Application.java

package com.test;

import com.fasterxml.jackson.annotation.JsonRootName;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.SerializationFeature;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@ComponentScan("com.test")
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @RestController
    @RequestMapping(value="/")
    public static class MyRestController  {

        @RequestMapping(value="test", method = RequestMethod.POST,
                consumes = MediaType.APPLICATION_JSON_VALUE)
        public ResponseEntity<User> testPost(@RequestBody User user) {
            return new ResponseEntity<User>(user, HttpStatus.OK);
        }
    }

    @Configuration
    public static class JacksonConfig {

        @Bean
        public Jackson2ObjectMapperBuilder jacksonBuilder() {
            Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
            builder.featuresToEnable(DeserializationFeature.UNWRAP_ROOT_VALUE);
            return builder;
        }
    }

    @JsonRootName("user")
    public static class User {
        private String name;
        private int age;

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public int getAge() {
            return age;
        }

        public void setAge(int age) {
            this.age = age;
        }
    }
}

build.gradle

group 'spring-boost-jackson'
version '1.0-SNAPSHOT'
buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:1.3.2.RELEASE")
    }
}

apply plugin: 'java'
apply plugin: 'idea'
apply plugin: 'spring-boot'

sourceCompatibility = 1.5

repositories {
    mavenCentral()
}

dependencies {
    testCompile group: 'junit', name: 'junit', version: '4.11'
    compile("org.springframework.boot:spring-boot-starter-web")
    compile 'com.fasterxml.jackson.core:jackson-core:2.7.1'
}