JPA:如何使用@NamedQuery从不同的DB2模式中指定表。Schema.Table不能是FROM子句的第一个声明

Question

当从邮递员发送GET请求测试我的端点时，我遇到了一个问题。以前，同一个NamedQueries只使用一个模式，所以不需要区分。现在，我已经更改为运行在本地Docker实例中的DB2，并且正在使用Maven来运行来创建端点。我收到以下错误。我需要创建一个带有实体映射的orm.xml文件，还是需要做一些其他的事情来解决这个问题？如果可能的话，我更希望在没有更多xml文件的情况下这样做。

邮差：

因为“>"javax.persistence.EntityManager.createNamedQuery(String，”是空的，所以

错误500: java.lang.NullPointerException:无法调用java.lang.Class)

Maven：

org.eclipse.persistence.jpa.PersistenceProvider信息提供程序:当它试图为jpa单元持久性单元创建容器实体管理器工厂时，

持久化提供程序发生了错误。发生以下错误:异常EclipseLink-28019：EclipseLink-28019信息异常描述:部署PersistenceUnit jpa失败。关闭此PersistenceUnit的所有工厂。

内部异常:异常EclipseLink-0：org.eclipse.persistence.exceptions.JPQLException

信息异常描述:编译问题，从Sankofa.Users u中选择u。

信息'Sankofa.Users u‘不能是FROM子句的第一个声明。

UserDao

package dao;

import java.util.List;
import java.util.concurrent.TimeoutException;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import org.hyperledger.fabric.gateway.ContractException;

import javax.enterprise.context.RequestScoped;
import models.*;

@RequestScoped
public class UserDao {
    
//DB2 Methods
    @PersistenceContext(name = "jpa-unit")
    private EntityManager em;

    public void createUser(Users user){
        em.persist(user);
    }
    
    public Users readUser(int userID){
        return em.find(Users.class, userID);
    }
    //NEED TO DO set return limit to 20
    public List<Users> readAllUsers(){
        return em.createNamedQuery("Users.findAll", Users.class).getResultList();
    }

    public void updateUser(Users user){
        em.merge(user);
    }

    public void deleteUser(Users userID){
        em.remove(userID);
    }

    public List<Users> findUser(String email){
        return em.createNamedQuery("Users.findUser", Users.class)
            .setParameter("email", email)
            .getResultList(); 
    }

    public void createHistory(History hist){
        em.persist(hist);
    }
    //wait this doesnt do anything? 
    public Users readHistory(int userID){
        return em.find(Users.class, userID);
    }

    public List<History> readAllHistory(){
        return em.createNamedQuery("History.findAll", History.class).getResultList();
    }
}

用户

package models;

import java.util.HashSet;
import java.util.Objects;
import java.util.Set;

import javax.json.Json;
import javax.json.JsonArrayBuilder;
import javax.json.JsonObject;
import javax.json.JsonObjectBuilder;
import javax.persistence.*;
import java.time.LocalDate;

@Entity
@Table(name = "Users")
@NamedQueries({
    @NamedQuery(name = "Users.findAll", query = "SELECT u FROM Users u"),
    @NamedQuery(name = "Users.findUser", query = "SELECT usr FROM Users usr WHERE usr.email = :email")
})
public class Users {

    private static JsonObjectBuilder builder = Json.createObjectBuilder();

    @GeneratedValue(strategy = GenerationType.AUTO)
    @Id
    @Column(name = "userId")
    private int id;

    @Column(name = "firstName")
    private String firstName;
    @Column(name = "lastName")
    private String lastName;
    @Column(name = "gender")
    private String gender;
    @Column(name = "address")
    private String address;
    @Column(name = "email")
    private String email;
    @Column(name = "password")
    private String password;
    @Column(name = "dateOfBirth")
    private LocalDate dateOfBirth;

Persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.2"
    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_2.xsd">
    <persistence-unit name="jpa-unit" transaction-type="JTA">
        <mapping-file>orm.xml</mapping-file>
        
        <properties>
            <!-- Connection Specific -->
            <property name="hibernate.dialect" value="org.hibernate.dialect.DB2Dialect"/>
            
            <property name="javax.persistence.schema-generation.database.action" value="create" />
            <property name="javax.persistence.schema-generation.create-database-schemas" value="true" />
            <property name="javax.persistence.schema-generation.scripts.action" value="create" />
            <property name="javax.persistence.schema-generation.scripts.create-target" value="create.ddl"/>

        </properties>
    </persistence-unit>
</persistence>

Server.xml

<server description="Obdoblock REST Server">
    <featureManager>
        <feature>jaxrs-2.1</feature>
        <feature>openapi-3.1</feature>
        <feature>jpa-2.2</feature>
        <feature>cdi-2.0</feature>
    </featureManager>
  
    <httpEndpoint 
        httpPort="${default.http.port}" 
        httpsPort="${default.https.port}"
        id="defaultHttpEndpoint" 
        host="*" 
    />

    <webApplication 
        location="hyperledger-api.war" 
        contextRoot="${app.context.root}"
    />
    
    <!-- DB2 Library Configuration -->
    <library id="DB2JCCLib">
        <file name="${shared.resource.dir}/jcc-11.5.6.0" />
    </library>
    
    
    <dataSource id="DefaultDataSource" jndiName="jdbc/db2">
        <jdbcDriver libraryRef="jdbcLib"/>
        <properties.db2.jcc
            databaseName="testdb"
            serverName="localhost" 
            portNumber="50000"
            user="****" password="****"
        />
    </dataSource>
</server>

版本：

11.5.6

• Maven：
• docker : 20.10.8，构建3967b7
• DB2: ibm/db2
• 映像版本 3.8.3
  • Java: JDK 14.0.2

如果需要更多的细节，我很乐意提供。谢谢你，迪伦

Answer 1

如何使用@NamedQuery从不同的DB2模式指定表

AFAIK，您不能在查询级别配置架构值。在该实体下定义的所有命名查询都将针对同一模式执行。

1. 数据库模式可以通过orm.xml映射文件在持久性单元级别设置：

orm.xml

<实体-映射…> Sankofa。。。

persistence.xml

<持久性.> orm.xml

1. For EclipseLink，您可以配置SessionCustomizer类

公共类org.eclipse.persistence.config.SessionCustomizer实现了{@覆盖公共void (会话会话)抛出异常{ session.getLogin().setTableQualifier("Sankofa")；}}

persistence.xml

<持久性.>

@

• 注释具有一个“模式”元素，用于在实体级别配置模式

@Table(name = "Users"，schema = "Sankofa")