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我用netbeans向导创建了实体bean，并试图从数据库中获取数据。无论使用什么SQL查询，它都不起作用。我尝试使用，是由向导创建命名查询：语法错误解析JPA的普通查询
@NamedQuery(name = "Usr.findAll", query = "SELECT u FROM Usr u")
它返回：
Caused by: Exception [EclipseLink-8025] (Eclipse Persistence Services - 2.0.1.v20100213-r6600): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Syntax error parsing the query [Usr.findAll], line 1, column 0: unexpected token [Usr].
如果我尝试;
SELECT uid FROM usr;
我得到：
Caused by: java.lang.IllegalArgumentException: An exception occurred while creating a query in EntityManager:
Exception Description: Syntax error parsing the query [SELECT uid FROM usr;], line 0, column -1: unexpected end of query.
Internal Exception: MismatchedTokenException(-1!=78)
即使我尝试：
SELECT * FROM usr
我得到：
Caused by: Exception [EclipseLink-8025] (Eclipse Persistence Services - 2.0.1.v20100213-r6600): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Syntax error parsing the query [SELECT * FROM usr], line 1, column 7: unexpected token [*].
我对获得的数据线是：
@PersistenceContext
EntityManager em;
....
em=Persistence.createEntityManagerFactory("SchoolPU").createEntityManager();
List users = em.createQuery("SELECT * FROM usr").getResultList();
任何人都可以帮助我解决这个微不足道的问题吗？
的USR实体类：
import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Lob;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
/**
*
* @author danizmax
*/
@Entity
@Table(name = "USR")
@NamedQueries({
@NamedQuery(name = "Usr.findAll", query = "SELECT u FROM Usr u"),
@NamedQuery(name = "Usr.findByUid", query = "SELECT u FROM Usr u WHERE u.uid = :uid"),
@NamedQuery(name = "Usr.findByPassword", query = "SELECT u FROM Usr u WHERE u.password = :password"),
@NamedQuery(name = "Usr.findByFistname", query = "SELECT u FROM Usr u WHERE u.fistname = :fistname"),
@NamedQuery(name = "Usr.findByLastname", query = "SELECT u FROM Usr u WHERE u.lastname = :lastname"),
@NamedQuery(name = "Usr.findByAddress1", query = "SELECT u FROM Usr u WHERE u.address1 = :address1"),
@NamedQuery(name = "Usr.findByAddress2", query = "SELECT u FROM Usr u WHERE u.address2 = :address2"),
@NamedQuery(name = "Usr.findByPostcode", query = "SELECT u FROM Usr u WHERE u.postcode = :postcode"),
@NamedQuery(name = "Usr.findByEmail", query = "SELECT u FROM Usr u WHERE u.email = :email"),
@NamedQuery(name = "Usr.findByPhone", query = "SELECT u FROM Usr u WHERE u.phone = :phone")})
public class Usr implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@Basic(optional = false)
@Column(name = "UID", nullable = false, length = 8)
private String uid;
@Basic(optional = false)
@Column(name = "PASSWORD", nullable = false, length = 20)
private String password;
@Basic(optional = false)
@Column(name = "FISTNAME", nullable = false, length = 30)
private String fistname;
@Basic(optional = false)
@Column(name = "LASTNAME", nullable = false, length = 60)
private String lastname;
@Basic(optional = false)
@Column(name = "ADDRESS1", nullable = false, length = 100)
private String address1;
@Column(name = "ADDRESS2", length = 100)
private String address2;
@Basic(optional = false)
@Lob
@Column(name = "CITY", nullable = false)
private byte[] city;
@Basic(optional = false)
@Column(name = "POSTCODE", nullable = false, length = 10)
private String postcode;
@Column(name = "EMAIL", length = 50)
private String email;
@Column(name = "PHONE")
private Integer phone;
public Usr() {
}
public Usr(String uid) {
this.uid = uid;
}
public Usr(String uid, String password, String fistname, String lastname, String address1, byte[] city, String postcode) {
this.uid = uid;
this.password = password;
this.fistname = fistname;
this.lastname = lastname;
this.address1 = address1;
this.city = city;
this.postcode = postcode;
}
public String getUid() {
return uid;
}
public void setUid(String uid) {
this.uid = uid;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getFistname() {
return fistname;
}
public void setFistname(String fistname) {
this.fistname = fistname;
}
public String getLastname() {
return lastname;
}
public void setLastname(String lastname) {
this.lastname = lastname;
}
public String getAddress1() {
return address1;
}
public void setAddress1(String address1) {
this.address1 = address1;
}
public String getAddress2() {
return address2;
}
public void setAddress2(String address2) {
this.address2 = address2;
}
public byte[] getCity() {
return city;
}
public void setCity(byte[] city) {
this.city = city;
}
public String getPostcode() {
return postcode;
}
public void setPostcode(String postcode) {
this.postcode = postcode;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public Integer getPhone() {
return phone;
}
public void setPhone(Integer phone) {
this.phone = phone;
}
@Override
public int hashCode() {
int hash = 0;
hash += (uid != null ? uid.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 Usr)) {
return false;
}
Usr other = (Usr) object;
if ((this.uid == null && other.uid != null) || (this.uid != null && !this.uid.equals(other.uid))) {
return false;
}
return true;
}
@Override
public String toString() {
return "org.danizmax.Usr[uid=" + uid + "]";
}
}
persistance.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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_2_0.xsd">
<persistence-unit name="SchoolPU" transaction-type="JTA">
<jta-data-source>jdbc/school</jta-data-source>
<properties>
</properties>
</persistence-unit>
</persistence>
，我使用的实体类：
import java.util.Iterator;
import java.util.List;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.Persistence;
import javax.persistence.PersistenceContext;
/**
*
* @author danizmax
*/
@Stateless
public class ValidatorBean {
@PersistenceContext
EntityManager em;
public ValidatorBean() {
}
public boolean validate(String user, String pass) {
List users = em.createQuery("SELECT * FROM usr").getResultList();
Iterator it = users.iterator();
//ignore the stupid validation it's only to try out JPA
while(it.hasNext()){
Usr u = (Usr) it.next();
if(u.getUid().equals(user) && u.getPassword().equals(pass)){
return true;
}
}
return false;
}
}
UPDATE：为了公平对待你那些回答并奖励你的努力的人，现在我已经学会了技术，并在现实世界中使用它，我决定关闭这个答案，并颁发最好的答案，这是我很久以前发现自己最可能的解决方案。
我确实找到了解决方案，但不记得究竟是什么，只是它与代码中的投射有关。如果我弄清楚它到底是什么，我会把它作为答案发布。 – danizmax 2012-02-03 07:18:57