hibernate - 调用deleteallby方法时如何修复 'no entitymanager with actual transaction'？

Question

我正在构建一个 Spring Boot 后端，并想要创建一个休息端点，该端点会按供应商 ID 删除所有项目。当我调用其余端点时，我收到“没有可用的实际事务的实体管理器”异常。

如何修复此错误？

我尝试了@Transactional注释，但错误仍然发生

型号:

public class Item {

    public Item() {}

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "ItemId")
    private int id;
    public int getId() {
        return this.id;
    }
    public void setId(int Id) {
        this.id = Id;
    }

    @Column(name = "Suppid")
    private int suppid;
    public int getSuppid() {
        return this.suppid;
    }
    public void setSuppid(int Suppid) {
        this.suppid = Suppid;
    }  
}

存储库:

public interface ItemRepository extends CrudRepository<Item, Integer> {
    @Transactional
    public void deleteAllBySuppid(int suppid);
}

Controller :

public void deleteSupplier(@RequestParam(name = "suppid") int suppid) {

    itemrepo.deleteAllBySuppid(suppid);
    supprepo.delete(supprepo.findByid(suppid));
}

pom.xml

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

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

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

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>

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

    <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.0</version>
    </dependency>

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>5.4.0.Final</version>
    </dependency>
</dependencies>

我希望该项目被删除，但它抛出:

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.InvalidDataAccessApiUsageException: No EntityManager with actual transaction available for current thread - cannot reliably process 'remove' call; nested exception is javax.persistence.TransactionRequiredException: No EntityManager with actual transaction available for current thread - cannot reliably process 'remove' call] with root cause

Answer 1

解释为什么需要@Transactional:

当您查看 CrudMethodMetadataPostProcessor.postProcess 方法时，implementations 集中包含的所有方法都会通过 TransactionSynchronizationManager 进行调用。 Custum Functions需要手动添加Transactions。