Spring provides support for JSON content-type to backing object conversion by automatically using MappingJackson2HttpMessageConverter. This message converter won't get activated unless we add jackson-databind jar in the classpath.
This tutorial specifically covers Jackson 2. Note that as of Spring Framework 7.0, MappingJackson2HttpMessageConverter is deprecated in favor of Jackson 3 support, with removal planned for Spring Framework 7.2. The replacement is JacksonJsonHttpMessageConverter, which is built on Jackson 3's immutable JsonMapper API — see the follow-up tutorial.
Example
Add jackson-databind dependency
Add this dependency in maven pom.xml
pom.xml<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.21.1</version>
</dependency>
Creating Backing Object
package com.logicbig.example;
import java.io.Serializable;
public class User implements Serializable {
private Long id;
private String name;
private String password;
private String emailAddress;
.............
}
Creating Controller
package com.logicbig.example;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import java.util.List;
@Controller
@RequestMapping("users")
public class UserController {
@Autowired
private UserService userService;
@RequestMapping(value = "register", method = RequestMethod.POST,
consumes = MediaType.APPLICATION_JSON_VALUE)
@ResponseStatus(HttpStatus.CREATED)
public void handleJsonPostRequest (@RequestBody User user, Model model) {
System.out.println("saving user: "+user);
userService.saveUser(user);
}
@RequestMapping(method = RequestMethod.GET,
produces = MediaType.APPLICATION_JSON_VALUE)
@ResponseStatus(HttpStatus.OK)
@ResponseBody
public List<User> handleAllUserRequest () {
return userService.getAllUsers();
}
}
Unit Test
package com.logicbig.example;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.test.context.junit.jupiter.web.SpringJUnitWebConfig;
import org.springframework.test.web.servlet.assertj.MockMvcTester;
import org.springframework.web.context.WebApplicationContext;
import static org.assertj.core.api.Assertions.assertThat;
import static org.springframework.http.HttpStatus.CREATED;
import static org.springframework.http.HttpStatus.OK;
@SpringJUnitWebConfig(MyWebConfig.class)
public class ControllerTest {
@Autowired
private WebApplicationContext wac;
private MockMvcTester mockMvcTester;
@org.junit.jupiter.api.BeforeEach
public void setup() {
this.mockMvcTester = MockMvcTester.from(this.wac);
}
@Test
public void testUserController() {
String userInJson = createUserInJson("joe",
"joe@example.com",
"abc");
assertThat(this.mockMvcTester.post().uri("/users/register")
.contentType(MediaType.APPLICATION_JSON)
.content(userInJson)
.exchange())
.hasStatus(CREATED);
String userInJson1 = createUserInJson("mike",
"mike@example.com",
"123");
assertThat(this.mockMvcTester.post()
.uri("/users/register")
.contentType(MediaType.APPLICATION_JSON)
.content(userInJson1)
.exchange())
.hasStatus(CREATED);
var getResult = this.mockMvcTester.get().uri("/users")
.accept(MediaType.APPLICATION_JSON)
.exchange();
assertThat(getResult)
.hasStatus(OK)
.bodyJson().extractingPath("$").asArray().hasSize(2);
assertThat(getResult).bodyJson().extractingPath("$[0].id")
.isEqualTo(1);
assertThat(getResult).bodyJson().extractingPath("$[0].name")
.isEqualTo("joe");
assertThat(getResult).bodyJson().extractingPath("$[0].emailAddress")
.isEqualTo("joe@example.com");
assertThat(getResult).bodyJson().extractingPath("$[0].password")
.isEqualTo("abc");
assertThat(getResult).bodyJson().extractingPath("$[1].id")
.isEqualTo(2);
assertThat(getResult).bodyJson().extractingPath("$[1].name")
.isEqualTo("mike");
assertThat(getResult).bodyJson().extractingPath("$[1].emailAddress")
.isEqualTo("mike@example.com");
assertThat(getResult).bodyJson().extractingPath("$[1].password")
.isEqualTo("123");
}
private static String createUserInJson(String name,
String email,
String password) {
return "{ \"name\": \"" + name + "\", " +
"\"emailAddress\":\"" + email + "\"," +
"\"password\":\"" + password + "\"}";
}
}
mvn clean test -Dtest="ControllerTest" Output$ mvn clean test -Dtest="ControllerTest"
[INFO] Scanning for projects...
[WARNING]
[WARNING] Some problems were encountered while building the effective model for com.logicbig.example:spring-json-example:war:1.0-SNAPSHOT
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-war-plugin is missing. @ line 55, column 21
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING]
[INFO]
[INFO] --------------< com.logicbig.example:spring-json-example >--------------
[INFO] Building spring-json-example 1.0-SNAPSHOT
[INFO] from pom.xml
[INFO] --------------------------------[ war ]---------------------------------
[INFO]
[INFO] --- clean:3.2.0:clean (default-clean) @ spring-json-example ---
[INFO] Deleting D:\example-projects\spring-mvc\spring-json-example\target
[INFO]
[INFO] --- resources:3.3.1:resources (default-resources) @ spring-json-example ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\example-projects\spring-mvc\spring-json-example\src\main\resources
[INFO]
[INFO] --- compiler:3.5.1:compile (default-compile) @ spring-json-example ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 5 source files to D:\example-projects\spring-mvc\spring-json-example\target\classes
[INFO]
[INFO] --- resources:3.3.1:testResources (default-testResources) @ spring-json-example ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\example-projects\spring-mvc\spring-json-example\src\test\resources
[INFO]
[INFO] --- compiler:3.5.1:testCompile (default-testCompile) @ spring-json-example ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to D:\example-projects\spring-mvc\spring-json-example\target\test-classes
[INFO]
[INFO] --- surefire:3.2.5:test (default-test) @ spring-json-example ---
[INFO] Using auto detected provider org.apache.maven.surefire.junit4.JUnit4Provider
[WARNING] file.encoding cannot be set as system property, use <argLine>-Dfile.encoding=...</argLine> instead
[INFO]
[INFO] -------------------------------------------------------
[INFO] T E S T S
[INFO] -------------------------------------------------------
[INFO] Running com.logicbig.example.ControllerTest
saving user: User{id=null, name='joe', password='abc', emailAddress='joe@example.com'}
saving user: User{id=null, name='mike', password='123', emailAddress='mike@example.com'}
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.782 s -- in com.logicbig.example.ControllerTest
[INFO]
[INFO] Results:
[INFO]
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.965 s
[INFO] Finished at: 2026-07-15T12:12:19+08:00
[INFO] ------------------------------------------------------------------------
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
Example ProjectDependencies and Technologies Used: - spring-webmvc 7.0.6 (Spring Web MVC)
Version Compatibility: 3.2.9.RELEASE - 7.0.6 Version compatibilities of spring-webmvc with this example: Versions in green have been tested.
- spring-test 7.0.6 (Spring TestContext Framework)
- jakarta.servlet-api 6.1.0 (Jakarta Servlet API documentation)
- junit-jupiter-engine 6.0.3 (Module "junit-jupiter-engine" of JUnit)
- jackson-databind 2.21.1 (General data-binding functionality for Jackson: works on core streaming API)
- hamcrest 3.0 (Core API and libraries of hamcrest matcher framework)
- assertj-core 3.26.3 (Rich and fluent assertions for testing in Java)
- json-path 2.10.0 (A library to query and verify JSON)
- JDK 25
- Maven 3.9.11
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