1

这是我的 hbm 文件

<hibernate-mapping>
    <class name="com.quiz.online.Quiz" table="quiz" catalog="test">
        <id name="questionid" type="long">
            <column name="questionid" />
            <generator class="identity" />
        </id>
         ...

我已经设置了身份生成器，但是当我使用此代码将值插入数据库时

public String insertQuestion(String question,String answer1,String answer2,String answer3,String answer4,String correctanswer,String reason)
    {
        JSONObject obj=new JSONObject();
        try {
            Quiz quiz=new Quiz();
            quiz.setQuestion(question);
            quiz.setAnswer1(answer1);
            quiz.setAnswer2(answer2);
            quiz.setAnswer3(answer3);
            quiz.setAnswer4(answer4);
            quiz.setCorrectanswer(correctanswer);
            quiz.setReason(reason);

            QuizDAO dao=new QuizDAO();
            Transaction tx= dao.getSession().beginTransaction();
            dao.save(quiz);
            tx.commit();

            obj.put("status", "success");
        } catch (Exception e) {
            try {
                e.printStackTrace();
            JSONObject objexp=new JSONObject();
            objexp.put("status", "failure");
            return objexp.toString();
            } catch (Exception e2) {
                e.printStackTrace();
            }
        }
        return obj.toString();
    }

它失败了，因为questionidis null。

所以它给出了以下异常。

org.hibernate.exception.GenericJDBCException: could not insert: [com.quiz.online.Quiz]
    at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:126)
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:114)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:64)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2176)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2656)
    at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71)
    at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
    at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:321)
    at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:204)
    at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:130)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210)
    at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:56)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195)
    at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:50)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93)
    at org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:563)
    at org.hibernate.impl.SessionImpl.save(SessionImpl.java:551)
    at org.hibernate.impl.SessionImpl.save(SessionImpl.java:547)
    at com.quiz.online.QuizDAO.save(QuizDAO.java:36)
    at com.quiz.services.DbUtil.insertQuestion(DbUtil.java:28)
    at com.quiz.services.Questions.insertQuestions(Questions.java:19)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.sun.jersey.server.impl.model.method.dispatch.EntityParamDispatchProvider$TypeOutInvoker._dispatch(EntityParamDispatchProvider.java:138)
    at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:67)
    at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:154)
    at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:111)
    at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:71)
    at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:111)
    at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:63)
    at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:543)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:502)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:493)
    at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:308)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:314)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.sql.SQLException: Field 'questionid' doesn't have a default value
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1078)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4120)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4052)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2503)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2664)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2815)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2458)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2375)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2359)
    at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:94)
    at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57

当我在数据库中设置自动增量时，它正在工作。所以为了发电机工作，identity我需要设置autoincrementMySQL

4

2 回答 2

0

您是否尝试过按照以下手册中的讨论进行generator class="identity"更改：http: //docs.jboss.org/hibernate/core/3.3/reference/en/html/mapping.html#mapping-generatedgenerator class="increment"

于 2013-04-24T07:22:56.547 回答
0

我很确定 MySQL 不支持身份。或者，更好地说，身份在 MySQL 中称为自动增量。正如此处引用的http://lists.mysql.com/mysql/6442，您应该使用自动增量。

于 2013-04-24T07:25:23.047 回答