Spring Boot Ajax example

This article will show you how to use jQuery.ajax to send a HTML form request to a Spring REST API and return a JSON response.

Tools used :

1. Spring Boot 1.5.1.RELEASE
2. Spring 4.3.6.RELEASE
3. Maven 3
4. jQuery
5. Bootstrap 3

1. Project Structure

A standard Maven project structure.

2. Project Dependency

A normal Spring Boot dependency and some webjars resources.

<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.mkyong</groupId>
    <artifactId>spring-boot-ajax-example</artifactId>
    <packaging>jar</packaging>
    <version>1.0</version>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.1.RELEASE</version>
    </parent>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.webjars</groupId>
            <artifactId>jquery</artifactId>
            <version>2.2.4</version>
        </dependency>
        <dependency>
            <groupId>org.webjars</groupId>
            <artifactId>bootstrap</artifactId>
            <version>3.3.7</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <!-- Package as an executable jar/war -->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

3. Spring REST API

3.1 A REST controller, accept a SearchCriteria and return a ResponseEntity

package com.mkyong.controller;
import com.mkyong.model.AjaxResponseBody;
import com.mkyong.model.SearchCriteria;
import com.mkyong.model.User;
import com.mkyong.services.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.validation.Errors;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import javax.validation.Valid;
import java.util.List;
import java.util.stream.Collectors;
@RestController
public class SearchController {
    UserService userService;
    @Autowired
    public void setUserService(UserService userService) {
        this.userService = userService;
    @PostMapping("/api/search")
    public ResponseEntity<?> getSearchResultViaAjax(
            @Valid @RequestBody SearchCriteria search, Errors errors) {
        AjaxResponseBody result = new AjaxResponseBody();
        //If error, just return a 400 bad request, along with the error message
        if (errors.hasErrors()) {
            result.setMsg(errors.getAllErrors()
                        .stream().map(x -> x.getDefaultMessage())
                        .collect(Collectors.joining(",")));
            return ResponseEntity.badRequest().body(result);
        List<User> users = userService.findByUserNameOrEmail(search.getUsername());
        if (users.isEmpty()) {
            result.setMsg("no user found!");
        } else {
            result.setMsg("success");
        result.setResult(users);
        return ResponseEntity.ok(result);

3.2 Some POJO.

package com.mkyong.model;
import java.util.List;
public class AjaxResponseBody {
    String msg;
    List<User> result;
    //getters and setters

package com.mkyong.model;
public class User {
    String username;
    String password;
    String email;
    public User(String username, String password, String email) {
        this.username = username;
        this.password = password;
        this.email = email;
    //getters and setters

3.3 Validation.

package com.mkyong.model;
import org.hibernate.validator.constraints.NotBlank;
public class SearchCriteria {
    @NotBlank(message = "username can't empty!")
    String username;
    public String getUsername() {
        return username;
    public void setUsername(String username) {
        this.username = username;

3.4 A service to init some users for searching.

package com.mkyong.services;
import com.mkyong.model.User;
import org.springframework.stereotype.Service;
import javax.annotation.PostConstruct;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
@Service
public class UserService {
    private List<User> users;
    // Love Java 8
    public List<User> findByUserNameOrEmail(String username) {
        List<User> result = users.stream()
            .filter(x -> x.getUsername().equalsIgnoreCase(username))
            .collect(Collectors.toList());
        return result;
    // Init some users for testing
    @PostConstruct
    private void iniDataForTesting() {
        users = new ArrayList<User>();
        User user1 = new User("mkyong", "password111", "mkyong@yahoo.com");
        User user2 = new User("yflow", "password222", "yflow@yahoo.com");
        User user3 = new User("laplap", "password333", "mkyong@yahoo.com");
        users.add(user1);
        users.add(user2);
        users.add(user3);

3.5 Spring Boot Starter.

package com.mkyong;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class SpringBootWebApplication {
    public static void main(String[] args) throws Exception {
        SpringApplication.run(SpringBootWebApplication.class, args);

4. HTML form + jQuery Ajax

4.1 A simple HTML form, decorated with bootstrap.

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <title>Spring Boot ajax example</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
    <link rel="stylesheet" type="text/css"
          href="webjars/bootstrap/3.3.7/css/bootstrap.min.css"/>
</head>
<body>
<nav class="navbar navbar-inverse">
    <div class="container">
        <div class="navbar-header">
            <a class="navbar-brand" href="#">Mkyong.com</a>
        </div>
    </div>
</nav>
<div class="container" style="min-height: 500px">
    <div class="starter-template">
        <h1>Spring Boot AJAX Example</h1>
        <div id="feedback"></div>
        <form class="form-horizontal" id="search-form">
            <div class="form-group form-group-lg">
                <label class="col-sm-2 control-label">Username</label>
                <div class="col-sm-10">
                    <input type="text" class="form-control" id="username"/>
                </div>
            </div>
            <div class="form-group">
                <div class="col-sm-offset-2 col-sm-10">
                    <button type="submit" id="bth-search"
                            class="btn btn-primary btn-lg">Search
                    </button>
                </div>
            </div>
        </form>
    </div>
</div>
<div class="container">
    <footer>
        <p>
            © <a href="http://www.mkyong.com">Mkyong.com</a> 2017
        </p>
    </footer>
</div>
<script type="text/javascript"
        src="webjars/jquery/2.2.4/jquery.min.js"></script>
<script type="text/javascript" src="js/main.js"></script>
</body>
</html>

4.2 Get HTML form, convert the search criteria into JSON format via JSON.stringify, and send POST request via jQuery.ajax

$(document).ready(function () {
    $("#search-form").submit(function (event) {
        //stop submit the form, we will post it manually.
        event.preventDefault();
        fire_ajax_submit();
    });
});
function fire_ajax_submit() {
    var search = {}
    search["username"] = $("#username").val();
    $("#btn-search").prop("disabled", true);
    $.ajax({
        type: "POST",
        contentType: "application/json",
        url: "/api/search",
        data: JSON.stringify(search),
        dataType: 'json',
        cache: false,
        timeout: 600000,
        success: function (data) {
            var json = "<h4>Ajax Response</h4><pre>"
                + JSON.stringify(data, null, 4) + "</pre>";
            $('#feedback').html(json);
            console.log("SUCCESS : ", data);
            $("#btn-search").prop("disabled", false);
        },
        error: function (e) {
            var json = "<h4>Ajax Response</h4><pre>"
                + e.responseText + "</pre>";
            $('#feedback').html(json);
            console.log("ERROR : ", e);
            $("#btn-search").prop("disabled", false);
    });

Done.

5. DEMO

5.1 Start Spring Boot

$ mvn spring-boot:run
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.5.1.RELEASE)
2017-02-03 14:56:36 DEBUG com.mkyong.SpringBootWebApplication - Running with Spring Boot v1.5.1.RELEASE, Spring v4.3.6.RELEASE
2017-02-03 14:56:36 INFO  com.mkyong.SpringBootWebApplication - No active profile set, falling back to default profiles: default
2017-02-03 14:56:39 INFO  com.mkyong.SpringBootWebApplication - Started SpringBootWebApplication in 2.828 seconds (JVM running for 3.295)

5.2 Access http://localhost:8080/

5.3 If username is empty!

5.4 If username is not found!

5.5 If username is found!

6. Download Source Code

References

1. Spring IO – Building a RESTful Web Service
2. MDN – JSON.stringify()
3. Spring 4 MVC Ajax Hello World Example