如何使OpenSessionInViewInterceptor在Spring MVC中工作

问题描述

我正在尝试在Spring MVC中设置OpenSessionInViewInterceptor以修复:org.hibernate.LazyInitializationException:无法初始化代理-没有会话.

I'm trying to set up OpenSessionInViewInterceptor in spring mvc to fix: org.hibernate.LazyInitializationException: could not initialize proxy - no Session.

下面是我已经拥有的代码以及错误的来源.

Below is the code I already have and where the error comes from.

AppConfig.java

AppConfig.java

@Configuration
@PropertySource("classpath:db.properties")
@EnableTransactionManagement
@ComponentScans(value = { @ComponentScan("com.debugger.spring.web.tests"),  @ComponentScan("com.debugger.spring.web.service"), @ComponentScan("com.debugger.spring.web.dao"),
@ComponentScan("com.debugger.spring.web.controllers") })
public class AppConfig implements WebMvcConfigurer {

@Autowired
private Environment env;

@Bean
public LocalSessionFactoryBean getSessionFactory() {
    LocalSessionFactoryBean factoryBean = new LocalSessionFactoryBean();

    Properties props = new Properties();

    // Setting JDBC properties
    ...

    // Setting Hibernate properties
    ...

    // Setting C3P0 properties
        ...

    return factoryBean;
}

@Bean
public OpenSessionInViewInterceptor openSessionInViewInterceptor() {
    OpenSessionInViewInterceptor openSessionInViewInterceptor = new OpenSessionInViewInterceptor();
    openSessionInViewInterceptor.setSessionFactory(getSessionFactory().getObject());
    return openSessionInViewInterceptor;
}
}

featured.jsp

featured.jsp

<c:choose>
                            <c:when
                                test='${article.user.isSubscribed() and article.user.subscription.type eq "silver" }'>
                                <a class="bold"
                                    href='${pageContext.request.contextPath}/u/${article.user.username}'><span
                                    class="silvername"> <c:out value="${article.user.name}"></c:out></span></a>
                            </c:when>
                            <c:when
                                test='${article.user.isSubscribed() and article.user.subscription.type eq "gold" }'>
                                <a class="bold"
                                    href='${pageContext.request.contextPath}/u/${article.user.username}'><span
                                    class="goldname"> <c:out value="${article.user.name}"></c:out></span></a>
                            </c:when>
                            <c:when
                                test='${article.user.isSubscribed() and article.user.subscription.type eq "premium" }'>
                                <a class="bold"
                                    href='${pageContext.request.contextPath}/u/${article.user.username}'><span
                                    class="premiumname"> <c:out
                                            value="${article.user.name}"></c:out></span></a>
                            </c:when>
                            <c:otherwise>
                                <a class="bold"
                                    href='${pageContext.request.contextPath}/u/${article.user.username}'><span>
                                        <c:out value="${article.user.name}"></c:out>
                                </span></a>
                            </c:otherwise>
                        </c:choose>

$ {article.user.isSubscribed()}最有可能引发错误，因为无法获取用户.我希望它可以不使用急切的获取程序来运行，并且我认为可以通过正确设置OpenSessionInViewInterceptor来实现它.

${article.user.isSubscribed()} throws the error most likely because user cannot be fetched. I want it to run without using eager fetch and I think I can acheive it by setting up OpenSessionInViewInterceptor correctly.

推荐答案

覆盖 WebMvcConfigurer#addInterceptors(InterceptorRegistry)在配置类中:

@Override
public void addInterceptors(InterceptorRegistry registry) {
    OpenSessionInViewInterceptor openSessionInViewInterceptor = new OpenSessionInViewInterceptor();
    openSessionInViewInterceptor.setSessionFactory(getSessionFactory().getObject());

    registry.addWebRequestInterceptor(openSessionInViewInterceptor).addPathPatterns("/**");
}

还要在配置类上添加@EnableWebMvc.

针对OP的评论:

我不确定为什么它不起作用.对我来说，一切似乎都很好.还有另一种方法可以实现:

I am not sure why it is not working. Everything seems fine to me. There is another way you can achieve this:

设置hibernate.enable_lazy_load_no_trans属性true.

请参见 23.9 .1.有关更多信息，请参见《 Hibernate用户指南》中的获取属性" .

但这不是 指南中所述的一个很好的选择:

But this is not a very good option as stated in the guide:

In reality, you shouldn’t probably enable this setting anyway.

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