CODEWITHSUNDEEP
javajsonspring-mvcserialization
hevi
hevi

Reputation: 2746

JSON serialize with different field names on Spring MVC

I've been working on a a controller in which I want to return json string as a response. But the problem is that, I want to change some field names during serialize/deserialize, but I don't want to use ugly annotations on my entity objects.

Lets say

@Controller
@RequestMapping("/kfc/brands")
public class JSONController {

    @RequestMapping(value="{name}", method = RequestMethod.GET)
    public @ResponseBody Shop getShopInJSON(@PathVariable String name) {

        Shop shop = new Shop();
        shop.setName(name);
        shop.setStaffNames(new String[]{"mkyong1", "mkyong2"});

        return shop;

    }

}

public class Shop {
        String name;
        String staffNames[];
        String location;

        //getter and setter methods

    }

I want the controller to return staffNames as staff_names , location as address without using any annotations.

I assume there has to be a custom object mapper structure to to that but couldn't find a proper example. I have no problems with setting field names manually in the serialization code.

PS: example taken from mkyong

Upvotes: 1

Views: 1124

Answers (1)

achabahe
achabahe

Reputation: 2565

To enable the transformation from Camel cases fields Names like firstName to underscore field name like field_name you should register a custom json2Object Conveter I suppose that you have spring 3.1 or later

  • For steps 1-1 and 1-2 you do only one of them and not both.

1. Configure you context

1-1. If you use XML Configuration then you put this code in you configuration file

    <beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
    http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd">
    <!-- the important part start from here-->
    <mvc:annotation-driven>
        <mvc:message-converters>
            <bean
                class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper" ref="objectMapper" />
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>
    <bean id="objectMapper"
        class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
        <property name="propertyNamingStrategy" >
        <util:constant static-field="com.fasterxml.jackson.databind.PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES"/>
        <property name="indentOutput" value="true"/>
        </property>
    </bean>

1-2. If you use programmatic configuartion

 @Configuration
@EnableWebMvc
public class WebConfiguration extends WebMvcConfigurerAdapter {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder()
                .indentOutput(true)
                .propertyNamingStrategy(com.fasterxml.jackson.databind.PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES);
        converters.add(new MappingJackson2HttpMessageConverter(builder.build()));
    }

}

2.Fetching dependencies

Download these jars and put them in your application jackson-annotations-2.7.2,jackson-core-2.7.2,jackson-databind-2.7.2 Here is the Maven repository

this converter will convert all REST messages with this header Content-Type=application/json

PS: this converter will not convert your json message to string since String doesn't have a default constructor , to read you JSON message as string in your controller you use Content-Type=applciation/text in your client message header

Upvotes: 1

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