Question

我在适当的结果criteria.uniqueResult（）对象引用后得到了异常。目的查询 - 从表格中获取随机结果＆＃39;引号＆＃39;来自DB Oracle

org.hibernate.exception.SQLGrammarException：无法提取ResultSet 在org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert（SQLExceptionTypeDelegate.java:80）在org.hibernate.exception.internal.StandardSQLExceptionConverter.convert（StandardSQLExceptionConverter.java:49）在org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert（SqlExceptionHelper.java:126）在org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert（SqlExceptionHelper.java:112） at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract（ResultSetReturnImpl.java:91）在org.hibernate.loader.Loader.getResultSet（Loader.java:2065）在org.hibernate.loader.Loader.executeQueryStatement（Loader.java:1862）在org.hibernate.loader.Loader.executeQueryStatement（Loader.java:1838）在org.hibernate.loader.Loader.doQuery（Loader.java:909）在org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections（Loader.java:354）在org.hibernate.loader.Loader.doList（Loader.java:2553）在org.hibernate.loader.Loader.doList（Loader.java:2539）在org.hibernate.loader.Loader.listIgnoreQueryCache（Loader.java:2369）在org.hibernate.loader.Loader.list（Loader.java:2364）在org.hibernate.loader.criteria.CriteriaLoader.list（CriteriaLoader.java:126）在org.hibernate.internal.SessionImpl.list（SessionImpl.java:1682）在org.hibernate.internal.CriteriaImpl.list（CriteriaImpl.java:380）在org.hibernate.internal.CriteriaImpl.uniqueResult（CriteriaImpl.java:402） at ua.com.goit.gojava7.kikstarter.dao.database.QuoteDaoDbImpl.getRandomQuote（QuoteDaoDbImpl.java:42） at sun.reflect.NativeMethodAccessorImpl.invoke0（Native Method） at sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:57） at sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）在java.lang.reflect.Method.invoke（Method.java:601）在org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection（AopUtils.java:302）在org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint（ReflectiveMethodInvocation.java:190）在org.springframework.aop.framework.ReflectiveMethodInvocation.proceed（ReflectiveMethodInvocation.java:157） at org.springframework.transaction.interceptor.TransactionInterceptor $ 1.proceedWithInvocation（TransactionInterceptor.java:99） at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction（TransactionAspectSupport.java:281） at org.springframework.transaction.interceptor.TransactionInterceptor.invoke（TransactionInterceptor.java:96）在org.springframework.aop.framework.ReflectiveMethodInvocation.proceed（ReflectiveMethodInvocation.java:179）在org.springframework.aop.framework.JdkDynamicAopProxy.invoke（JdkDynamicAopProxy.java:207）在com.sun.proxy。$ Proxy48.getRandomQuote（未知来源）在ua.com.goit.gojava7.kikstarter.controller.servlet.SelectoinCategories.doGet（SelectoinCategories.java:43）在javax.servlet.http.HttpServlet.service（HttpServlet.java:621）在javax.servlet.http.HttpServlet.service（HttpServlet.java:728）在org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:305）在org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:210）在org.apache.catalina.core.StandardWrapperValve.invoke（StandardWrapperValve.java:222）在org.apache.catalina.core.StandardContextValve.invoke（StandardContextValve.java:123）在org.apache.catalina.authenticator.AuthenticatorBase.invoke（AuthenticatorBase.java:502） at org.apache.catalina.core.StandardHostValve.invoke（StandardHostValve.java:171）在org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:99）在org.apache.catalina.valves.AccessLogValve.invoke（AccessLogValve.java:953）在org.apache.catalina.core.StandardEngineValve.invoke（StandardEngineValve.java:118）在org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:408）在org.apache.coyote.http11.AbstractHttp11Processor.process（AbstractHttp11Processor.java:1023） at org.apache.coyote.AbstractProtocol $ AbstractConnectionHandler.process（AbstractProtocol.java:589） at org.apache.tomcat.util.net.JIoEndpoint $ SocketProcessor.run（JIoEndpoint.java:312）在java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1145） at java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:615）在java.lang.Thread.run（Thread.java:722）

类QuoteDaoDbImpl

@Repository
public class QuoteDaoDbImpl implements QuoteDao {

    private static final String SELECT_RANDOM_QUOTE = "SELECT * FROM (SELECT * FROM quotes ORDER BY DBMS_RANDOM.VALUE) WHERE rownum = 1";

    @Autowired
    private SessionFactory sessionFactory;

    @Transactional
    @Override
    public Quote getRandomQuote() {
        Session session = sessionFactory.getCurrentSession();

        Criteria criteria = session.createCriteria(Quote.class);
        criteria.add(Restrictions.sqlRestriction(SELECT_RANDOM_QUOTE));
        criteria.setMaxResults(1);

        Quote quote = (Quote) criteria.uniqueResult();
        session.close();

        return quote;
    }
}

类SelectoinCategories

@WebServlet("/categories")
public class SelectoinCategories extends HttpServlet {

   /**
    * 
    */
    private static final long serialVersionUID = 1L;

    @Autowired
    private QuoteDao quoteDao;

    @Autowired
    private CategoryDao categoryDao;

    public void init() throws ServletException {

        SpringBeanAutowiringSupport.processInjectionBasedOnServletContext(this, getServletContext());

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {

        Quote quote = quoteDao.getRandomQuote();
        List<Category> categories = categoryDao.getAll();

        request.setAttribute("content", quote.getContent());
        request.setAttribute("author", quote.getAuthor());
        request.setAttribute("categories", categories);
        request.getRequestDispatcher("WEB-INF/jsp/categories.jsp").forward(request, response);

    }
}

课程报价

@Entity
@Table(name = "qoutes")
public class Quote {

    @Id
    @SequenceGenerator(name = "SEQ_GEN", sequenceName = "seq_id", allocationSize = 10)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SEQ_GEN")
    private int id;

    @Column(name = "content")
    private String content;

    @Column(name = "author")
    private String author;

    public Quote() {
    }

    public Quote(String content, String author) {
        this.content = content;
        this.author = author;
    }

    public int getId() {
        return id;
    }

    public String getContent() {
        return content;
    }

    public String getAuthor() {
        return author;
    }

    public void setId(int id) {
        this.id = id;
    }

    public void setContent(String quoteContent) {
        this.content = quoteContent;
    }

    public void setAuthor(String quoteAuthor) {
        this.author = quoteAuthor;
    }

    public String toString() {
        return "ID: " + id + "; Content: " + content + "; Author: " + author;
    }

}

表格报价

CREATE TABLE quotes
(
id INTEGER NOT NULL,
content VARCHAR2(500) NOT NULL,
author VARCHAR2(100) NOT NULL
);

Answer 1

修改尝试

 private static final String SELECT_RANDOM_QUOTE = 
    "SELECT id, content, author FROM 
    (SELECT * FROM quotes ORDER BY DBMS_RANDOM.VALUE) as quotes  WHERE rownum = 1";

无法在Hibernate Criteria

1 个答案: