使用 SpringPhysicalNamingStrategy 启动多个数据源

问题描述

需要配置多个数据源的 Spring 启动应用程序。 多数据源配置使用单独的 id_token、datasource 和 entityManager。

此外，休眠命名配置正在使用具有以下配置的单个数据源。 transactionManager

以上配置可以通过JPA属性提供给entityManager。但无法在 SpringPhysicalNamingStrategy 中添加动态表名（来自 application.properties）。

解决方法

我创建了自定义物理命名策略。它可以使用环境变量更改名称。此外，它也可以更改列名。名称标识符将由数据库目录名称决定。您可以使用 jdbcEnvironment 更改选择标准。如果您输入任何标准选项，则文本将是属性值。

应用属性

spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=password
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect

spring.jpa.show-sql=true

spring.jpa.hibernate.naming.physical-strategy=com.example.demo.DynamicPhysicalNamingStrategy

# dynamic
user.table.name=TESTDB:TestUser,TESTDB2:TestUser2
user.column.name=username

用户实体

@Table(name = "${user.table.name}")
@Entity
@Data
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;

    @Column(name = "${user.column.name}")
    private String name;

    private String email;
}

动态物理命名策略

package com.example.demo;

import org.hibernate.boot.model.naming.Identifier;
import org.hibernate.boot.model.naming.PhysicalNamingStrategy;
import org.hibernate.engine.jdbc.env.spi.JdbcEnvironment;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Component;
import org.springframework.util.Assert;

import java.util.Locale;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * It is copied from {@link org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl}
 */
@Component
public class DynamicPhysicalNamingStrategy implements PhysicalNamingStrategy,ApplicationContextAware {
    private final Pattern VALUE_PATTERN = Pattern.compile("^\\$\\{([\\w.]+)}$");
    private Environment environment;

    @Override
    public Identifier toPhysicalCatalogName(Identifier name,JdbcEnvironment jdbcEnvironment) {
        return apply(name,jdbcEnvironment);
    }

    @Override
    public Identifier toPhysicalSchemaName(Identifier name,jdbcEnvironment);
    }

    @Override
    public Identifier toPhysicalTableName(Identifier name,jdbcEnvironment);
    }

    @Override
    public Identifier toPhysicalSequenceName(Identifier name,jdbcEnvironment);
    }

    @Override
    public Identifier toPhysicalColumnName(Identifier name,jdbcEnvironment);
    }

    private Identifier apply(Identifier name,JdbcEnvironment jdbcEnvironment) {
        if (name == null) {
            return null;
        }

        // Custom Implementation Start
        String text = name.getText();
        Matcher matcher = VALUE_PATTERN.matcher(text);
        if (matcher.matches()) {
            String propertyKey = matcher.group(1);
            text = environment.getProperty(propertyKey);
            Assert.notNull(text,"Property is not found '" + propertyKey + "'");

            // extract catalog selection part
            // Example:
            // Current Catalog: TESTDB
            // Property: TESTDB:TestUser,TESTDB2:TestUser
            // Text will be TestUser
            Pattern catalogPattern = Pattern.compile(jdbcEnvironment.getCurrentCatalog().getText() + ":([^,]+)");
            Matcher catalogMatcher = catalogPattern.matcher(text);
            if (catalogMatcher.find()) {
                text = catalogMatcher.group(1);
            }

            // Caution: You can remove below return function,if so text will be transformed with spring advice
            return getIdentifier(text,name.isQuoted(),jdbcEnvironment);
        }
        // Custom Implementation End


        StringBuilder builder = new StringBuilder(text.replace('.','_'));
        for (int i = 1; i < builder.length() - 1; i++) {
            if (isUnderscoreRequired(builder.charAt(i - 1),builder.charAt(i),builder.charAt(i + 1))) {
                builder.insert(i++,'_');
            }
        }
        return getIdentifier(builder.toString(),jdbcEnvironment);
    }

    /**
     * Get an identifier for the specified details. By default this method will return an
     * identifier with the name adapted based on the result of
     * {@link #isCaseInsensitive(JdbcEnvironment)}
     *
     * @param name            the name of the identifier
     * @param quoted          if the identifier is quoted
     * @param jdbcEnvironment the JDBC environment
     * @return an identifier instance
     */
    protected Identifier getIdentifier(String name,boolean quoted,JdbcEnvironment jdbcEnvironment) {
        if (isCaseInsensitive(jdbcEnvironment)) {
            name = name.toLowerCase(Locale.ROOT);
        }
        return new Identifier(name,quoted);
    }

    /**
     * Specify whether the database is case sensitive.
     *
     * @param jdbcEnvironment the JDBC environment which can be used to determine case
     * @return true if the database is case insensitive sensitivity
     */
    protected boolean isCaseInsensitive(JdbcEnvironment jdbcEnvironment) {
        return true;
    }

    private boolean isUnderscoreRequired(char before,char current,char after) {
        return Character.isLowerCase(before) && Character.isUpperCase(current) && Character.isLowerCase(after);
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        environment = applicationContext.getBean(Environment.class);
    }
}

测试

package com.example.demo;

import com.example.demo.entity.User;
import com.example.demo.repository.UserRepository;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
class DemoApplicationTests {
    @Autowired
    private UserRepository userRepository;

    @Test
    void contextLoads() {
        User user = new User();
        user.setName("test");
        user.setEmail("[email protected]");
        userRepository.save(user);

        userRepository.findAll();
    }

}

Hibernate: call next value for hibernate_sequence
Hibernate: insert into testuser (email,username,id) values (?,?,?)
Hibernate: select user0_.id as id1_0_,user0_.email as email2_0_,user0_.username as username3_0_ from testuser user0_