我面临一个奇怪的类型转换错误（编译时错误） 一旦我从旅程表中检索数据，它就会抛出异常，因为它无法识别从列表中获取的对象。
我不知道为什么会这样抱怨，作为对象，已经是旅行类型了，我列出了一个用“Journey”类型模板化的列表，每个记录都应该是旅程。
"INFO: HHH000397: Using ASTQueryTranslatorFactory
Exception in thread "main" java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to de.db.journeyTracker.model.journey
"
public static void findalljourney(Session session )
{
String qryAllJourney = "SELECT j.id , j.operatingday, j.linename, j.scheduledeparture, j.scheduledeparturestopname FROM journey j";
Query query = session.createQuery(qryAllJourney);
List<journey> allJourney;
allJourney = query.list();
for (int i = 0; i < allJourney.size(); i++)
{
String JourneyId = allJourney.get(i).getJourneyid().toString(); /// TypeCast Exception Occured...
}
以下是旅程的Model类。
public class journey
{
int id ;
String journeyid ;
String linename ;
Date operatingday ;
Date realtimearrival;
String realtimearrivalstopname;
String realtimearrivalstopnumber ;
Date realtimedeparture ;
String realtimedeparturestopname ;
String realtimedeparturestopnumber;
Date schedulearrival ;
String schedulearrivalstopname ;
String schedulearrivalstopnumber ;
Date scheduledeparture ;
String scheduledeparturestopname ;
String scheduledeparturestopnumber ;
int arrivaldelay ;
String direction ;
String journeyoperator ;
String schedulevehicletype ;
String vehicleid ;
Double distancerealtime;
int maximumspeedrealtime ;
Boolean calledatallstops ;
int departuredelay ;
int maximumdelay;
int minimumdelay ;
String phonenumber ;
int comment_id ;
Boolean arrivaldelayprojection ;
Boolean departuredelayprojection;
Boolean maximumdelayprojection ;
Boolean maximumspeedrealtimedataincomplete;
Boolean minmaxdelaydataincomplete ;
Boolean minimumdelayprojection ;
Boolean realtimearrivalprojection ;
Boolean realtimedepartureprojection ;
}
以下是与上述旅程模型对应的hibernate配置文件
<?xml version="1.0"?>
<hibernate-mapping>
<class name="de.db.journeyTracker.model.journey" table="JOURNEY">
<id name="id" type="int">
<column name="ID" />
<generator class="assigned" />
</id>
<property name="journeyid" type="java.lang.String">
<column name="JOURNEYID" />
</property>
<property name="linename" type="java.lang.String">
<column name="LINENAME" />
</property>
<property name="operatingday" type="java.util.Date">
<column name="OPERATINGDAY" />
</property>
<property name="realtimearrival" type="java.util.Date">
<column name="REALTIMEARRIVAL" />
</property>
<property name="realtimearrivalstopname" type="java.lang.String">
<column name="REALTIMEARRIVALSTOPNAME" />
</property>
<property name="realtimearrivalstopnumber" type="java.lang.String">
<column name="REALTIMEARRIVALSTOPNUMBER" />
</property>
<property name="realtimedeparture" type="java.util.Date">
<column name="REALTIMEDEPARTURE" />
</property>
<property name="realtimedeparturestopname" type="java.lang.String">
<column name="REALTIMEDEPARTURESTOPNAME" />
</property>
<property name="realtimedeparturestopnumber" type="java.lang.String">
<column name="REALTIMEDEPARTURESTOPNUMBER" />
</property>
<property name="schedulearrival" type="java.util.Date">
<column name="SCHEDULEARRIVAL" />
</property>
<property name="schedulearrivalstopname" type="java.lang.String">
<column name="SCHEDULEARRIVALSTOPNAME" />
</property>
<property name="schedulearrivalstopnumber" type="java.lang.String">
<column name="SCHEDULEARRIVALSTOPNUMBER" />
</property>
<property name="scheduledeparture" type="java.util.Date">
<column name="SCHEDULEDEPARTURE" />
</property>
<property name="scheduledeparturestopname" type="java.lang.String">
<column name="SCHEDULEDEPARTURESTOPNAME" />
</property>
<property name="scheduledeparturestopnumber" type="java.lang.String">
<column name="SCHEDULEDEPARTURESTOPNUMBER" />
</property>
<property name="arrivaldelay" type="int">
<column name="ARRIVALDELAY" />
</property>
<property name="direction" type="java.lang.String">
<column name="DIRECTION" />
</property>
<property name="journeyoperator" type="java.lang.String">
<column name="JOURNEYOPERATOR" />
</property>
<property name="schedulevehicletype" type="java.lang.String">
<column name="SCHEDULEVEHICLETYPE" />
</property>
<property name="vehicleid" type="java.lang.String">
<column name="VEHICLEID" />
</property>
<property name="distancerealtime" type="java.lang.Double">
<column name="DISTANCEREALTIME" />
</property>
<property name="maximumspeedrealtime" type="int">
<column name="MAXIMUMSPEEDREALTIME" />
</property>
<property name="calledatallstops" type="java.lang.Boolean">
<column name="CALLEDATALLSTOPS" />
</property>
<property name="departuredelay" type="int">
<column name="DEPARTUREDELAY" />
</property>
<property name="maximumdelay" type="int">
<column name="MAXIMUMDELAY" />
</property>
<property name="minimumdelay" type="int">
<column name="MINIMUMDELAY" />
</property>
<property name="phonenumber" type="java.lang.String">
<column name="PHONENUMBER" />
</property>
<property name="comment_id" type="int">
<column name="COMMENT_ID" />
</property>
<property name="arrivaldelayprojection" type="java.lang.Boolean">
<column name="ARRIVALDELAYPROJECTION" />
</property>
<property name="departuredelayprojection" type="java.lang.Boolean">
<column name="DEPARTUREDELAYPROJECTION" />
</property>
<property name="maximumdelayprojection" type="java.lang.Boolean">
<column name="MAXIMUMDELAYPROJECTION" />
</property>
<property name="maximumspeedrealtimedataincomplete" type="java.lang.Boolean">
<column name="MAXIMUMSPEEDREALTIMEDATAINCOMPLETE" />
</property>
<property name="minmaxdelaydataincomplete" type="java.lang.Boolean">
<column name="MINMAXDELAYDATAINCOMPLETE" />
</property>
<property name="minimumdelayprojection" type="java.lang.Boolean">
<column name="MINIMUMDELAYPROJECTION" />
</property>
<property name="realtimearrivalprojection" type="java.lang.Boolean">
<column name="REALTIMEARRIVALPROJECTION" />
</property>
<property name="realtimedepartureprojection" type="java.lang.Boolean">
<column name="REALTIMEDEPARTUREPROJECTION" />
</property>
</class>
</hibernate-mapping>
以下是主要的hibernate.cfg.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-
configuration-3.0.dtd">
<hibernate-configuration>
<session-factory >
<!-- Database connection settings -->
<property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/newTestDB</property>
<property name="connection.driver_class">org.postgresql.Driver</property>
<property name="connection.username">postgres</property>
<property name="connection.password">usman123</property>
<property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>
<!-- SQL dialect - generate SQL for a particular database -->
<property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<!-- Echo all executed SQL statements -->
<property name="show_sql">false</property>
<!-- Automatic schema creation (begin) ===
<property name="hibernate.hbm2ddl.auto">create</property>
Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Mapping resource configuration files -->
<mapping resource="de/db/journeyTracker/model/TestTable.hbm.xml"/>
<mapping resource="de/db/journeyTracker/model/gpspos.hbm.xml"/>
<mapping resource="de/db/journeyTracker/model/journey.hbm.xml"/>
<mapping resource="de/db/journeyTracker/model/trip.hbm.xml"/>
</session-factory> </hibernate-configuration>
Exception in thread "main" java.lang.ClassCastException: java.lang.Integer cannot be cast to de.db.journeyTracker.model.journey
at de.db.journeyTracker.model.journey.findalljourney(journey.java:323)
我尝试了以下代码..正如你所建议的那样..但它仍然是给出异常
List<Object[]> allJourney;
allJourney = query.list();
int Count = 0;
for (Object[] Journey : allJourney)
{
String strJourneyId = ((journey) Journey[0]).getJourneyid().toString();
String strOperatingDay = ((journey) Journey[0]).getOperatingday().toString();
String strLineName = ((journey) Journey[0]).getLinename();
String strSchedualeDeparture = ((journey) Journey[0]).getScheduledeparture().toString();
String strSchedualeDepartureStopName = ((journey) Journey[0]).getScheduledeparturestopname();
System.out.println(strJourneyId + " " + strOperatingDay + " " + strLineName + " " + strSchedualeDeparture + " " + strSchedualeDepartureStopName);
}
答案 0 :(得分：2)
在Hibernate中使用HSQL查询 试试这种类型的查询
1＆gt; String qryAllJourney =“from journey j”; 这将返回所有旅程表记录，没有任何类型转换异常。
或者 - 假设类旅程具有适当的构造函数 - 作为实际的类型安全Java对象： 字符串qryAllJourney =“从旅程中选择新旅程（j.id，j.operatingday，j.linename，j.scheduledeparture，j.scheduledeparturestopname）”;
如果您想了解更多详情，请浏览此链接。
http://docs.jboss.org/hibernate/orm/3.3/reference/en/html/queryhql.html
答案 1 :(得分：1)
此查询：
SELECT j.id , j.operatingday, j.linename,
j.scheduledeparture, j.scheduledeparturestopname
FROM journey j
未选择“旅程实例列表”。而是选择List of Object数组。数组元素与选择列表中的值匹配：
[0] = j.id
[1] = j.operatingday
...
请改用以下代码：
SELECT j FROM journey j
但是如果你想坚持使用返回的数组，请转到：
List<Object[]> allJourney = query.list();
//do what ever you need to do with result:
for (Object[] row: allJourney) {
Integer id = (Integer) row[0];
Date operatingday = (Date) row[1];
}
答案 2 :(得分：0)
这应该是一个hsql查询！
String qryAllJourney = "SELECT j.id , j.operatingday, j.linename, j.scheduledeparture, j.scheduledeparturestopname FROM journey j";
它应该是这样的;
String qryAllJourney = "from Journey";