AngularJS Restful web service example using $http

This post is in continuation with AngularJS web services tutorial

In previous post, we have already seen Restful web services CRUD example. In this post, we will use AngularJS to call rest CRUD APIs. So we are going to create a view and then perform CRUD operations on the basis of button clicks.

Source code:

Here are steps to create a simple Restful web services(JAXWS)  using jersey which will provide CRUD opertion.

Maven dependencies

2) We need to add jersey jars utility in the classpath.

<dependency>
   <groupId>com.sun.jersey</groupId>
   <artifactId>jersey-servlet</artifactId>
   <version>${jersey.version}</version>
 </dependency>
 <dependency>
   <groupId>com.sun.jersey</groupId>
   <artifactId>jersey-json</artifactId>
   <version>${jersey.version}</version>
 </dependency>
 

Jersey internally uses Jackson for Json Handling, so it will be used to marshal pojo objects to JSON.

<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/maven-v4_0_0.xsd">
 <modelVersion>4.0.0</modelVersion>
 <groupId>com.arpit.java2blog</groupId>
 <artifactId>JAXRSJsonExample</artifactId>
 <packaging>war</packaging>
 <version>0.0.1-SNAPSHOT</version>
 <name>JAXRSJsonExample Maven Webapp</name>
 <url>http://maven.apache.org</url>
   <properties>
        <jersey.version>1.18.3</jersey.version>
    </properties>
 <dependencies>
  <dependency>
   <groupId>junit</groupId>
   <artifactId>junit</artifactId>
   <version>3.8.1</version>
   <scope>test</scope>
  </dependency>

  <dependency>
   <groupId>com.sun.jersey</groupId>
   <artifactId>jersey-servlet</artifactId>
   <version>${jersey.version}</version>
  </dependency>
  <dependency>
   <groupId>com.sun.jersey</groupId>
   <artifactId>jersey-json</artifactId>
   <version>${jersey.version}</version>
  </dependency>

  <dependency>
   <groupId>commons-logging</groupId>
   <artifactId>commons-logging</artifactId>
   <version>1.2</version>
  </dependency>
 </dependencies>
 <build>
  <finalName>JAXRSJsonExample</finalName>
  <plugins>
   <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.3</version>
    <configuration>
     <source>1.7</source>
     <target>1.7</target>
    </configuration>
   </plugin>
   <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-war-plugin</artifactId>
    <configuration>
     <failOnMissingWebXml>false</failOnMissingWebXml>
    </configuration>
   </plugin>
  </plugins>
 </build>

</project>

<?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"
 version="3.0">
 <display-name>Archetype Created Web Application</display-name>
 <servlet>
  <servlet-name>jersey-serlvet</servlet-name>
  <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
  <init-param>
   <param-name>com.sun.jersey.config.property.packages</param-name>
   <param-value>org.arpit.java2blog.controller</param-value>
  </init-param>
  <init-param>
   <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
   <param-value>true</param-value>
  </init-param>

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

Please change initParam “com.sun.jersey.config.property.package” property to provide correct controller package name if you are not using same package.

package org.arpit.java2blog.bean;

public class Country{

    int id;
    String countryName;
    long population;

    public Country() {
        super();
    }
    public Country(int i, String countryName,long population) {
        super();
        this.id = i;
        this.countryName = countryName;
        this.population=population;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getCountryName() {
        return countryName;
    }
    public void setCountryName(String countryName) {
        this.countryName = countryName;
    }
    public long getPopulation() {
        return population;
    }
    public void setPopulation(long population) {
        this.population = population;
    }

}

package org.arpit.java2blog.controller;

import java.util.List;

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

import org.arpit.java2blog.bean.Country;
import org.arpit.java2blog.service.CountryService;

@Path("/countries")
public class CountryController {

    CountryService countryService=new CountryService();

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public List getCountries()
    {

        List listOfCountries=countryService.getAllCountries();
        return listOfCountries;
    }

    @GET
    @Path("/{id}")
    @Produces(MediaType.APPLICATION_JSON)
    public Country getCountryById(@PathParam("id") int id)
    {
        return countryService.getCountry(id);
    }

    @POST
    @Produces(MediaType.APPLICATION_JSON)
    public Country addCountry(Country country)
    {
        return countryService.addCountry(country);
    }

    @PUT
    @Produces(MediaType.APPLICATION_JSON)
    public Country updateCountry(Country country)
    {
        return countryService.updateCountry(country);

    }

    @DELETE
    @Path("/{id}")
    @Produces(MediaType.APPLICATION_JSON)
    public void deleteCountry(@PathParam("id") int id)
    {
        countryService.deleteCountry(id);

    }

}

6) Create a class CountryService.java in package org.arpit.java2blog.service
It is just a helper class which should be replaced by database implementation. It is not very well written class, it is just used for demonstration.

package org.arpit.java2blog.service;

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

import org.arpit.java2blog.bean.Country;
import org.arpit.java2blog.exception.CountryNotFoundException;

/*
 * It is just a helper class which should be replaced by database implementation.
 * It is not very well written class, it is just used for demonstration.
 */
public class CountryService {

    static HashMap<Integer,Country> countryIdMap=getCountryIdMap();

    public CountryService() {
        super();

        if(countryIdMap==null)
        {
            countryIdMap=new HashMap<Integer,Country>();
            // Creating some object of countries while initializing
            Country indiaCountry=new Country(1, "India",10000);
            Country chinaCountry=new Country(4, "China",20000);
            Country nepalCountry=new Country(3, "Nepal",8000);
            Country bhutanCountry=new Country(2, "Bhutan",7000);

            countryIdMap.put(1,indiaCountry);
            countryIdMap.put(4,chinaCountry);
            countryIdMap.put(3,nepalCountry);
            countryIdMap.put(2,bhutanCountry);
        }
    }

    public List getAllCountries()
    {
        List countries = new ArrayList(countryIdMap.values());
        return countries;
    }

    public Country getCountry(int id)
    {
        Country country= countryIdMap.get(id);

        if(country == null)
        {
            throw new CountryNotFoundException("Country with id "+id+" not found");
        }
        return country;
    }
    public Country addCountry(Country country)
    {
        country.setId(getMaxId()+1);
        countryIdMap.put(country.getId(), country);
        return country;
    }

    public Country updateCountry(Country country)
    {
        if(country.getId()<=0)
            return null;
        countryIdMap.put(country.getId(), country);
        return country;

    }
    public void deleteCountry(int id)
    {
        countryIdMap.remove(id);
    }

    public static HashMap<Integer, Country> getCountryIdMap() {
        return countryIdMap;
    }

    // Utility method to get max id
    public static int getMaxId()
    {   int max=0;
    for (int id:countryIdMap.keySet()) {
        if(max<=id)
            max=id;

    }

    return max;
    }
}

AngularJS view

7) create angularJSCrudExample.html in WebContent folder with following content:

<html>
  <head>

  <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.4.4/angular.js"></script>

    <title>AngularJS $http Rest example</title>
 <script type="text/javascript">
            var app = angular.module("CountryManagement", []);

            //Controller Part
            app.controller("CountryController", function($scope, $http) {

                $scope.countries = [];
                $scope.countryForm = {
                    id : -1,
                    countryName : "",
                    population : ""
                };

                //Now load the data from server
                _refreshCountryData();

                //HTTP POST/PUT methods for add/edit country
                // with the help of id, we are going to find out whether it is put or post operation

                $scope.submitCountry = function() {

                    var method = "";
                    var url = "";
                    if ($scope.countryForm.id == -1) {
                        //Id is absent in form data, it is create new country operation
                        method = "POST";
                        url = 'rest/countries';
                    } else {
                        //Id is present in form data, it is edit country operation
                        method = "PUT";
                        url = 'rest/countries';
                    }

                    $http({
                        method : method,
                        url : url,
                        data : angular.toJson($scope.countryForm),
                        headers : {
                            'Content-Type' : 'application/json'
                        }
                    }).then( _success, _error );
                };

                //HTTP DELETE- delete country by Id
                $scope.deleteCountry = function(country) {
                    $http({
                        method : 'DELETE',
                        url : 'rest/countries/' + country.id
                    }).then(_success, _error);
                };

             // In case of edit, populate form fields and assign form.id with country id
                $scope.editCountry = function(country) {

                    $scope.countryForm.countryName = country.countryName;
                    $scope.countryForm.population = country.population;
                    $scope.countryForm.id = country.id;
                };

                /* Private Methods */
                //HTTP GET- get all countries collection
                function _refreshCountryData() {
                    $http({
                        method : 'GET',
                        url : 'http://localhost:8080/AngularjsJAXRSCRUDExample/rest/countries'
                    }).then(function successCallback(response) {
                        $scope.countries = response.data;
                    }, function errorCallback(response) {
                        console.log(response.statusText);
                    });
                }

                function _success(response) {
                    _refreshCountryData();
                    _clearFormData()
                }

                function _error(response) {
                    console.log(response.statusText);
                }

                //Clear the form
                function _clearFormData() {
                    $scope.countryForm.id = -1;
                    $scope.countryForm.countryName = "";
                    $scope.countryForm.population = "";

                };
            });
        </script>
        <style>

       .blue-button{
     background: #25A6E1;
     filter: progid: DXImageTransform.Microsoft.gradient( startColorstr='#25A6E1',endColorstr='#188BC0',GradientType=0);
     padding:3px 5px;
     color:#fff;
     font-family:'Helvetica Neue',sans-serif;
     font-size:12px;
     border-radius:2px;
     -moz-border-radius:2px;
     -webkit-border-radius:4px;
     border:1px solid #1A87B9
           }

       .red-button{
    background: #CD5C5C;

    padding:3px 5px;
    color:#fff;
    font-family:'Helvetica Neue',sans-serif;
    font-size:12px;
    border-radius:2px;
    -moz-border-radius:2px;
    -webkit-border-radius:4px;
    border:1px solid #CD5C5C
           }

       table {
           font-family: "Helvetica Neue", Helvetica, sans-serif;
           width: 50%;
       }

       caption {
           text-align: left;
           color: silver;
           font-weight: bold;
           text-transform: uppercase;
           padding: 5px;
       }

       th {
           background: SteelBlue;
           color: white;
       }

       tbody tr:nth-child(even) {
           background: WhiteSmoke;
       }

       tbody tr td:nth-child(2) {
           text-align:center;
       }

       tbody tr td:nth-child(3),
       tbody tr td:nth-child(4) {
           text-align: center;
           font-family: monospace;
       }

       tfoot {
           background: SeaGreen;
           color: white;
           text-align: right;
       }

       tfoot tr th:last-child {
           font-family: monospace;
       }

       td,th{
            border: 1px solid gray;
            width: 25%;
            text-align: left;
            padding: 5px 10px;
        }

        </style>
    <head>
    <body ng-app="CountryManagement" ng-controller="CountryController">
         <h1>
           AngularJS Restful web services example using $http
        </h1>
        <form ng-submit="submitCountry()">
            <table>

                <tr>
                    <th colspan="2">Add/Edit country</th>
                 </tr>
                <tr>
                    <td>Country</td>
                    <td><input type="text" ng-model="countryForm.countryName" /></td>
                </tr>
                <tr>
                    <td>Population</td>
                    <td><input type="text" ng-model="countryForm.population"  /></td>
                </tr>
                <tr>
                    <td colspan="2"><input type="submit" value="Submit" class="blue-button" /></td>
                </tr>
            </table>
        </form>
        <table>
            <tr>

                <th>CountryName</th>
                <th>Population</th>
                <th>Operations</th>

            </tr>

            <tr ng-repeat="country in countries">

    <td> {{ country.countryName }}</td>
    <td >{{ country.population }}</td>

                <td><a ng-click="editCountry(country)" class="blue-button">Edit</a> | <a ng-click="deleteCountry(country)" class="red-button">Delete</a></td>
            </tr>

        </table>

  </body>
</html>

Explanation :

• • We have injected $http as we have done in ajax example through controller constructor.

app.controller("CountryController", function($scope, $http) {

                $scope.countries = [];
...

• • We have defined various methods depending on operations such as editCountry, deleteCountry, submitCountry
  • When you click on submit button on form, it actually calls POST or PUT depending on operation. If you click on edit and submit data then it will be put operation as it will be update on existing resource. If you directly submit data, then it will be POST operation to create new resource,
  • Every time you submit data, it calls refereshCountryData() to refresh country table below.
  • When you call $http, you need to pass method type and URL, it will call it according, You can either put absolute URL or relative URL with respect to context root of web application.

 //HTTP GET- get all countries collection
                function _refreshCountryData() {
                    $http({
                        method : 'GET',
                        url : 'http://localhost:8080/JAXRSJsonCRUDExample/rest/countries'
                    }).then(function successCallback(response) {
                        $scope.countries = response.data;
                    }, function errorCallback(response) {
                        console.log(response.statusText);
                    });
                }

Right click on project -> Run as -> Maven build

9) Provide goals as clean install (given below) and click on run