Spring Rest - Exception Producing Json Data [duplicate]

Answer 1

According to masterSlave provided link and solution, i adopt it to Spring Boot. i face the problem at my Spring Boot project and solve it to create HibernateAwareObjectMapper and define a custom new MappingJackson2HttpMessageConverter like below.

First add dependecy for hibernate4 to pom.xml

<dependency>
            <groupId>com.fasterxml.jackson.datatype</groupId>
            <artifactId>jackson-datatype-hibernate4</artifactId>
            <version>2.5.3</version>
        </dependency>

Create HibernateAwareObjectMapper class

/**
 * https://github.com/FasterXML/jackson-datatype-hibernate
 *
 */
public class HibernateAwareObjectMapper extends ObjectMapper {

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

    public HibernateAwareObjectMapper() {
        registerModule(new Hibernate4Module());
    }
}

Add custom MappingJackson2HttpMessageConverter class to Application.java

@Bean
    public MappingJackson2HttpMessageConverter customJackson2HttpMessageConverter() {
        MappingJackson2HttpMessageConverter jsonConverter = new MappingJackson2HttpMessageConverter();
        HibernateAwareObjectMapper hibernateAwareObjectMapper = new HibernateAwareObjectMapper();
        jsonConverter.setObjectMapper(hibernateAwareObjectMapper);
        return jsonConverter;
    }

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(customJackson2HttpMessageConverter());
        super.addDefaultHttpMessageConverters(converters);
    }

Answer 2

In addition to the solution you've already found, you can consider two more solutions. One registering the Hibernate4Module with the ObjectMapper, which will register HibernateProxySerializer, already equipped with the intelligence to deal with proxies, you can check the code not difficult to understand. Registering is also quite straight forward, form their docs:

public class HibernateAwareObjectMapper extends ObjectMapper {

    public HibernateAwareObjectMapper() {
        registerModule(new Hibernate4Module());
    }
}

than register

 <mvc:annotation-driven>
        <mvc:message-converters>
            <!-- Use the HibernateAware mapper instead of the default -->
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="path.to.your.HibernateAwareObjectMapper" />
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

Another solution is to use a DTO object, adds some boiler plate code when copying values from an entity, but gives you more control and decouples the representation from the an actual entity

Answer 3

Thanks to Evgeni for providing a link which contained the answer Annotating my CompanyVO bean with the following annotation removed the error @JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})