Java 如何在没有Spring引导的情况下使用JPA存储库

我有一个现有的Spring4项目（mvc、jdbc等），我试图将其移植到SpringBoot，但我做不到。（很多麻烦，没人能解释我是怎么做到的）。但现在我只想在现有项目中使用SpringDataJPA。 这是pom的一个主要依赖项：

<properties>
        <jetty.version>9.3.5.v20151012</jetty.version>
        <spring.version>4.3.12.RELEASE</spring.version>
        <spring.boot.version>1.5.8.RELEASE</spring.boot.version>
        <spring.security.version>4.2.3.RELEASE</spring.security.version>
        <quartz.version>2.2.1</quartz.version>
        <slf4j.version>1.7.5</slf4j.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <hibernate-version>5.3.3.Final</hibernate-version>
    </properties>

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web-services</artifactId>
            <version>${spring.boot.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-validation</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.jboss.logging</groupId>
                    <artifactId>jboss-logging</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>com.fasterxml.jackson.core</groupId>
                    <artifactId>jackson-core</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>com.fasterxml.jackson.core</groupId>
                    <artifactId>jackson-databind</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>com.fasterxml.jackson.core</groupId>
                    <artifactId>jackson-annotations</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.hibernate</groupId>
                    <artifactId>hibernate-validator</artifactId>
                </exclusion>

            </exclusions>
        </dependency>
    <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.4</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>2.0.5.RELEASE</version>
        </dependency>
<dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>${hibernate-version}</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>${hibernate-version}</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate.javax.persistence</groupId>
            <artifactId>hibernate-jpa-2.0-api</artifactId>
            <version>1.0.1.Final</version>
        </dependency>

<dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-config</artifactId>
            <version>4.2.1.RELEASE</version>
        </dependency>

用于测试的Derby数据库。但主要的数据库类型是带有HikariCP的PostgreSQL。我已经在项目中添加了HQL支持，它工作正常。但是当我尝试添加JAP存储库支持时，我遇到了很多问题。我有一个实体：

@Entity
@Table(name = "users", schema = "public", catalog = "test")
public class Users {
    private int id;
    private String username;
    private String password;
    private String email;

    @Id
    @Column(name = "id", nullable = false)
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    @Basic
    @Column(name = "username", nullable = false, length = 64)
    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    @Basic
    @Column(name = "password", nullable = false, length = 64)
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Basic
    @Column(name = "email", nullable = false, length = 128)
    public String getEmail() {
        return email;
    }

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

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Users that = (Users) o;
        return id == that.id &&
                Objects.equals(username, that.username) &&
                Objects.equals(password, that.password) &&
                Objects.equals(email, that.email);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id, username, password, email);
    }
}

和存储库：

@Repository
public interface UsersRepository extends CrudRepository<Users, Long> {

    @Query("select b from Users b where b.username = :username")
    Users findByName(@Param("username") String username);
}

仅此而已。 我不使用Spring Boot（如上所述）并在应用程序出现错误时启动：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in ru.testproject.config.DBConfig: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean]: Factory method 'entityManagerFactory' threw exception; nested exception is java.lang.NoSuchFieldError: parallelCapableClassLoaderAvailable
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:587)

如果我对@EnableJpaRepositories注释进行注释，则会出现以下错误：

Unsatisfied dependency expressed through field 'userServiceImpl'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userServiceImpl': Unsatisfied dependency expressed through field 'usersRepository'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'ru.testproject.db.hibernate.repository.UsersRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

在第二个场景中，存储库是空的，当然-JPA repo被禁用。。

---

求求你，救命！我做错了什么？我怎样才能让它起作用？我无法用谷歌和互联网解决我的问题。可能是因为我不明白根本问题是什么。

似乎您没有在组件扫描中添加测试包ru.testproject.db.hibernate.repository。

请向所有人求助！ 我已通过以下更改解决了我的问题： 1） 首先-我已经用更新的版本更新了spring上下文依赖关系：

<dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>5.0.4.RELEASE</version>
    </dependency>

注释。以前的变化对任何积极的变化都没有影响。1）导致entityManagerFactory错误，我可以用以下方法解决：

3） 使用为entityManagerFactory设置PackageToScan

entityManagerFactoryBean.setPackagesToScan("ru.testproject.hibernate.entity");

具有实体的路径（在这种情况下为用户）

仅此而已。现在存储库工作得很好。谢谢大家

---

ps：可能是，现在我可以从spring boot开始）

在该线程中，最后一条评论描述了EntityManagerFactory的相同问题。阅读手册并查看示例我已经检查了许多示例，下面的手册描述了spring boot配置。这并不是我想要的。你能试着将@EnableJpaRepositories（“ru.testproject.*）替换为@EnableJpaRepositories（“ru.testproject.db.hibernate.repository”）@ComponentScan（“ok.testproject.hibernate.repository”），但它不起作用，但显示“ru.testproject.db.hibernate.repository”包时出错。你能确认你使用了正确的软件包名称吗？是的，我刚刚重命名了软件包。但您是对的：一些问题是由错误的组件路径引起的

Unsatisfied dependency expressed through field 'userServiceImpl'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userServiceImpl': Unsatisfied dependency expressed through field 'usersRepository'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'ru.testproject.db.hibernate.repository.UsersRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

<dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>5.0.4.RELEASE</version>
    </dependency>

@EnableJpaRepositories(basePackages = {
        "ru.testproject.hibernate"
})
@PropertySource("classpath:testproject.properties")
@ComponentScan("ru.testproject.hibernate")

entityManagerFactoryBean.setPackagesToScan("ru.testproject.hibernate.entity");