.mysql.jdbc.Driver
sharding.jdbc.datasource.test.url=jdbc:mysql://192.168.1.113/test?characterEncoding=utf8&useSSL=false/oochart?characterEncoding=utf8&useSSL=false
sharding.jdbc.datasource.oochart.username=root
sharding.jdbc.datasource.oochart.password=root

#所有数据节点
sharding.jdbc.config.sharding.tables.MY_FRIEND.actual-data-nodes=test.MY_FRIEND_$->{0..9}
#根据这个列分表
sharding.jdbc.config.sharding.tables.MY_FRIEND.table-strategy.inline.sharding-column=USER_ID
#分表规则为:对USER_ID取模
sharding.jdbc.config.sharding.tables.MY_FRIEND.table-strategy.inline.algorithm-expression=test.MY_FRIEND_$->{USER_ID % 10}

再次运行单元测试的testInsert()方法，可以看到数据分别插入到了3个不同后缀的MY_FRIEND_X表中。

增加单元测试方法:

    @Test
    public void testQuery(){
        Optional byId = myFriendDao.findById(new MyFriendEntityId(6, "5"));
        byId.ifPresent(one -> System.out.println(one.getMyFriendId().getFriendId()));

        List all = myFriendDao.findAll();
        System.out.println(all);
    }

运行查看结果，数据可以全部取到。

以上是通过行表达式进行取模的简单分片，下面将实现我们自定义的分片算法。

查看官方的文档，我们需要通过这个类来配置我们的分片算法：

修改application.properties如下：

spring.jpa.hibernate.ddl-auto=none
spring.jpa.show-sql=true
spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect

sharding.jdbc.datasource.names=test
sharding.jdbc.datasource.test.type=com.alibaba.druid.pool.DruidDataSource
sharding.jdbc.datasource.test.driver-class-name=com.mysql.jdbc.Driver
sharding.jdbc.datasource.test.url=jdbc:mysql://192.168.1.113/test?characterEncoding=utf8&useSSL=false/oochart?characterEncoding=utf8&useSSL=false
sharding.jdbc.datasource.oochart.username=root
sharding.jdbc.datasource.oochart.password=root

#所有数据节点
sharding.jdbc.config.sharding.tables.MY_FRIEND.actual-data-nodes=test.MY_FRIEND_$->{0..9}
#根据这个列分表
sharding.jdbc.config.sharding.tables.MY_FRIEND.table-strategy.inline.sharding-column=USER_ID
#分表规则为:对USER_ID取模
sharding.jdbc.config.sharding.tables.MY_FRIEND.table-strategy.inline.algorithm-expression=test.MY_FRIEND_$->{USER_ID % 10}

#分片列
sharding.jdbc.config.sharding.default-table-strategy.standard.sharding-column=USER_ID
#精确分片算法，用于=和IN,实现类
sharding.jdbc.config.sharding.default-table-strategy.standard.precise-algorithm-class-name=com.solider76.oo.service.chat.config.MyShardingConfig
#范围分片算法，用于BETWEEN,实现类
sharding.jdbc.config.sharding.default-table-strategy.standard.range-algorithm-class-name=com.solider76.oo.service.chat.config.MyShardingConfig

分片算法实现类：

public class MyShardingConfig implements PreciseShardingAlgorithm, RangeShardingAlgorithm {

    /**
     * 精确分片算法
     * 将user_id的值和5比较，如果小于等于5，数据对应的表为：USER_AUTH_1
     * 将user_id的值和5比较，如果大于5，数据对应的表为：USER_AUTH_2
     * @param availableTargetNames
     * @param shardingValue
     * @return
     */
    @Override
    public String doSharding(Collection availableTargetNames, PreciseShardingValue shardingValue) {
        if(availableTargetNames.contains("user_auth")){
            if(shardingValue.getColumnName().equalsIgnoreCase("USER_ID")){
                Comparable value = shardingValue.getValue();
                int i = value.compareTo(5);
                int suffix = -1;
                if(i<=0){
                    suffix = 1;
                }else{
                    suffix = 2;
                }
                String s = ("user_auth_" + suffix).toUpperCase();
                return s;
            }
        }
        return null;
    }

    /**
     * lower 为 between and 中的较小值
     * upper 为 between and 中的较大值
     * 如果lower小于等于5，tables集合中就要加入USER_AUTH_1表
     * 如果lower大于5，tables集合中就要加入USER_AUTH_2表
     * @param availableTargetNames
     * @param shardingValue
     * @return
     */
    @Override
    public Collection doSharding(Collection availableTargetNames, RangeShardingValue shardingValue) {

        Collection tables = new HashSet<>();
        if(availableTargetNames.contains("user_auth")){
            if(shardingValue.getColumnName().equalsIgnoreCase("USER_ID")){
                Comparable lower = shardingValue.getValueRange().lowerEndpoint();
                Comparable upper = shardingValue.getValueRange().upperEndpoint();

                int lowerResult = lower.compareTo(5);
                int upperResult = upper.compareTo(5);

                if(lowerResult<=0){
                    tables.add("user_auth_1".toUpperCase());
                    if(upperResult>0){
                        tables.add("user_auth_2".toUpperCase());
                    }
                }else{
                    tables.add("user_auth_2".toUpperCase());
                }
            }
        }
        return tables;
    }
}

为了方便展示，这里的代码写的较为粗略，实际的算法在这里实现，我这里只是简单的将USER_ID和5比较然后根据结果取不同的表。同样的，这里也需要先创建表USER_AUTH_1、USER_AUTH_2。

新增test方法：

    @Test
    public void testCustomerConfigInsert(){
        UserAuthEntity user = new UserAuthEntity();
        user.setUserId(2);
        user.setLocalPassword("123");
        userAuthDao.save(user);

        user.setUserId(8);
        user.setLocalPassword("123");
        userAuthDao.save(user);

        user.setUserId(11);
        user.setLocalPassword("123");
        userAuthDao.save(user);

        user.setUserId(3);
        user.setLocalPassword("123");
        userAuthDao.save(user);
    }

    @Test
    public void testCustomerConfigQuery(){
        Optional byId = userAuthDao.findById(2);
        System.out.println(byId.isPresent());
    }

    @Test
    public void testBetween(){
        List byUserIdBetween = userAuthDao.findByUserIdBetween(8, 11);
        for(UserAuthEntity user : byUserIdBetween){
            System.out.println("id:"+user.getUserId());
        }
    }

正常输出结果。。。

3. 其他说明

1. 这里只是简单的进行了分表，功能只是sharding-sphere的冰山一角。

2. 项目中MySql版本为5.X，已知如果使用MySql8.0.12启动会报语法错误，已查明是8.0.12的mysql驱动bug，oracle官网已经记载了此bug，8.0.12之后应该会修复：

Caused by: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'ORDER BY TABLE_TYPE, TABLE_SCHEMA, TABLE_NAME' at line 1
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120) ~[mysql-connector-java-8.0.12.jar:8.0.12]
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.12.jar:8.0.12]
	at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) ~[mysql-connector-java-8.0.12.jar:8.0.12]
	at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:975) ~[mysql-connector-java-8.0.12.jar:8.0.12]
	at com.mysql.cj.jdbc.ClientPreparedStatement.executeQuery(ClientPreparedStatement.java:1025) ~[mysql-connector-java-8.0.12.jar:8.0.12]
	at com.mysql.cj.jdbc.DatabaseMetaDataUsingInfoSchema.executeMetadataQuery(DatabaseMetaDataUsingInfoSchema.java:70) ~[mysql-connector-java-8.0.12.jar:8.0.12]
	at com.mysql.cj.jdbc.DatabaseMetaDataUsingInfoSchema.getTables(DatabaseMetaDataUsingInfoSchema.java:843) ~[mysql-connector-java-8.0.12.jar:8.0.12]
	at io.shardingsphere.core.metadata.table.executor.TableMetaDataInitializer.getAllTableNames(TableMetaDataInitializer.java:90) ~[sharding-core-3.0.0.M2.jar:na]
	at io.shardingsphere.core.metadata.table.executor.TableMetaDataInitializer.loadDefaultTables(TableMetaDataInitializer.java:80) ~[sharding-core-3.0.0.M2.jar:na]
	at io.shardingsphere.core.metadata.table.executor.TableMetaDataInitializer.load(TableMetaDataInitializer.java:61) ~[sharding-core-3.0.0.M2.jar:na]
	... 55 common frames omitted