Java 如何使用OneToMany?
我想链接2个实体:Java 如何使用OneToMany?,java,spring,hibernate,Java,Spring,Hibernate,我想链接2个实体: @Entity @Table(name = "company") public class Company { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Integer id; @Column(nullable = false, name = "company_name") private String companyName; @OneToMany(mappedBy = "company",
@Entity
@Table(name = "company")
public class Company {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
@Column(nullable = false, name = "company_name")
private String companyName;
@OneToMany(mappedBy = "company", cascade = CascadeType.ALL)
private List<Department> departments;
public Company(){
departments = new ArrayList<Department>();
}
// setters and getters
}
DAO类:
@Service
public class CompanyDAOImpl implements CompanyDAO {
@Autowired
private SessionFactory sessionFactory;
@Override
public void createCompany(Company company) {
sessionFactory.getCurrentSession().save(company);
}
}
服务级别:
@Service
public class CompanyServiceImpl implements CompanyService {
@Autowired
private CompanyDAO companyDAO;
@Override
@Transactional
public List readCompany() {
return companyDAO.readCompany();
}
@Override
@Transactional
public void createCompany(Company company) {
companyDAO.createCompany(company);
}
}
当我要写入数据库时:
public class Main {
public static void main(String[] args) {
ApplicationContext ctx =
new ClassPathXmlApplicationContext("spring.config.xml");
CompanyService companyService = (CompanyService) ctx.getBean("companyServiceImpl");
companyService.readCompany();
Company company = new Company();
company.setCompanyName("test1");
companyService.createCompany(company);
}
}
我有很多例外:
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error
creating bean with name 'companyDAOImpl': Injection of autowired dependencies failed; nested
exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field:
private org.hibernate.SessionFactory com.itechart.dao.impl.CompanyDAOImpl.sessionFactory; nested
exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with
name 'sessionFactory' defined in class path resource [spring.config.xml]: Invocation of init
method failed; nested exception is java.lang.NoSuchMethodError:
javax.persistence.OneToMany.orphanRemoval()Z
所以我有2个配置xml文件。冬眠
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<mapping class="model.Company" />
<mapping class="model.Department" />
</session-factory>
</hibernate-configuration>
public abstract class GenericDaoImpl<T, ID extends Serializable> {
private final Class<T> clazz;
@PersistenceContext(unitName = "persistenceUnit")
protected EntityManager entityManager;
protected GenericDaoImpl(Class<T> clazz) {
this.clazz = clazz;
}
public List<T> all() {
return entityManager.createQuery("FROM " + clazz.getName() + " a").getResultList();
}
@Transactional
public synchronized void delete(int id) {
T entity = findById(id);
entityManager.remove(entityManager.contains(entity) ? entity : entityManager.merge(entity));
}
@Transactional
public synchronized void delete(T entity) {
entityManager.remove(entityManager.contains(entity) ? entity : entityManager.merge(entity));
}
public T findById(int id) {
return entityManager.find(clazz, id);
}
@Transactional
public T findSingleResultOrNull(Query query) {
query.setMaxResults(1);
List data = query.getResultList();
if (data.size() == 1) {
return (T) data.get(0);
} else {
return null;
}
}
@Transactional
public synchronized void save(T entity) {
entityManager.persist(entityManager.contains(entity) ? entity : entityManager.merge(entity));
}
@Transactional
public synchronized void update(T entity) {
entityManager.merge(entity);
}
protected EntityManager getEntityManager() {
return entityManager;
}
protected void setEntityManager(EntityManager entityManager) {
this.entityManager = entityManager;
}
春天:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd ">
<context:component-scan base-package="dao.impl" />
<context:component-scan base-package="service.impl" />
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="configLocation">
<value>classpath:hibernate.config.xml</value>
</property>
<property name="packagesToScan" value="dao.impl"/>
</bean>
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/employee_service" />
<property name="username" value="root" />
<property name="password" value="root" />
</bean>
<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
<tx:annotation-driven transaction-manager="transactionManager" />
</beans>
类路径:hibernate.config.xml
我做错了什么?如何使用hibernate链接2个实体?
pom.xml
http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
<groupId>EmployeeService</groupId>
<artifactId>EmployeeService</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<!-- Define Spring version as a constant -->
<spring.version>3.2.0.RELEASE</spring.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>commons-dbcp</groupId>
<artifactId>commons-dbcp</artifactId>
<version>1.2.2</version>
</dependency>
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>persistence-api</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.1.9.Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.31</version>
</dependency>
</dependencies>
</project>
EmployeeService
雇员服务
1.0-快照
UTF-8
3.2.0.1发布
org.springframework
弹簧芯
${spring.version}
org.springframework
spring上下文
${spring.version}
org.springframework
德克萨斯州春季
${spring.version}
org.springframework
春季甲虫
${spring.version}
公共dbcp
公共dbcp
1.2.2
javax.persistence
持久性api
1
org.hibernate
冬眠核心
4.1.9.最终版本
mysql
mysql连接器java
5.1.31
以下错误表明您可能与jar版本存在冲突:
java.lang.NoSuchMethodError: javax.persistence.OneToMany.orphanRemoval()Z
属性需要JPA2.x。我猜您的部署中没有包含JPA2.x jar,或者您将其与一个旧的、冲突的版本一起包含
尝试将JPA 2.x jar添加到已部署应用程序的类路径中。对于Hibernate,jar的名称应该类似于Hibernate-JPA-2.x-api-1.0.x.Final.jar
。同时确保没有包含旧版本。我以前在使用Hibernate和Spring时遇到过这个问题,问题是当我尝试使用ctx时.getBean(MyClass.class)
或ctx.getBean(“MyClass”)
我会得到相同的错误。这是因为我的DAO类实现了一个接口,而这正是问题的根源
这是我的DAO类,我的其他DAO类从中继承
下面是我使用SpringMVC和Hibernate的设置
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<mapping class="model.Company" />
<mapping class="model.Department" />
</session-factory>
</hibernate-configuration>
public abstract class GenericDaoImpl<T, ID extends Serializable> {
private final Class<T> clazz;
@PersistenceContext(unitName = "persistenceUnit")
protected EntityManager entityManager;
protected GenericDaoImpl(Class<T> clazz) {
this.clazz = clazz;
}
public List<T> all() {
return entityManager.createQuery("FROM " + clazz.getName() + " a").getResultList();
}
@Transactional
public synchronized void delete(int id) {
T entity = findById(id);
entityManager.remove(entityManager.contains(entity) ? entity : entityManager.merge(entity));
}
@Transactional
public synchronized void delete(T entity) {
entityManager.remove(entityManager.contains(entity) ? entity : entityManager.merge(entity));
}
public T findById(int id) {
return entityManager.find(clazz, id);
}
@Transactional
public T findSingleResultOrNull(Query query) {
query.setMaxResults(1);
List data = query.getResultList();
if (data.size() == 1) {
return (T) data.get(0);
} else {
return null;
}
}
@Transactional
public synchronized void save(T entity) {
entityManager.persist(entityManager.contains(entity) ? entity : entityManager.merge(entity));
}
@Transactional
public synchronized void update(T entity) {
entityManager.merge(entity);
}
protected EntityManager getEntityManager() {
return entityManager;
}
protected void setEntityManager(EntityManager entityManager) {
this.entityManager = entityManager;
}
然后我有了我的Spring初始化器类
public class SpringUtil {
private static final ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring_config.xml");
public static <T extends GenericDaoImpl> T newInstance(Class<T> clazz) {
return (T) applicationContext.getBean(clazz);
}
}
公共类SpringUtil{
私有静态最终类路径XmlApplicationContext applicationContext=新类路径XmlApplicationContext(“spring_config.xml”);
公共静态T newInstance(类clazz){
return(T)applicationContext.getBean(clazz);
}
}
然后我有了我的spring\u config.xml
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
<property name="persistenceUnitName" value="persistenceUnit"/>
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" autowire="byName"/>
<tx:annotation-driven />
<context:component-scan base-package="org.mycompany.system.dao" />
然后是我的persistence.xml
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="persistenceUnit" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
<property name="hibernate.archive.autodetection" value="class"/>
<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>
<property name="hibernate.connection.url" value="YOUR_DATABASE_CONNECTION_HERE"/>
<property name="hibernate.connection.username" value="YOUR_USERNAME_HERE"/>
<property name="hibernate.connection.password" value="YOUR_PASSWORD_HERE"/>
<property name="hibernate.show_sql" value="false"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
<property name="hibernate.hbm2ddl.auto" value="update"/>
</properties>
</persistence-unit>
</persistence>
org.hibernate.ejb.HibernatePersistence
希望这对我添加到pom.xml依赖项时有所帮助:org.hibernate.javax.persistence hibernate-jpa-2.1-api 1.0.0.Final
我也有同样的例外,这可能意味着还包括jpa 1.x jar(可能通过另一个依赖项传递)。请尝试删除javax.persistence
/persistence api
/1.0
。
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
<property name="persistenceUnitName" value="persistenceUnit"/>
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" autowire="byName"/>
<tx:annotation-driven />
<context:component-scan base-package="org.mycompany.system.dao" />
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="persistenceUnit" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
<property name="hibernate.archive.autodetection" value="class"/>
<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>
<property name="hibernate.connection.url" value="YOUR_DATABASE_CONNECTION_HERE"/>
<property name="hibernate.connection.username" value="YOUR_USERNAME_HERE"/>
<property name="hibernate.connection.password" value="YOUR_PASSWORD_HERE"/>
<property name="hibernate.show_sql" value="false"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
<property name="hibernate.hbm2ddl.auto" value="update"/>
</properties>
</persistence-unit>
</persistence>