jpa mongodb分表代码

下面是使用JPA和MongoDB进行分表的代码示例：

1. 实体类定义

import org.springframework.data.mongodb.core.mapping.Document;
import xyz.chitgupta.demo.mongodb.shard.annotation.ShardingKey;

@Document(collection = "user")
public class User {
    @ShardingKey
    private String id;
    private String name;
    private int age;
    // ... 其他属性和方法
}

2. Repository 定义

import org.springframework.data.mongodb.repository.MongoRepository;

public interface UserRepository extends MongoRepository<User, String> {
    // ... 其他自定义方法
}

3. 分片配置

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.MongoClientFactoryBean;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.mapping.event.ValidatingMongoEventListener;
import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;

@Configuration
public class ShardingConfig {
    @Bean
    public MongoClientFactoryBean mongo() {
        MongoClientFactoryBean mongo = new MongoClientFactoryBean();
        mongo.setHost("localhost");
        mongo.setPort(27017);
        return mongo;
    }

    @Bean
    public MongoTemplate mongoTemplate() throws Exception {
        MongoTemplate template = new MongoTemplate(mongo().getObject(), "database_name");
        return template;
    }

    @Bean
    public LocalValidatorFactoryBean validator() {
        return new LocalValidatorFactoryBean();
    }

    @Bean
    public ValidatingMongoEventListener validatingMongoEventListener() {
        return new ValidatingMongoEventListener(validator());
    }
}

4. 分片实现

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.query.Query;
import org.springframework.stereotype.Service;
import xyz.chitgupta.demo.mongodb.shard.annotation.ShardingCollection;

@Service
@ShardingCollection(collectionName = "user_{%02d}")
public class UserServiceImpl implements UserService {
    @Autowired
    private MongoTemplate mongoTemplate;

    @Autowired
    private UserRepository userRepository;

    @Override
    public User save(User user) {
        return userRepository.save(user);
    }

    @Override
    public User findById(String id) {
        Query query = new Query();
        query.addCriteria(Criteria.where("id").is(id));
        return mongoTemplate.findOne(query, User.class);
    }

    // ... 其他方法
}

需要注意的是，在`@ShardingCollection`注解中，可以使用`{%d}`、`{%02d}`等格式化字符串来指定集合名称的模板。例如，`@ShardingCollection(collectionName = "user_{%02d}")`表示将数据分片存储在名为`user_01`、`user_02`等的集合中。在上面的示例中，我们使用了`user_{%02d}`模板来实现分片。