無法寫入內容：無法懶洋洋地初始化角色的集合使用OpenEntityManagerInViewFilter

Question

所以我有這樣兩類：

樣品

@Entity 
@Table(name="sample") 
public class Sample implements Serializable { 

@Id 
@GeneratedValue 
@Column(name="sample_id") 
private Long sample_id; 
@Column(name="id") 
private String id; 
@Column(name="description") 
private String description; 
@ManyToOne 
@JoinColumn(name="dna_study_id") 
private DNA_Study study; 
...Getters and setters ... 

DNA_Study

@Entity 
@Table(name = "dna_study") 
public class DNA_Study implements Serializable { 

@Id 
@GeneratedValue 
@Column(name="dna_study_id") 
private Long id; 
@Column(name="name") 
private String name; 
@Column(name="description") 
private String description; 
@Column(name="date") 
private Date date; 
@OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL) 
@JoinColumn(name = "dna_study_id") 
private List<Sample> samples; 

我想從我的數據庫中獲得所有的DNA_Study，有這個DAO：

@Repository 
public interface DNA_StudyDAO extends CrudRepository<DNA_Study, Long>{ } 

這RestController：

@RestController 
public class AnalysisController { 

    ClassPathXmlApplicationContext context; 

    @CrossOrigin 
    @RequestMapping("/getanalysis") 
    public ArrayList<DNA_Study> getAnalysis() { 

     context = new ClassPathXmlApplicationContext("applicationContext.xml"); 
     DNA_StudyDAO dao = context.getBean(DNA_StudyDAO.class); 
     return (ArrayList<DNA_Study>) dao.findAll(); 
    } 

，當我把它稱爲我得到 「無法寫入內容：無法懶洋洋地初始化角色集」 我試着修改我的DAO，所以方法findAll（）更改爲：

@Override 
@Query("select d from DNA_Study d join fetch d.samples") 
Iterable<DNA_Study> findAll(); 

使用t他沒有例外被拋出，但調用方法創建了一個無限循環，因爲創建一個DNA_Study意味着加載它的樣本，每個樣本加載它的DNA_Study等，以便它打破。所以，我想我需要添加一個OpenEntityManagerInViewFilter和撤消覆蓋到的findAll（），嘗試添加到我的SpringBootServletInitializer類：

@Override 
public void onStartup(ServletContext servletContext) throws ServletException 
{ 
    AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext(); 
    rootContext.register(Application.class); 
    rootContext.setServletContext(servletContext); 
    ServletRegistration.Dynamic dispatcher = servletContext.addServlet("dispatcher", new DispatcherServlet(rootContext)); 
    dispatcher.setLoadOnStartup(1); 
    dispatcher.addMapping("/"); 

    FilterRegistration.Dynamic filter = servletContext.addFilter("openEntityManagerInViewFilter", OpenEntityManagerInViewFilter.class); 
    filter.setInitParameter("singleSession", "true"); 
    filter.addMappingForServletNames(null, true, "dispatcher"); 
    servletContext.addListener(new ContextLoaderListener(rootContext)); 
} 

但是，當我打這個電話，我仍然得到「未能懶洋洋地初始化角色集合「

我應該如何正確添加OpenEntityManagerInViewFilter？

擴展 SpringBootServletInitializer

---

編輯

類：

@Override 
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) { 
     return application.sources(GemDomusServerApplication.class); 
    } 

    @Override 
    public void onStartup(ServletContext servletContext) throws ServletException 
    { 
     AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext(); 
     rootContext.register(Application.class); 
     rootContext.setServletContext(servletContext); 
     ServletRegistration.Dynamic dispatcher = servletContext.addServlet("dispatcher", new DispatcherServlet(rootContext)); 
     dispatcher.setLoadOnStartup(1); 
     dispatcher.addMapping("/"); 
     FilterRegistration.Dynamic filter = servletContext.addFilter("openEntityManagerInViewFilter", OpenEntityManagerInViewFilter.class); 
     filter.setInitParameter("singleSession", "true"); 
     filter.setInitParameter("entityManagerFactoryBeanName", "entityManagerFactory"); 
     filter.setInitParameter("flushMode", "auto"); 
     filter.addMappingForServletNames(null, true, "dispatcher"); 
     servletContext.addListener(new ContextLoaderListener(rootContext)); 
     servletContext.addListener(new RequestContextListener()); 
    } 

    public static void main(String[] args) { 

     SpringApplication.run(GemDomusServerApplication.class, args); 
    } 

applicationContext.xml的豆類參與

<bean id="entityManagerFactory" 
     class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> 
     <property name="dataSource" ref="dataSource" /> 
     <property name="persistenceUnitName" value="jpaData" /> 
     <property name="jpaVendorAdapter"> 
      <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" /> 
     </property> 
     <property name="jpaProperties"> 
      <props> 
       <prop key="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</prop> 
       <prop key="hibernate.show_sql">true</prop> 
       <prop key="hibernate.format_sql">true</prop> 
       <prop key="hibernate.hbm2ddl.auto">update</prop> 
      </props> 
     </property> 
    </bean> 

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> 
     <property name="entityManagerFactory" ref="entityManagerFactory" /> 
    </bean> 
<bean id="dataSource" 
     class="org.springframework.jdbc.datasource.DriverManagerDataSource"> 
     <property name="driverClassName"> 
      <value>org.postgresql.Driver</value> 
     </property> 
     <property name="url"> 
      <value>**</value> 
     </property> 
     <property name="username"> 
      <value>**</value> 
     </property> 
     <property name="password"> 
      <value>**</value> 
     </property> 
    </bean> 

周

的persistence.xml

<?xml version="1.0" encoding="UTF-8"?> 
<persistence version="1.0" 
    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_1_0.xsd"> 

    <persistence-unit name="jpaData"/> 

</persistence> 

Answer 1

嗯，試圖終於在這工作： 使渴望初始化展位集合（樣品和DNA_Study和改變AnalysisController到：

@CrossOrigin 
    @RequestMapping("/getanalysis") 
    public JsonArray getAnalysis() { 

     context = new ClassPathXmlApplicationContext("applicationContext.xml"); 
     DNA_StudyDAO dao = context.getBean(DNA_StudyDAO.class); 
     ArrayList<DNA_Study> result = (ArrayList<DNA_Study>) dao.findAll(); 
     JsonArrayBuilder datasourcesBuilder = Json.createArrayBuilder(); 
     for(DNA_Study study : result) { 
      datasourcesBuilder 
      .add(Json.createObjectBuilder() 
       .add("name", study.getName()) 
       .add("description", study.getDescription()) 
       .add("size", String.valueOf(study.getSamples().size()))); 
     } 
     return datasourcesBuilder.build(); 
} 

找不到這樣做的懶惰初始化

Answer 2

你的問題看起來非常相似，這一個Lazy Initialisation with OpenEntityManagerInViewFilter?

另一種選擇，我的首選，是調用休眠。初始化（對象）的DAO內部或經理包裝你的DAO與@Transactional

註釋