我在尝试将Flyway集成进来进行数据库迁移，但现在卡在一个错误上。我大致认为错误信息是：架构验证失败：缺少表 [products]。我在resources/db下有两个SQL文件。起初我把它放在resources/db/migrations里，但在IDE中显示的路径是db.migrations，于是想到把它移动到db/。路径已在application.properties中更新。仍然不清楚该如何修复。我尝试了chatgpt/gemini提到的几种方法，但都没有成功。

V1__create_users_table.sql

CREATE TABLE users (
    id BIGINT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(20) NOT NULL,
    email VARCHAR(255) NOT NULL UNIQUE
);

V2__create_products_table.sql

CREATE TABLE products (
    id BIGINT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    price DOUBLE NOT NULL,
    user_id BIGINT NOT NULL,
    CONSTRAINT fk_products_user
        FOREIGN KEY (user_id)
        REFERENCES users(id)
        ON DELETE CASCADE
);

application.properties

spring.application.name=demo
# The location of your database (change 'my_db' to your actual database name)
spring.datasource.url=jdbc:mysql://localhost:3306/my_db

# Your MySQL credentials
spring.datasource.username=root
spring.datasource.password=****

# The Driver class (Spring usually finds this, but being explicit helps)
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

# Hibernate should only validate (NOT create)
spring.jpa.hibernate.ddl-auto=validate

# Optional but recommended
spring.jpa.show-sql=true

# Flyway
spring.flyway.enabled=true
spring.flyway.locations=classpath:db
#spring.flyway.baseline-on-migrate=true

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-parent</artifactId>
       <version>4.0.5</version>
       <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name/>
    <description/>
    <url/>
    <licenses>
       <license/>
    </licenses>
    <developers>
       <developer/>
    </developers>
    <scm>
       <connection/>
       <developerConnection/>
       <tag/>
       <url/>
    </scm>
    <properties>
       <java.version>26</java.version>
    </properties>
    <dependencies>
       <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-webmvc</artifactId>
       </dependency>

       <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-webmvc-test</artifactId>
          <scope>test</scope>
       </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
        </dependency>

        <dependency>
            <groupId>org.flywaydb</groupId>
            <artifactId>flyway-core</artifactId>
            <scope>compile</scope>
        </dependency>

        <dependency>
            <groupId>org.flywaydb</groupId>
            <artifactId>flyway-mysql</artifactId>
            <scope>compile</scope>
        </dependency>
    </dependencies>

    <build>
       <plugins>
          <plugin>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-maven-plugin</artifactId>
          </plugin>
       </plugins>
    </build>

</project>

User entity

package com.example.demo.user;

import com.example.demo.products.Product;
import com.fasterxml.jackson.annotation.JsonManagedReference;
import jakarta.persistence.*;
import jakarta.validation.constraints.*;

import java.util.ArrayList;
import java.util.List;

@Entity
@Table(name = "users")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false)
    @NotBlank(message = "Name is required")
    @Size(min = 3, max = 20, message = "Name must be between 3 and 20 characters")
    private String name;

    @Column(unique = true, nullable = false)
    private String email;

    @OneToMany(mappedBy = "user", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JsonManagedReference
    private List<Product> products = new ArrayList<>();

    public User() {} // Required by JPA
    public User(String name, String email, List<Product> products) {
        this.name = name;
        this.email = email;
    }

    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public String getEmail() { return email; }
    public void setEmail(String email) { this.email = email; }

    public void setProducts(List<Product> products) {
        this.products = products;
        if (products != null) {
            // Link the parent (this User) to every child (Product)
            for (Product p : products) {
                p.setUser(this);
            }
        }
    }

    public List<Product> getProducts() {
        return this.products;
    }
}

Product entity

package com.example.demo.products;

import com.example.demo.user.User;
import com.fasterxml.jackson.annotation.JsonBackReference;
import jakarta.persistence.*;

@Entity
@Table(name = "products")
public class Product {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    Long id;

    @Column(nullable = false)
    private String name;

    @Column(nullable = false)
    private double price;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "user_id", nullable = false)
    @JsonBackReference
    private User user;

    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public double getPrice() { return price; }
    public void setPrice(double price) { this.price = price; }

    public void setUser(User user) {
        this.user = user;
    }
}

解决方案

在Spring Boot 4.x中，你需要使用Flyway Starter，相比手动添加依赖要简单得多

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-flyway</artifactId>
</dependency>