我在jpa-hibernate中有错误“无会话”

Question

我尝试通过jpa-hibernate，lazy join获取数据，但是我收到了一个错误。
我的东西：

表user_role

user_role_id    username    ROLE
2 petroff   ROLE_ADMIN

表用户

id  username    password    salt    email   profile phone   repassword 
 6 petroff     12345      ${config.salt}    petroff@еуые.com    test petroff prifile    ""  12345

零件类用户

@Entity
@Table(name = "tbl_user")
@Repassword(pass = "password", repass = "repassword")
public class User {

    @Id
    @Column(name = "id")
    private int id;
    @NotNull
    @Size(min = 2, max = 64)
    @Column(name = "username")
    private String username;
    @NotNull
    @Size(min = 2, max = 64)
    @Column(name = "password")
    private String password;
    @Column(name = "salt")
    private String salt;
    @Email
    @Column(name = "email")
    private String email;
    @NotEmpty
    @Column(name = "profile")
    private String profile;
    private String repassword;
    @OneToMany(fetch = FetchType.LAZY, mappedBy = "user")
    private Set<UserRole> userRole = new HashSet<UserRole>();

    public Set<UserRole> getUserRole() {
        return userRole;
    }

    public void setUserRole(Set<UserRole> userRole) {
        this.userRole = userRole;
    }

零件类UserRole

@Entity
@Table(name = "user_roles")
public class UserRole {

    @Id
    @Column(name = "user_role_id")
    private Integer userRoleId;
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "username", nullable = false)
    private com.blog.blog.entity.User user;
    @Column(name = "role", nullable = false, length = 45)
    private String role;

    //getter and setter methods
    public Integer getUserRoleId() {
        return userRoleId;
    }

    public void setUserRoleId(Integer userRoleId) {
        this.userRoleId = userRoleId;
    }

通话方法

@Autowired
UserService us;

@RequestMapping(value = "/test", method = RequestMethod.GET)
    public String printHello(ModelMap model, HttpSession session) {

        com.blog.blog.entity.User u = us.getByUserName("petroff");
        Set<UserRole> userRoles = u.getUserRole();
        return "hello";
    }

服务

@Service
@Transactional(readOnly = true)
public class UserServiceImpl implements UserService {

    @Autowired
    private UserRepository userRepository;
    @PersistenceContext
    private EntityManager entityManager;

    @Override
    public User addUser(User u) {
        User savedUser = userRepository.saveAndFlush(u);
        return savedUser;
    }

    @Override
    public void delete(Integer id) {
        userRepository.delete(id);
    }

    @Override
    public User editUser(User u) {
        return userRepository.saveAndFlush(u);
    }

    @Override
    public List<User> getAll() {
        return userRepository.findAll();
    }

    @Override
    public User getByUserName(String name) {
        return userRepository.findByUserName(name);
    }    
}

配置文件

<?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:p="http://www.springframework.org/schema/p"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:jpa="http://www.springframework.org/schema/data/jpa"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
           http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd">
    <bean id="propertyConfigurer"
          class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"
          p:location="/WEB-INF/config.properties"/>
    <context:component-scan base-package="com.blog.blog.service.impl"/>
    <jpa:repositories base-package="com.blog.blog.repositories"/>

    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="${jdbc.drivers}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>

    <bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
        <property name="showSql" value="true"/>
        <property name="generateDdl" value="true"/>
        <property name="database" value="MYSQL"/>
    </bean>

    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="jpaVendorAdapter" ref="jpaVendorAdapter"/>
        <!-- spring based scanning for entity classes-->
        <property name="packagesToScan" value="com.blog.blog.entity"/>
    </bean>
    <tx:annotation-driven/>
    <bean id="userDetailsService"
          class="com.blog.blog.service.impl.UserDetailsImpl">
    </bean>
    <import resource="spring-security.xml"/>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"/>

    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="get*" read-only="true"/>
            <tx:method name="find*" read-only="true"/>
            <tx:method name="*"/>
        </tx:attributes>
    </tx:advice>

    <bean id="sessionFactory" class="org.springframework.orm.jpa.vendor.HibernateJpaSessionFactoryBean">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>

    <aop:config>
        <aop:pointcut id="userServicePointCut"
                      expression="execution(* com.blog.blog.service.impl.*Service.*(..))"/>
        <aop:advisor advice-ref="txAdvice" pointcut-ref="userServicePointCut"/>

    </aop:config>
</beans>

我得到用户obj

 com.blog.blog.entity.User u = us.getByUserName("petroff");

但是当我打电话的时候

 Set<UserRole> userRoles = u.getUserRole();

我收到一个错误：

Exception occurred in target VM: failed to lazily initialize a collection of role: com.blog.blog.entity.User.userRole, could not initialize proxy - no Session 
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.blog.blog.entity.User.userRole, could not initialize proxy - no Session
    at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:566)
    at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:186)
    at org.hibernate.collection.internal.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:137)
    at org.hibernate.collection.internal.PersistentSet.size(PersistentSet.java:156)
    at com.blog.blog.controller.Main.printHello(Main.java:37)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
    at

Answer 1

如果要在调用者端使用它，则需要在服务中初始化延迟集合。 尝试这个

@Override
public User getByUserName(String name) {
    User u = userRepository.findByUserName(name);
    Hibernate.initialize(u.getUserRole());
    return u;
}

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