如何自定义 JPA 的数据库命名策略

@Data
@Entity
public class Teacher {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @Column(name = "Name")
    private String name;

}

@Data
@Entity
@Table(name = "teacher_class")
public class TeacherClass {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    private Integer teacherId;

    @Column(name = "ClassName")
    private String className;

}

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false
  jpa:
    database-platform: org.hibernate.dialect.MySQL5InnoDBDialect
    show-sql: true
    hibernate:
      ddl-auto: create
      naming:
         # 1. 表名及字段全小写下划线分隔命名策略(默认)
         physical-strategy: org.springframework.boot.orm.jpa.hibernate.SpringPhysicalNamingStrategy

Hibernate: create table teacher (id integer not null auto_increment, name varchar(255), primary key (id)) engine=InnoDB
Hibernate: create table teacher_class (id integer not null auto_increment, class_name varchar(255), teacher_id integer, primary key (id)) engine=InnoDB

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false
  jpa:
    database-platform: org.hibernate.dialect.MySQL5InnoDBDialect
    show-sql: true
    hibernate:
      ddl-auto: create
      naming:
         # 2. 物理命名策略，未定义 @Table 和 @Column 将以实体名和属性名作为表名及字段名
         physical-strategy: org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl

Hibernate: create table Teacher (id integer not null auto_increment, Name varchar(255), primary key (id)) engine=InnoDB
Hibernate: create table teacher_class (id integer not null auto_increment, ClassName varchar(255), teacherId integer, primary key (id)) engine=InnoDB

public class CustomNamingStrategyConfig extends SpringPhysicalNamingStrategy {

    /**
     * 配置映射的数据表名
     *
     * @param name
     * @param jdbcEnvironment
     * @return
     */
    @Override
    public Identifier toPhysicalTableName(Identifier name, JdbcEnvironment jdbcEnvironment) {
        if (name == null) {
            return null;
        }
        // 实体名 or 自定义的@Tabel name属性值
        String text = name.getText();

        // 首字母大写(类名)，实体未定义@Table, 为表名加上tb_前缀
        if (Character.isUpperCase(text.charAt(0))) {
            final String tb = "tb_";
            if (!text.contains(tb)) {
                text = "tb" + text;
            }

            StringBuilder builder = new StringBuilder(text.replace('.', '_'));
            for (int i = 1, maxLength = builder.length() - 1; i < maxLength; i++) {
                if (this.isUnderscoreRequired(builder.charAt(i - 1), builder.charAt(i), builder.charAt(i + 1))) {
                    builder.insert(i++, '_');
                }
            }
            return super.getIdentifier(builder.toString(), name.isQuoted(), jdbcEnvironment);
        } else {
            // 实体定义了@Table(name="xxx")，以name属性值为表名
            return super.getIdentifier(text, name.isQuoted(), jdbcEnvironment);
        }
    }

    /**
     * 判断是否前一个字符为小写字母，当前字符为大写字母，下一个字符为小写字母
     *
     * @param before
     * @param current
     * @param after
     * @return
     */
    private boolean isUnderscoreRequired(char before, char current, char after) {
        return Character.isLowerCase(before) && Character.isUpperCase(current) && Character.isLowerCase(after);
    }

    /**
     * 配置映射的字段名
     *
     * @param name
     * @param jdbcEnvironment
     * @return
     */
    @Override
    public Identifier toPhysicalColumnName(Identifier name, JdbcEnvironment jdbcEnvironment) {
        // 实体的属性名 or 自定义的@Column name属性值
        String text = name.getText();

        if (Character.isUpperCase(text.charAt(0))) {
            // 大写字母下划线分隔命名策略，有在实体字段上自定义@Column(name="Xx_Xxx")
            return new Identifier(text, name.isQuoted());
        } else {
            // 常见的小写驼峰式命名策略
            return super.toPhysicalColumnName(name, jdbcEnvironment);
        }
    }

}

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false
  jpa:
    database-platform: org.hibernate.dialect.MySQL5InnoDBDialect
    show-sql: true
    hibernate:
      ddl-auto: create
      naming:
        # 3. 自定义的命名策略
        physical-strategy: cn.mariojd.jpa.naming.config.CustomNamingStrategyConfig

Hibernate: create table tb_teacher (id integer not null auto_increment, Name varchar(255), primary key (id)) engine=InnoDB
Hibernate: create table teacher_class (id integer not null auto_increment, ClassName varchar(255), teacher_id integer, primary key (id)) engine=InnoDB