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我已經開發了使用spring mvc和hibernate的服務器程序。 我需要在MySQL表中使用max函數。 所以，我搜索了兩種方法。 一個是爲什麼數據庫沒有映射？
public void getMaxImageNumber() {
Session session = this.sessionFactory.getCurrentSession();
String hql = "select max(festival_image_number) from festival_image";
List list = session.createQuery(hql).list();
int maxNumber = ((Integer) list.get(0)).intValue();
System.out.println(maxNumber);
}
另一個是
public void getMaxImageNumber() {
DetachedCriteria maxId = DetachedCriteria.forClass(FestivalImage.class)
.setProjection(Projections.max("festival_image_number"));
List resultList = session.createCriteria(FestivalImage.class)
.add(Property.forName("festival_image_number").eq(maxId))
.list();
Iterator iter = resultList.iterator();
for (; iter.hasNext();) {
System.out.println(iter.next().toString());
}
}
當我使用第二種方法，列表是空的......我不知道爲什麼。所以，我嘗試其他方式。這是第一種方法。但是，當我嘗試這種方法時，會發生org.hibernate.hql.internal.ast.QuerySyntaxException錯誤。 我已經映射表... 請幫我..
這是模型類FestivalImage。
package kr.ac.jbnu.jinggumdari.model;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.Table;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@Entity
@Table(name="festival_image")
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class FestivalImage {
@Id
@Column(name="festival_image_number")
private String festivalImageNumber;
@Column(name="festival_image_path")
private String festivalImagePath;
@Column(name="festival_image_file_name")
private String festivalImageFileName;
@JoinColumn(name = "festival_number", table = "festival_info")
private String festivalNumber;
public FestivalImage(String festivalImageNumber, String festivalNumber,
String festivalImagePath, String festivalImageFileName) {
this.festivalImageNumber = festivalImageNumber;
this.festivalNumber = festivalNumber;
this.festivalImagePath = festivalImagePath;
this.festivalImageFileName = festivalImageFileName;
}
public String getRegionFestivalImageNumber() {
return festivalImageNumber;
}
public void setRegionFestivalImageNumber(String festivalImageNumber) {
this.festivalImageNumber = festivalImageNumber;
}
public String getFestivalNumber() {
return festivalNumber;
}
public void setFestivalNumber(String festivalNumber) {
this.festivalNumber = festivalNumber;
}
public String getFestivalImagePath() {
return festivalImagePath;
}
public void setFestivalImagePath(String festivalImagePath) {
this.festivalImagePath = festivalImagePath;
}
public String getFestivalImageFileName() {
return festivalImageFileName;
}
public void setFestivalImageFileName(String festivalImageFileName) {
this.festivalImageFileName = festivalImageFileName;
}
@Override
public String toString(){
return festivalImageNumber + "," + festivalNumber + "," + festivalImagePath + "," + festivalImageFileName;
}
}
這是servlet的context.xml中
<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd">
<!-- DispatcherServlet Context: defines this servlet's request-processing
infrastructure -->
<!-- Enables the Spring MVC @Controller programming model -->
<annotation-driven />
<!-- Handles HTTP GET requests for /resources/** by efficiently serving
up static resources in the ${webappRoot}/resources directory -->
<resources mapping="/resources/**" location="/resources/" />
<!-- Resolves views selected for rendering by @Controllers to .jsp resources
in the /WEB-INF/views directory -->
<beans:bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<beans:property name="prefix" value="/WEB-INF/views/" />
<beans:property name="suffix" value=".jsp" />
</beans:bean>
<beans:bean
class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
<beans:property name="favorPathExtension" value="true" />
<beans:property name="ignoreAcceptHeader" value="true" />
<beans:property name="mediaTypes">
<beans:map>
<beans:entry key="json" value="application/json" />
<beans:entry key="html" value="text/html" />
</beans:map>
</beans:property>
</beans:bean>
<context:component-scan base-package="kr.ac.jbnu.jinggumdari" />
<beans:bean
class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor" />
<beans:bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<beans:property name="driverClassName" value="com.mysql.jdbc.Driver" />
<beans:property name="url"
value="jdbc:mysql://localhost:3306/jinggumdari" />
<beans:property name="username" value="root" />
<beans:property name="password" value="mysql1234" />
</beans:bean>
<!-- Hibernate 4 SessionFactory Bean definition -->
<beans:bean id="hibernate4AnnotatedSessionFactory"
class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<beans:property name="dataSource" ref="dataSource" />
<beans:property name="annotatedClasses">
<beans:list>
<beans:value>kr.ac.jbnu.jinggumdari.model.Member</beans:value>
<beans:value>kr.ac.jbnu.jinggumdari.model.Festival</beans:value>
<beans:value>kr.ac.jbnu.jinggumdari.model.FestivalImage</beans:value>
</beans:list>
</beans:property>
<beans:property name="hibernateProperties">
<beans:props>
<beans:prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect
</beans:prop>
<beans:prop key="hibernate.show_sql">true</beans:prop>
</beans:props>
</beans:property>
</beans:bean>
<beans:bean id="memberDAO" class="kr.ac.jbnu.jinggumdari.DAO.MemberDAOImpl">
<beans:property name="sessionFactory"
ref="hibernate4AnnotatedSessionFactory" />
</beans:bean>
<beans:bean id="memberService"
class="kr.ac.jbnu.jinggumdari.serviceImplementation.MemberManageServiceImpl">
<beans:property name="memberDAO" ref="memberDAO"></beans:property>
</beans:bean>
<beans:bean id="festivalDAO" class="kr.ac.jbnu.jinggumdari.DAO.FestivalDAOImpl">
<beans:property name="sessionFactory"
ref="hibernate4AnnotatedSessionFactory" />
</beans:bean>
<beans:bean id="festivalService"
class="kr.ac.jbnu.jinggumdari.serviceImplementation.FestivalManageServiceImpl">
<beans:property name="festivalDAO" ref="festivalDAO"></beans:property>
</beans:bean>
<beans:bean id="festivalImageDAO" class="kr.ac.jbnu.jinggumdari.DAO.FestivalImageDAOImpl">
<beans:property name="sessionFactory"
ref="hibernate4AnnotatedSessionFactory" />
</beans:bean>
<beans:bean id="festivalImageService"
class="kr.ac.jbnu.jinggumdari.serviceImplementation.FestivalImageServiceImpl">
<beans:property name="festivalImageDAO" ref="festivalImageDAO"></beans:property>
</beans:bean>
<beans:bean id="reviewDAO" class="kr.ac.jbnu.jinggumdari.DAO.ReviewDAOImpl">
<beans:property name="sessionFactory"
ref="hibernate4AnnotatedSessionFactory" />
</beans:bean>
<beans:bean id="reviewService"
class="kr.ac.jbnu.jinggumdari.serviceImplementation.ReviewManageServiceImpl">
<beans:property name="reviewDAO" ref="reviewDAO"></beans:property>
</beans:bean>
<tx:annotation-driven transaction-manager="transactionManager" />
<beans:bean id="transactionManager"
class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<beans:property name="sessionFactory"
ref="hibernate4AnnotatedSessionFactory" />
</beans:bean>
</beans:beans>
這FestivalImageDAOImple具有getMaxImageNumber（）。
package kr.ac.jbnu.jinggumdari.DAO;
import java.util.Iterator;
import java.util.List;
import java.util.Vector;
import kr.ac.jbnu.jinggumdari.model.FestivalImage;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.criterion.DetachedCriteria;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Property;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.transaction.annotation.Transactional;
public class FestivalImageDAOImpl implements FestivalImageDAO {
private static final Logger logger = LoggerFactory
.getLogger(FestivalImageDAO.class);
private SessionFactory sessionFactory;
private boolean isSuccess;
public void setSessionFactory(SessionFactory sf) {
this.sessionFactory = sf;
}
@Override
@Transactional
public boolean addFestivalImage(FestivalImage festivalImage) {
isSuccess = false;
Session session = this.sessionFactory.getCurrentSession();
session.persist(festivalImage);
logger.info("FestivalImage saved successfully, FestivalImage Details="
+ festivalImage);
isSuccess = true;
return isSuccess;
}
@Override
@Transactional
public boolean modifyFestivalImage(FestivalImage festivalImage) {
isSuccess = false;
Session session = this.sessionFactory.getCurrentSession();
session.update(festivalImage);
logger.info("FestivalImage modified successfully, FestivalImage Details="
+ festivalImage);
isSuccess = true;
return isSuccess;
}
@Override
@Transactional
public boolean removeFestivalImage(String festivalImageNumber) {
isSuccess = false;
Session session = this.sessionFactory.getCurrentSession();
FestivalImage festivalImage = (FestivalImage) session.load(
FestivalImage.class, new String(festivalImageNumber));
if (null != festivalImage) {
session.delete(festivalImage);
}
logger.info("FestivalImage deleted successfully, festivalImageNumber details="
+ festivalImageNumber);
isSuccess = true;
return isSuccess;
}
@Override
@Transactional
public FestivalImage getFestivalImage(String festivalImageNumber) {
Session session = this.sessionFactory.getCurrentSession();
FestivalImage festivalImage = (FestivalImage) session.load(
FestivalImage.class, new String(festivalImageNumber));
logger.info("FestivalImage loaded successfully, FestivalImage details="
+ festivalImageNumber);
return festivalImage;
}
@Override
@Transactional
public Vector<FestivalImage> getFestivalImages() {
Session session = this.sessionFactory.getCurrentSession();
logger.info("FestivalImage loaded successfully");
return null;
}
@Override
@Transactional
public void getMaxImageNumber() {
Session session = this.sessionFactory.getCurrentSession();
String hql = "select max(festival_image_number) from festival_image";
List list = session.createQuery(hql).list();
int maxNumber = ((Integer) list.get(0)).intValue();
System.out.println(maxNumber);
// DetachedCriteria maxId = DetachedCriteria.forClass(FestivalImage.class)
// .setProjection(Projections.max("festival_image_number"));
// List resultList = session.createCriteria(FestivalImage.class)
// .add(Property.forName("festival_image_number").eq(maxId))
// .list();
// Iterator iter = resultList.iterator();
// for (; iter.hasNext();) {
// System.out.println(iter.next().toString());
// }
}
// @Override
// @Transactional
// public void getMaxImageNumber() {
// Session session = this.sessionFactory.getCurrentSession();
// DetachedCriteria maxId = DetachedCriteria.forClass(FestivalImage.class)
// .setProjection(Projections.max("festival_image_number"));
// List resultList =
// session.createCriteria(FestivalImage.class).add(Property.forName("festival_image_number").eq(maxId))
// .list();
// Iterator iter = resultList.iterator();
// for(;iter.hasNext();){
// System.out.println(iter.next());
// }
// // Criteria c = session.createCriteria(FestivalImage.class);
// // Order order;
// // c.addOrder(order.);
// // c.setMaxResults(1);
// // return (FestivalImage)c.uniqueResult();
// }
}
什麼實際問題？ –
堆棧跟蹤在哪裏？ – Jens