Wednesday 26 August 2015

Jersey Implementing POST request

In previous posts, I explained how to get employee details as json response. In this post I am going to explain how to add new employee.

Input: New employee details in json format.
Output: Return new employee details with new employee id.

We need a rest client to send post data to our application. I am going to use “Advanced REST client” provided by google chrome. It is a plugin to chrome browser, you can install it easily. If you want you can use any other rest client.
@POST
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public Employee addEmployee(Employee emp) {
 return EmployeeService.addEmployee(emp);
}

addEmployee method takes json data as input and assign it to method parameter emp. Conversion of json data is done by Consumes annotation.

Following is the step-by-step procedure to send new employee details as post request.

Step 1: Create package “com.jersey_tutorial.model” to store all model classes.

Step 2:  Create model classes Employee, Address.

Address.java
package com.jersey_tutorial.model;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Address {
 private String street;
 private String city;
 private String state;
 private String country;

 public Address() {
  this("No Data", "No Data", "No Data", "No Data");
 }

 public Address(String area, String city, String state, String country) {
  super();
  this.street = area;
  this.city = city;
  this.state = state;
  this.country = country;
 }

 public String getArea() {
  return street;
 }

 public String getCity() {
  return city;
 }

 public String getCountry() {
  return country;
 }

 public String getState() {
  return state;
 }

 public void setArea(String area) {
  this.street = area;
 }

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

 public void setCountry(String country) {
  this.country = country;
 }

 public void setState(String state) {
  this.state = state;
 }

}


Employee.java
package com.jersey_tutorial.model;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Employee {
 private String firstName;
 private String lastName;
 private long id;
 private Address permAddrees;
 private Address tempAddrees;

 public Employee() {
  this("No Data", "No Data", -1, new Address(), new Address());
 }

 public Employee(String firstName, String lastName, long id,
   Address permAddrees, Address tempAddrees) {
  super();
  this.firstName = firstName;
  this.lastName = lastName;
  this.id = id;
  this.permAddrees = permAddrees;
  this.tempAddrees = tempAddrees;
 }

 public String getFirstName() {
  return firstName;
 }

 public void setFirstName(String firstName) {
  this.firstName = firstName;
 }

 public String getLastName() {
  return lastName;
 }

 public void setLastName(String lastName) {
  this.lastName = lastName;
 }

 public long getId() {
  return id;
 }

 public void setId(long id) {
  this.id = id;
 }

 public Address getPermAddrees() {
  return permAddrees;
 }

 public void setPermAddrees(Address permAddrees) {
  this.permAddrees = permAddrees;
 }

 public Address getTempAddrees() {
  return tempAddrees;
 }

 public void setTempAddrees(Address tempAddrees) {
  this.tempAddrees = tempAddrees;
 }

}

XmlRootElement annotation is used to map a Java class to an XML element.

Step 3: Create a package com.jersey_tutorial.services

Step 4: Create EmployeeService class to get all Employee details.

EmployeeService.java
package com.jersey_tutorial.services;

import java.util.HashMap;
import java.util.Map;

import com.jersey_tutorial.model.Address;
import com.jersey_tutorial.model.Employee;

public class EmployeeService {
 private static Map<Long, Employee> employees = new HashMap<>();

 static {
  initializeEmployees();
 }

 private static void initializeEmployees() {
  Address tempAddr1 = new Address("Electronic City", "Bangalore",
    "Karnataka", "India");
  Address tempAddr2 = new Address("BTM Layout", "Bangalore", "Karnataka",
    "India");
  Address permAddr1 = new Address("Marthali", "Bangalore", "Karnataka",
    "India");
  Address permAddr2 = new Address("Bharath Nagar", "Hyderabad",
    "Andhra Pradesh", "India");

  Employee emp1 = new Employee("Hari Krishna", "Gurram", 1, permAddr1,
    tempAddr1);
  Employee emp2 = new Employee("PTR", "PTR", 2, permAddr2, tempAddr2);

  employees.put(1l, emp1);
  employees.put(2l, emp2);
 }

 public static Map<Long, Employee> getAllEmployees() {
  return employees;
 }

 public static Employee getEmployee(long id) {
  return employees.get(id);
 }

 public static Employee addEmployee(Employee emp) {
  long newId = employees.size() + 1;
  emp.setId(newId);
  employees.put(newId, emp);
  return emp;
 }
}


Step 5: Create EmployeeResource.
package com.jersey_tutorial.resources;

import java.util.ArrayList;
import java.util.List;

import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

import com.jersey_tutorial.model.Employee;
import com.jersey_tutorial.services.EmployeeService;

@Path("employees")
public class EmployeeResource {

 @GET
 @Produces(MediaType.APPLICATION_JSON)
 public List<Employee> getAllEmployees() {
  return new ArrayList<>(EmployeeService.getAllEmployees().values());
 }

 @GET
 @Path("/{employeeId}")
 @Produces(MediaType.APPLICATION_JSON)
 public Employee getEmployee(@PathParam("employeeId") long empId) {
  return EmployeeService.getEmployee(empId);
 }

 @POST
 @Produces(MediaType.APPLICATION_JSON)
 @Consumes(MediaType.APPLICATION_JSON)
 public Employee addEmployee(Employee emp) {
  return EmployeeService.addEmployee(emp);
 }

}

Following is the web.xml file.

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"
 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>jersey_tutorial</display-name>
 <welcome-file-list>
  <welcome-file>index.html</welcome-file>
  <welcome-file>index.htm</welcome-file>
  <welcome-file>index.jsp</welcome-file>
  <welcome-file>default.html</welcome-file>
  <welcome-file>default.htm</welcome-file>
  <welcome-file>default.jsp</welcome-file>
 </welcome-file-list>

 <servlet>
  <servlet-name>Jersey REST Service</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.jersey_tutorial.resources</param-value>
  </init-param>
  <load-on-startup>1</load-on-startup>
 </servlet>
 <servlet-mapping>
  <servlet-name>Jersey REST Service</servlet-name>
  <url-pattern>/*</url-pattern>
 </servlet-mapping>
</web-app>


Following are the dependencies I used.
<dependencies>
 <dependency>
  <groupId>org.glassfish.jersey.containers</groupId>
  <artifactId>jersey-container-servlet-core</artifactId>
  <version>2.21</version>
 </dependency>

 <dependency>
  <groupId>org.glassfish.jersey.core</groupId>
  <artifactId>jersey-server</artifactId>
  <version>2.21</version>
 </dependency>

 <dependency>
  <groupId>org.glassfish.jersey.media</groupId>
  <artifactId>jersey-media-moxy</artifactId>
  <version>2.21</version>
 </dependency>

</dependencies>


Following is the project structure in eclipse.

Run the application on server. Open Rest client.

Select Raw button while setting headers and post data. Since we are sending json data, we need to set content type to json.

Following statement is used to set content type to application/json.
Content-Type: application/json

Following is the post body, I am going to send.

{
    "firstName": "Rama Krishna",
    "lastName": "Gurram",
    "permAddrees": {
        "area": "HSR Layout",
        "city": "Bangalore",
        "country": "India",
        "state": "Karnataka"
    },
    "tempAddrees": {
        "area": "auto nagae",
        "city": "Nellore",
        "country": "India",
        "state": "Andhra Pradesh"
    }
}

Observe above input, I am not sending id field to employee, program creates id for new employee.

Following image highlight the sections for your understanding.
After setting request headers, post body click on the send button. Once you submit the data to application, you will get newly added employee details with unique id assigned to it.




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