如何使 OpenSessionInViewInterceptor 在 Spring mvc 中工作

Question

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 - 无会话。

下面是我已有的代码以及错误的来源。

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

<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()} 最有可能抛出错误，因为无法获取用户。我希望它运行不使用急切获取，我想我可以通过正确设置 OpenSessionInViewInterceptor 来实现它。

Answer 1

在您的配置中覆盖 WebMvcConfigurer#addInterceptors(InterceptorRegistry) class:

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

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

同时在配置 class 上添加 @EnableWebMvc。

回应OP的评论：

我不确定为什么它不起作用。我觉得一切都很好。还有另一种方法可以实现此目的：

设置hibernate.enable_lazy_load_no_trans属性true.

有关更多信息，请参阅 23.9.1. Fetching properties in Hibernate User Guide。

但这不是指南中所述的一个很好的选择：

Although enabling this configuration can make LazyInitializationException go away, it’s better to use a fetch plan that guarantees that all properties are properly initialized before the Session is closed.
In reality, you shouldn’t probably enable this setting anyway.

如何使 OpenSessionInViewInterceptor 在 Spring mvc 中工作

How to make OpenSessionInViewInterceptor work in Spring mvc

java

hibernate

spring-mvc

interceptor