java column: password (should be mapped with insert=“false“ update=“false“)

本文探讨了在定义数据库字段时出现的重复问题,特别是针对长度限定为255的密码字段进行了详细解析。该问题可能导致应用程序无法正常运行。
    @Column(length=255, name = "password") //密码
    private String password;

    @Column(length=255, name = "password")
    private String uid;

很有可能是你字段重复导致的这种错误

### 解决实体映射列重复问题 实体映射列重复(`reference_id`)通常是由于在实体类中重复定义了相同的列名,或者在 JPA 配置中出现了冲突。需要检查实体类的注解,确保每个列名只定义一次。 例如,以下是一个可能存在问题的实体类: ```java import javax.persistence.Entity; import javax.persistence.Column; import javax.persistence.Id; @Entity public class MyEntity { @Id private Long id; @Column(name = "reference_id") private String referenceId1; @Column(name = "reference_id") private String referenceId2; // 这里重复定义了 reference_id // Getters and setters } ``` 需要修改为: ```java import javax.persistence.Entity; import javax.persistence.Column; import javax.persistence.Id; @Entity public class MyEntity { @Id private Long id; @Column(name = "reference_id") private String referenceId; // Getters and setters } ``` ### 结合 JPA oneToOne 关联查询子表无实体配置的处理 由于子表没有实体配置,不能使用常规的 JPA `OneToOne` 注解关联。可以采用原生 SQL 查询、`@SqlResultSetMapping` 或 `Criteria API` 进行原生查询。 #### 原生 SQL 查询 ```java import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import java.util.List; import java.util.Map; public class CustomRepository { @PersistenceContext private EntityManager entityManager; public List<Map<String, Object>> performOneToOneQuery() { String sql = "SELECT main_table.id, main_table.name, sub_table.sub_column " + "FROM main_table " + "JOIN sub_table ON main_table.id = sub_table.main_table_id"; return entityManager.createNativeQuery(sql).getResultList(); } } ``` #### `@SqlResultSetMapping` ```java import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.SqlResultSetMapping; import javax.persistence.ConstructorResult; import javax.persistence.ColumnResult; import java.util.List; @Entity @SqlResultSetMapping( name = "MainSubMapping", classes = { @ConstructorResult( targetClass = MainSubDto.class, columns = { @ColumnResult(name = "id", type = Long.class), @ColumnResult(name = "name", type = String.class), @ColumnResult(name = "sub_column", type = String.class) } ) } ) class MainSubDto { private Long id; private String name; private String subColumn; public MainSubDto(Long id, String name, String subColumn) { this.id = id; this.name = name; this.subColumn = subColumn; } // Getters and setters } public class CustomRepository { @PersistenceContext private EntityManager entityManager; public List<MainSubDto> performOneToOneQueryWithMapping() { String sql = "SELECT main_table.id, main_table.name, sub_table.sub_column " + "FROM main_table " + "JOIN sub_table ON main_table.id = sub_table.main_table_id"; return entityManager.createNativeQuery(sql, "MainSubMapping").getResultList(); } } ``` #### `Criteria API` 进行原生查询 ```java import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import javax.persistence.criteria.CriteriaBuilder; import javax.persistence.criteria.CriteriaQuery; import javax.persistence.criteria.Root; import java.util.List; public class CustomRepository { @PersistenceContext private EntityManager entityManager; public List<Object[]> performOneToOneQueryWithCriteria() { CriteriaBuilder cb = entityManager.getCriteriaBuilder(); CriteriaQuery<Object[]> cq = cb.createQuery(Object[].class); Root<MainEntity> mainRoot = cq.from(MainEntity.class); cq.multiselect(mainRoot.get("id"), mainRoot.get("name")); // 这里可以添加连接条件 return entityManager.createQuery(cq).getResultList(); } } ``` ### 确保 Hibernate SessionFactory 正常构建 确保 Hibernate 的配置正确,`SessionFactory` 能够正常创建。可以参考以下配置: ```java import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.orm.hibernate5.LocalSessionFactoryBean; import javax.sql.DataSource; import java.util.Properties; @Configuration public class HibernateConfig { @Bean public LocalSessionFactoryBean sessionFactory(DataSource dataSource) { LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean(); sessionFactory.setDataSource(dataSource); sessionFactory.setPackagesToScan("com.example.entities"); Properties hibernateProperties = new Properties(); hibernateProperties.put("hibernate.dialect", "org.hibernate.dialect.MySQL8Dialect"); hibernateProperties.put("hibernate.show_sql", "true"); sessionFactory.setHibernateProperties(hibernateProperties); return sessionFactory; } } ```
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