Convert JSON to java object in RESTful Web Services in Java

This example shows how to convert data from json to java object in RESTful Web Services with Java Using Jersey(JAX-RS). There are many ways for parse json string to object java in restful web services. In this java json parser example , we will use jackson dependency(maven project) if you are not use maven project then you can use jackson jar for JSON parsing.In this article we explain restful web services post method example in java  . We will send JSON data in post request and get JSON data from post request in java .

To learn how to convert json to java object in restful web service , firstly we will see example of restful web services , Now you have idea about rest api implementation in java , So in this example we will send request with json and parse it to java pojo . Firstly create a maven project as we have create in  simple restful web service example and will create handler class , configure web.xml and add dependencies in pom.xml . Now we will see implementation jax-rs post json example .

Java Restful API POST JSON Example

Step 1: Create hander class and define path , method and response. In this class we will write jax-rs post json method .

UserHander.java

package com.javaproficiency.jerseydemo.demo;
import javax.ws.rs.Consumes;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;
import com.javaproficiency.jerseydemo.model.User;

@Path("/user")
public class UserHander {

@POST
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public Response addUser(User user) {
System.out.println("user name"+user.getName());
System.out.println("user city="+user.getCity());
return Response.status(Status.OK).entity(user).build();
}

}

Step 2: In this example we need one java pojo for mapping json to java object . This java pojo have the same filed as key in json string . In our example we will use json with name and city key o string type , So we will create pojo with name and city field .

User.java

package com.javaproficiency.jerseydemo.model;

public class User {

private String name;
private String city;

public String getName() {
return name;
}

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

public String getCity() {
return city;
}

public void setCity(String city) {
this.city = city;
}

}

Step 3: configure web.xml file as

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
     http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" 
  id="WebApp_ID" version="3.0">
<display-name>JerseyDemo</display-name>
<servlet>
<servlet-name>RestServices</servlet-name>
<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>

<init-param>
<param-name>jersey.config.server.provider.packages</param-name>
<param-value>com.javaproficiency.jerseydemo.demo</param-value>
</init-param>

<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>RestServices</servlet-name>
<url-pattern>/rest/*</url-pattern>
</servlet-mapping>
</web-app>

Step 4: Add dependency in pom.xml file as bellow.

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>InstagramPost</groupId>
<artifactId>InstagramPost</artifactId>
<version>0.0.1-SNAPSHOT</version>
<build>
<sourceDirectory>src</sourceDirectory>
<plugins>
<plugin>
<groupId>com.craterzone.instagrampost</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
</plugins>
</build>

<dependencies>
<dependency>
<groupId>org.glassfish.jersey.core</groupId>
<artifactId>jersey-server</artifactId>
<version>2.13</version>
</dependency>

<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<!-- if your container implements Servlet API older
 than 3.0, use "jersey-container-servlet-core" -->
<artifactId>jersey-container-servlet</artifactId>
<version>2.13</version>
</dependency>

<dependency>
<groupId>javax.ws.rs</groupId>
<artifactId>javax.ws.rs-api</artifactId>
<version>2.0</version>
</dependency>

<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-servlet</artifactId>
<scope>provided</scope>
<version>2.16</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>

<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-json-jackson</artifactId>
<version>2.10.1</version>
</dependency>

<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
<version>1.9.2</version>
</dependency>
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-core-asl</artifactId>
<version>1.9.2</version>
</dependency>

<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-grizzly2-http</artifactId>
<version>2.16</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-grizzly2-servlet</artifactId>
<version>2.16</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-jdk-http</artifactId>
<version>2.16</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-simple-http</artifactId>
<version>2.16</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-jetty-http</artifactId>
<version>2.16</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-jetty-servlet</artifactId>
<version>2.16</version>
</dependency>

</dependencies>

</project>

Step 5:  This is  project structure of our application.

 

Step 6: Hit web service using rest console or postman

url =http://localhost:8080/JerseyDemo/rest/user

json:

{
“name”: “raja”,
“city”: “delhi”
}

 

Response:
{
“name”: “raja”,
“city”: “delhi”
}

we have seen example for convert json to pojo in java using jackson . We have seen implementation of jersey post json example in java .You have learned How to send JSON request to RESTful webservice in Java in this rest api post json example . You can learn more example of restful webservice using jersey in java .