Question

我无法弄清楚我做错了什么。我正在学习JPA映射到关系数据库，通过在网上学习一些教程，但找不到一个直截了当的教程。当我运行我的项目时，它给了我一个错误。我想这是坚持em.persist();。如果我评论该行，所有看起来都很好，没有错误，但显然没有数据写入表。这是我的代码：

persistence.xml（生成，未触及）

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" 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">
    <persistence-unit name="RESTappPU" transaction-type="RESOURCE_LOCAL">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <class>restapp.entities.ContactList</class>
        <properties>
            <property name="javax.persistence.jdbc.url" value="jdbc:postgresql://localhost:5432/postgres"/>
            <property name="javax.persistence.jdbc.user" value="postgres"/>
            <property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver"/>
            <property name="javax.persistence.jdbc.password" value="postgres"/>
        </properties>
    </persistence-unit>
</persistence>

实体类（已生成，未触及） - 我是否需要在此处添加一些额外的“关系”方法？

package restapp.entities;

imports [...]

@Entity
@Table(name = "ContactList")
@NamedQueries({
    @NamedQuery(name = "ContactList.findAll", query = "SELECT c FROM ContactList c"),
    @NamedQuery(name = "ContactList.findByFirstname", query = "SELECT c FROM ContactList c WHERE c.firstname = :firstname"),
    @NamedQuery(name = "ContactList.findByLastname", query = "SELECT c FROM ContactList c WHERE c.lastname = :lastname"),
    @NamedQuery(name = "ContactList.findByMobile", query = "SELECT c FROM ContactList c WHERE c.mobile = :mobile"),
    @NamedQuery(name = "ContactList.findByEmail", query = "SELECT c FROM ContactList c WHERE c.email = :email")})
public class ContactList implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @Basic(optional = false)
    @Column(name = "firstname")
    private String firstname;
    @Column(name = "lastname")
    private String lastname;
    @Basic(optional = false)
    @Column(name = "mobile")
    private String mobile;
    @Column(name = "email")
    private String email;

    // constructors
    public ContactList() {
    }

    public ContactList(String firstname) {
        this.firstname = firstname;
    }

    public ContactList(String firstname, String mobile) {
        this.firstname = firstname;
        this.mobile = mobile;
    }

    public ContactList(String firstname, String lastname, String mobile, String email) {
        this.firstname = firstname;
        this.lastname = lastname;
        this.mobile = mobile;
        this.email = email;
    }

    // getter's and setter's
    public String getFirstname() {
        return firstname;
    }

    public void setFirstname(String firstname) {
        this.firstname = firstname;
    }

    public String getLastname() {
        return lastname;
    }

    public void setLastname(String lastname) {
        this.lastname = lastname;
    }

    public String getMobile() {
        return mobile;
    }

    public void setMobile(String mobile) {
        this.mobile = mobile;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    // Is something like this what it needs?
    //    @OneToOne(cascade=CascadeType.PERSIST)
    //    private Address address;

    //    @OneToMany(cascade=ALL, mappedBy="customer")
    //    public Collection<Order> getOrders() {
    //        return orders;
    //    }


    @Override
    public String toString() {
        return "\n\n\n\n[firstname: " + firstname + "]\n"
                + "[lastname: " + lastname + "]\n"
                + "[mobile: " + mobile + "]\n"
                + "[email: " + email + "]\n\n\n\n";
    }

}

Java App Class

package restapp;

imports [...]

public class RESTapp {

    private static EntityManagerFactory emf;
    private static EntityManager em;

    public static void main(String[] args) {
        // Create EntityManagerFactory for persistent unit named "pu1" to be used in this test
        emf = Persistence.createEntityManagerFactory("RESTappPU");

        // Persist the customer
        // em.persist(list0);
        // Persist all entities
        createTransactionalEntityManager();
        System.out.println("Inserting Customer and Orders... " + insert());
        closeTransactionalEntityManager();
    }

    private static String insert() {
        // Create new contact
        ContactList list0 = new ContactList();
        list0.setFirstname("John");
        list0.setLastname("Doe");
        list0.setMobile("+351 91 546 33 21");
        list0.setEmail("jdoe@fakemail.com");

        // Create another contact
        ContactList list1 = new ContactList("Jane", "Something", "+351 96 924 14 29", "jsomething@fakemail.com");

        list0.toString();

//        em.persist(list0);
        em.persist(list0);

        return "OK";
    }

    private static void createTransactionalEntityManager() {

        // Create a new EntityManager
        em = emf.createEntityManager();

        // Begin transaction
        em.getTransaction().begin();
    }

    private static void closeTransactionalEntityManager() {

        // Commit the transaction
        em.getTransaction().commit();

        // Close this EntityManager
        em.close();
    }
}

当我运行我的项目时：

run:
[EL Info]: 2015-06-03 18:30:17.315--ServerSession(1798636297)--EclipseLink, version: Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd
[EL Info]: connection: 2015-06-03 18:30:17.689--ServerSession(1798636297)--file:/home/rsousa/NetBeansProjects/RESTapp/build/classes/_RESTappPU login successful
Inserting Customer and Orders... OK
[EL Warning]: 2015-06-03 18:30:17.794--UnitOfWork(683523720)--Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: org.postgresql.util.PSQLException: ERROR: relation "contactlist" does not exist
  Position: 13
Error Code: 0
Call: INSERT INTO ContactList (firstname, email, lastname, mobile) VALUES (?, ?, ?, ?)
    bind => [4 parameters bound]
Query: InsertObjectQuery(



[firstname: John]
[lastname: Doe]
Exception in thread "main" javax.persistence.RollbackException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.DatabaseException
[mobile: +351 91 546 33 21]
Internal Exception: org.postgresql.util.PSQLException: ERROR: relation "contactlist" does not exist
[email: jdoe@fakemail.com]



)
  Position: 13
Error Code: 0
Call: INSERT INTO ContactList (firstname, email, lastname, mobile) VALUES (?, ?, ?, ?)
    bind => [4 parameters bound]
Query: InsertObjectQuery(



[firstname: John]
[lastname: Doe]
[mobile: +351 91 546 33 21]
[email: jdoe@fakemail.com]



)
    at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:157)
    at restapp.RESTapp.closeTransactionalEntityManager(RESTapp.java:66)
    at restapp.RESTapp.main(RESTapp.java:32)
Caused by: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: org.postgresql.util.PSQLException: ERROR: relation "contactlist" does not exist
  Position: 13
Error Code: 0
Call: INSERT INTO ContactList (firstname, email, lastname, mobile) VALUES (?, ?, ?, ?)
    bind => [4 parameters bound]
Query: InsertObjectQuery(



[firstname: John]
[lastname: Doe]
[mobile: +351 91 546 33 21]
[email: jdoe@fakemail.com]



)
    at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:340)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.processExceptionForCommError(DatabaseAccessor.java:1611)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect(DatabaseAccessor.java:898)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeNoSelect(DatabaseAccessor.java:962)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.basicExecuteCall(DatabaseAccessor.java:631)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeCall(DatabaseAccessor.java:558)
    at org.eclipse.persistence.internal.sessions.AbstractSession.basicExecuteCall(AbstractSession.java:2002)
    at org.eclipse.persistence.sessions.server.ClientSession.executeCall(ClientSession.java:298)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:242)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:228)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.insertObject(DatasourceCallQueryMechanism.java:377)
    at org.eclipse.persistence.internal.queries.StatementQueryMechanism.insertObject(StatementQueryMechanism.java:165)
    at org.eclipse.persistence.internal.queries.StatementQueryMechanism.insertObject(StatementQueryMechanism.java:180)
    at org.eclipse.persistence.internal.queries.DatabaseQueryMechanism.insertObjectForWrite(DatabaseQueryMechanism.java:489)
    at org.eclipse.persistence.queries.InsertObjectQuery.executeCommit(InsertObjectQuery.java:80)
    at org.eclipse.persistence.queries.InsertObjectQuery.executeCommitWithChangeSet(InsertObjectQuery.java:90)
    at org.eclipse.persistence.internal.queries.DatabaseQueryMechanism.executeWriteWithChangeSet(DatabaseQueryMechanism.java:301)
    at org.eclipse.persistence.queries.WriteObjectQuery.executeDatabaseQuery(WriteObjectQuery.java:58)
    at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:899)
    at org.eclipse.persistence.queries.DatabaseQuery.executeInUnitOfWork(DatabaseQuery.java:798)
    at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWorkObjectLevelModifyQuery(ObjectLevelModifyQuery.java:108)
    at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWork(ObjectLevelModifyQuery.java:85)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2896)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1804)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1786)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1737)
    at org.eclipse.persistence.internal.sessions.CommitManager.commitNewObjectsForClassWithChangeSet(CommitManager.java:226)
    at org.eclipse.persistence.internal.sessions.CommitManager.commitAllObjectsWithChangeSet(CommitManager.java:125)
    at org.eclipse.persistence.internal.sessions.AbstractSession.writeAllObjectsWithChangeSet(AbstractSession.java:4207)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabase(UnitOfWorkImpl.java:1441)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet(UnitOfWorkImpl.java:1531)
    at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.commitRootUnitOfWork(RepeatableWriteUnitOfWork.java:277)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitAndResume(UnitOfWorkImpl.java:1169)
    at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:132)
    ... 2 more
Caused by: org.postgresql.util.PSQLException: ERROR: relation "contactlist" does not exist
  Position: 13
    at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2157)
    at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1886)
    at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:255)
    at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:555)
    at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:417)
    at org.postgresql.jdbc2.AbstractJdbc2Statement.executeUpdate(AbstractJdbc2Statement.java:363)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect(DatabaseAccessor.java:890)
    ... 33 more
Java Result: 1
BUILD SUCCESSFUL (total time: 3 seconds)

IDE： NetBeans | DB： PostGreSQL | 持久性： EclipseLink JPA

Answer 1

Postgresql将非双引号的表名和列名转换为小写。变化

@Table(name = "ContactList")

到

@Table(name = "contactlist")

Answer 2

在我的情况下，问题不是精确的架构-可以在类的注释中提供：

@Table(name="...", schema="...")

Answer 3

您可以在application.properties中使用此配置：

spring.jpa.hibernate.naming.implicit-strategy = org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyJpaImpl spring.jpa.hibernate.naming.physical-strategy = org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl

Answer 4

我遇到了类似的问题，但就我而言，在查询中，我必须在表名前加上模式名称，因为我的数据库具有多个模式，并且我使用的是本机查询。

JPA错误：关系不存在

4 个答案: