java - @Converter(autoApply = true) 不工作

Question

@Converter 即使添加了 autoApply = true 也不会应用。当 @Convert 添加到字段本身时有效。

这是Converter的代码

package com.example.hibernate.model;

@Converter(autoApply = true)
public class HeightConverter implements AttributeConverter<Height, Integer> {
    public Integer convertToDatabaseColumn(Height height) {//convert}
    public Height convertToEntityAttribute(Integer dbData) {//convert}
}

使用 Height 的类

package com.example.hibernate.model;

@Entity
@Table(name = "student")
public class Student implements Serializable {
    @Id
    @GeneratedValue(generator = "MY_S")
    private int id;

    // works if @Convert is applied
    // @Convert( converter = HeightConverter.class, disableConversion = false )

    @Column(name = "height_in_cm")
    private Height height;

    //getter setter

}

我正在使用 JPA 2.1(Hibernate 5.2.6.FINAL)

编辑:

persistence.xml

<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
             http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
             version="2.1">

    <persistence-unit name="persistence" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>

        <mapping-file>META-INF/orm.xml</mapping-file>
        <class>com.example.hibernate.model.Student</class>
        <exclude-unlisted-classes>false</exclude-unlisted-classes>

        <properties>
            <property name="packagesToScan" value="com.example.hibernate.model" />
            <property name="hibernate.archive.autodetection" value="class" />
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
            <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
            <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/test_db1?useSSL=false" />
            <property name="hibernate.connection.username" value="root" />
            <property name="hibernate.connection.password" value="password" />
            <property name="hibernate.show_sql" value="true"/>
            <property name="hibernate.format_sql" value="true"/>
            <property name="hibernate.flushMode" value="FLUSH_AUTO" />
            <property name="hibernate.hbm2ddl.auto" value="create-drop" />
        </properties>

    </persistence-unit>
</persistence>

Answer 1

您需要确保带@Converter 注解的类是扫描包的一部分。这为我们解决了问题。

 public LocalContainerEntityManagerFactoryBean entityManager(DataSource dataSource) {
    LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
    em.setPackagesToScan("your.converter.package","your.entities.package");
    ...

在我们的案例中，由于某些原因必须以编程方式进行 em 配置，但也可以通过其他方式实现。