Hibernate 没有在类上映射新属性

Question

我正在关注一些关于 Hibernate 的教程，并且在某个时候我需要向名为 Produto 的类添加一个新属性。应该没问题，因为我之前做过并且没有问题，但问题是当我重新启动服务器时，框架似乎缺少添加的字段并且没有将其添加到数据库表中，因此我当我尝试在我的 JSP 上使用该属性时出现错误。

类：

@Entity
public class Produto {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    @NotEmpty
    private String nome;
    @NotEmpty
    private String linkDaFoto;

    @NotEmpty
    @Column(columnDefinition="TEXT")
    private String descricao;

    @Min(20)
    private double preco;

    @ManyToMany
    private List<Categoria> categorias = new ArrayList<>();

    @Version
    private int versao;

    public int getVersao() {
        return versao;
    }

    public void setVersao(int versao) {
        this.versao = versao;
    }

    public List<Categoria> getCategorias() {
        return categorias;
    }

    public void setCategorias(List<Categoria> categorias) {
        this.categorias = categorias;
    }

    @Valid
    @ManyToOne
    private Loja loja;


    public String getDescricao() {
        return descricao;
    }

    public void setDescricao(String descricao) {
        this.descricao = descricao;
    }

    //método auxiliar para associar categorias com o produto
    //se funcionar apos ter definido o relacionamento entre produto e categoria
    public void adicionarCategorias(Categoria... categorias) {
        for (Categoria categoria : categorias) {
            this.categorias.add(categoria);
        }
    }

    public String getLinkDaFoto() {
        return linkDaFoto;
    }

    public double getPreco() {
        return preco;
    }

    public void setPreco(double preco) {
        this.preco = preco;
    }

    public void setLinkDaFoto(String linkDaFoto) {
        this.linkDaFoto = linkDaFoto;
    }

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

    public Integer getId() {
        return id;
    }

    public String getNome() {
        return nome;
    }

    public void setNome(String nome) {
        this.nome = nome;
    }

    public void setLoja(Loja loja) {
        this.loja = loja;
    }

    public Loja getLoja() {
        return loja;
    }

}

错误：

org.apache.jasper.JasperException: javax.el.PropertyNotFoundException: Property [versao] not found on type [br.com.caelum.model.Produto]
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:638)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:514)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:168)
    org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303)
    org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1244)
    org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1027)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:971)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
Root Cause

javax.el.PropertyNotFoundException: Property [versao] not found on type [br.com.caelum.model.Produto]
    javax.el.BeanELResolver$BeanProperties.get(BeanELResolver.java:260)
    javax.el.BeanELResolver$BeanProperties.access$300(BeanELResolver.java:212)
    javax.el.BeanELResolver.property(BeanELResolver.java:347)
    javax.el.BeanELResolver.getValue(BeanELResolver.java:92)
    org.apache.jasper.el.JasperELResolver.getValue(JasperELResolver.java:113)
    org.apache.el.parser.AstValue.getValue(AstValue.java:169)
    org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:190)
    org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:702)
    org.apache.jsp.WEB_002dINF.views.produto.form_jsp._jspService(form_jsp.java:379)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:168)
    org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303)
    org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1244)
    org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1027)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:971)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

Answer 1

将hibernate.hbm2ddl.auto=update 添加到您的属性文件并重新启动应用程序。 Hibernate 应该会自动为您创建列。

Answer 2

我认为您必须从加载的数据中清除服务器。几周前我遇到了同样的问题，当我清理资源时，问题就解决了。