早上好
我使用 Eclipse 链接和 JPA，我想测试一个小的本地查询，但我有一个错误。你能帮帮我吗，我在这个网站和其他网站上搜索过，但没有找到解决方案。谢谢你。
实体类
package entites;
import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;
/**
*
* @author Minoucha
*/
@Entity
@Table(name = "protocol")
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "Protocol.findAll", query = "SELECT p FROM Protocol p"),
@NamedQuery(name = "Protocol.findByProtocolid", query = "SELECT p FROM Protocol p WHERE p.protocolid = :protocolid"),
@NamedQuery(name = "Protocol.findByProtocolname", query = "SELECT p FROM Protocol p WHERE p.protocolname = :protocolname")})
public class Protocol implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "protocolid")
private Integer protocolid;
@Size(max = 64)
@Column(name = "protocolname")
private String protocolname;
public Protocol() {
}
public Protocol(Integer protocolid) {
this.protocolid = protocolid;
}
public Integer getProtocolid() {
return protocolid;
}
public void setProtocolid(Integer protocolid) {
this.protocolid = protocolid;
}
public String getProtocolname() {
return protocolname;
}
public void setProtocolname(String protocolname) {
this.protocolname = protocolname;
}
@Override
public int hashCode() {
int hash = 0;
hash += (protocolid != null ? protocolid.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof Protocol)) {
return false;
}
Protocol other = (Protocol) object;
if ((this.protocolid == null && other.protocolid != null) || (this.protocolid != null && !this.protocolid.equals(other.protocolid))) {
return false;
}
return true;
}
@Override
public String toString() {
return "entites.Protocol[ protocolid=" + protocolid + " ]";
}
}
主班
package main;
import java.util.Iterator;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
import javax.persistence.Query;
/**
*
* @author Minoucha
*/
public class Main {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
EntityManagerFactory emf = Persistence.createEntityManagerFactory("TestRestLast3PU");
EntityManager em = emf.createEntityManager();
try {
EntityTransaction entr = em.getTransaction();
entr.begin();
Query query = em.createNativeQuery("SELECT protocolname FROM protocol");
List stList = query.getResultList();
Iterator stIterator = stList.iterator();
while (stIterator.hasNext()) {
System.out.print("pname:" + stIterator.next());
System.out.println();
}
entr.commit();
} finally {
em.close();
}
}
}
错误 ：
run:
avr. 16, 2013 12:34:24 PM org.hibernate.validator.internal.util.Version <clinit>
INFO: HV000001: Hibernate Validator 4.3.0.Final
[EL Warning]: 2013-04-16 12:34:24.756--ServerSession(8630548)--PersistenceUnitInfo TestTP3RestPU has transactionType RESOURCE_LOCAL and therefore jtaDataSource will be ignored
[EL Info]: 2013-04-16 12:34:24.776--ServerSession(8630548)--EclipseLink, version: Eclipse Persistence Services - 2.3.2.v20111125-r10461
[EL Severe]: 2013-04-16 12:34:24.789--ServerSession(8630548)--Exception [EclipseLink-4021] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.DatabaseException
Exception in thread "main" javax.persistence.PersistenceException: Exception [EclipseLink-4021] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [null], user [null] and URL [null]. Verify that you have set the expected driver class and URL. Check your login, persistence.xml or sessions.xml resource. The jdbc.driver property should be set to a class that is compatible with your database platform
Exception Description: Unable to acquire a connection from driver [null], user [null] and URL [null]. Verify that you have set the expected driver class and URL. Check your login, persistence.xml or sessions.xml resource. The jdbc.driver property should be set to a class that is compatible with your database platform
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:517)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession(EntityManagerFactoryDelegate.java:188)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl(EntityManagerFactoryDelegate.java:277)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:294)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:272)
at main.Main.main(Main.java:23)
Caused by: Exception [EclipseLink-4021] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [null], user [null] and URL [null]. Verify that you have set the expected driver class and URL. Check your login, persistence.xml or sessions.xml resource. The jdbc.driver property should be set to a class that is compatible with your database platform
at org.eclipse.persistence.exceptions.DatabaseException.unableToAcquireConnectionFromDriverException(DatabaseException.java:376)
at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:91)
at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:584)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:206)
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:488)
... 5 more
Java Result: 1