Spring Mvc Jquery Ajax Json Example | Spring Mvc: Ajax & Jquery

Example of Spring MVC Ajax JSON Response

In this section, we will go through an example of a Spring MVC Ajax JSON response. We will cover the environment setup, coding the application, and running and testing the application.

Setting Up the Environment

To set up the environment for this example, we need to have the following software installed:

• Java Development Kit (JDK)
• Eclipse IDE
• Apache Tomcat Server
• jQuery library

Once we have installed these software, we can proceed to the next step.

Coding the Application

In this step, we will create a simple Spring MVC application that will handle an Ajax request and return a JSON response.

1. Create a new Spring MVC project in Eclipse IDE.
2. In the
   
web.xml

   file, add the following configuration:




dispatcher


org.springframework.web.servlet.DispatcherServlet

contextConfigLocation /WEB-INF/dispatcher-servlet.xml



dispatcher




1. Create a
   
dispatcher-servlet.xml

   file in the
   
WEB-INF

   directory and add the following configuration:

1. Create a new controller class named
   
AjaxController

   in the
   
com.example.controller

   package and add the following code:


@Controller public class AjaxController { @RequestMapping(value = "/ajax", method = RequestMethod.POST) public @ResponseBody Map

handleAjaxRequest() { Map

response = new HashMap

(); response.put("name", "John Doe"); response.put("age", 30); return response; } }





1. Create a new JSP file named
   
index.jsp

   in the
   
WEB-INF/views

   directory and add the following code:




Spring MVC Ajax JSON Response Example

Name:

Age:





Running and Testing the Application

To run and test the application, follow these steps:

1. Deploy the application on the Apache Tomcat server.
2. Open a web browser and navigate to
   
http://localhost:8080/spring-mvc-ajax-json-example/

   .
3. The page should display the name and age retrieved from the Ajax request.

That’s it! You have successfully created a Spring MVC Ajax JSON response example.

Quick Reference

1.1 In HTML, use jQuery

$.ajax()

to send a form request.


jQuery(document).ready(function($) { $("#search-form").submit(function(event) { // Prevent the form from submitting via the browser. event.preventDefault(); searchViaAjax(); }); }); function searchAjax() { var data = {} data["query"] = $("#query").val(); $.ajax({ type : "POST", contentType : "application/json", url : "${home}search/api/getSearchResult", data : JSON.stringify(data), dataType : 'json', timeout : 100000, success : function(data) { console.log("SUCCESS: ", data); display(data); }, error : function(e) { console.log("ERROR: ", e); display(e); }, done : function(e) { console.log("DONE"); } }); }


1.2 Spring controller to handle the Ajax request.


@Controller public class AjaxController { @ResponseBody @RequestMapping(value = "/search/api/getSearchResult") public AjaxResponseBody getSearchResultViaAjax(@RequestBody SearchCriteria search) { AjaxResponseBody result = new AjaxResponseBody(); //logic return result; } }


Ajax JSON Response in Spring MVC

Spring MVC provides an easy way to handle Ajax requests and send JSON responses. In this section, we will discuss how to configure Ajax in Spring MVC and create JSON responses.

Configuring Ajax in Spring MVC

To handle Ajax requests in Spring MVC, we need to configure the

DispatcherServlet

to enable handling of annotated controllers. We can do this by adding the following configuration in the

web.xml

file:




dispatcher


org.springframework.web.servlet.DispatcherServlet

contextConfigLocation /WEB-INF/spring/dispatcher-servlet.xml



dispatcher




Next, we need to create a Spring controller to handle the Ajax request. We can annotate the controller method with

@RequestMapping

and

@ResponseBody

to indicate that the method should handle Ajax requests and return a JSON response.

Creating JSON Response

To create a JSON response in Spring MVC, we can use the

@ResponseBody

annotation. This annotation indicates that the method should return the response body directly to the client instead of rendering a view.

We can create a JSON response by returning a Java object that can be serialized to JSON. Spring MVC will automatically serialize the object to JSON and send it as the response body.

Here’s an example of a Spring controller method that returns a JSON response:


@RequestMapping(value = "/getPerson", method = RequestMethod.GET) @ResponseBody public Person getPerson() { Person person = new Person(); person.setName("John"); person.setAge(30); return person; }


In this example, we create a

Person

object and set its name and age. We then return the

Person

object, which Spring MVC will automatically serialize to JSON and send as the response body.

In conclusion, Spring MVC provides an easy way to handle Ajax requests and send JSON responses. By configuring the

DispatcherServlet

and using the

@ResponseBody

annotation, we can create controllers that handle Ajax requests and return JSON responses.

Spring Components

Only the important classes will be displayed.

4.1

@RestController

to handle the Ajax request. Read the comments for self-explanatory.


package com.mkyong.web.controller; import java.util.ArrayList; import java.util.List; import javax.annotation.PostConstruct; import org.springframework.util.StringUtils; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import com.fasterxml.jackson.annotation.JsonView; import com.mkyong.web.jsonview.Views; import com.mkyong.web.model.AjaxResponseBody; import com.mkyong.web.model.SearchCriteria; import com.mkyong.web.model.User; @RestController public class AjaxController { List

users; // @ResponseBody, not necessary, since class is annotated with @RestController // @RequestBody - Convert the json data into object (SearchCriteria) mapped by field name. // @JsonView(Views.Public.class) - Optional, filters json data to display. @JsonView(Views.Public.class) @RequestMapping(value = "/search/api/getSearchResult") public AjaxResponseBody getSearchResultViaAjax(@RequestBody SearchCriteria search) { AjaxResponseBody result = new AjaxResponseBody(); if (isValidSearchCriteria(search)) { List

users = findByUserNameOrEmail(search.getUsername(), search.getEmail()); if (users.size() > 0) { result.setCode("200"); result.setMsg(""); result.setResult(users); } else { result.setCode("204"); result.setMsg("No user!"); } } else { result.setCode("400"); result.setMsg("Search criteria is empty!"); } //AjaxResponseBody will be converted into json format and send back to the request. return result; } private boolean isValidSearchCriteria(SearchCriteria search) { boolean valid = true; if (search == null) { valid = false; } if ((StringUtils.isEmpty(search.getUsername())) && (StringUtils.isEmpty(search.getEmail()))) { valid = false; } return valid; } // Init some users for testing @PostConstruct private void iniDataForTesting() { users = new ArrayList

(); User user1 = new User("mkyong", "pass123", "[email protected]", "012-1234567", "address 123"); User user2 = new User("yflow", "pass456", "[email protected]", "016-7654321", "address 456"); User user3 = new User("laplap", "pass789", "[email protected]", "012-111111", "address 789"); users.add(user1); users.add(user2); users.add(user3); } // Simulate the search function private List

findByUserNameOrEmail(String username, String email) { List

result = new ArrayList

(); for (User user : users) { if ((!StringUtils.isEmpty(username)) && (!StringUtils.isEmpty(email))) { if (username.equals(user.getUsername()) && email.equals(user.getEmail())) { result.add(user); continue; } else { continue; } } if (!StringUtils.isEmpty(username)) { if (username.equals(user.getUsername())) { result.add(user); continue; } } if (!StringUtils.isEmpty(email)) { if (email.equals(user.getEmail())) { result.add(user); continue; } } } return result; } }








4.2 The “json data” will be converted into this object, via

@RequestBody

.


package com.mkyong.web.model; public class SearchCriteria { String username; String email; //getters and setters }


4.2 Create a dummy class for

@JsonView

, to control what should be returned back to the request.


package com.mkyong.web.jsonview; public class Views { public static class Public {} }


4.3 User object for search function. Fields which annotated with

@JsonView

will be displayed.


package com.mkyong.web.model; import com.fasterxml.jackson.annotation.JsonView; import com.mkyong.web.jsonview.Views; public class User { @JsonView(Views.Public.class) String username; String password; @JsonView(Views.Public.class) String email; @JsonView(Views.Public.class) String phone; String address; //getters, setters and contructors }


4.4 This object will be converted into json format and return back to the request.


package com.mkyong.web.model; import java.util.List; import com.fasterxml.jackson.annotation.JsonView; import com.mkyong.web.jsonview.Views; public class AjaxResponseBody { @JsonView(Views.Public.class) String msg; @JsonView(Views.Public.class) String code; @JsonView(Views.Public.class) List

result; //getters and setters }



The


@JsonViewbelongs to Jackson library, not Spring framework.


Common Issues and Solutions

Debugging Ajax Issues in Spring MVC

When working with Ajax requests in Spring MVC, it is common to encounter issues related to the request not being sent or received properly. Here are some common issues and solutions:

• Incorrect URL: Ensure that the URL in the Ajax request matches the URL in the Spring MVC controller. Check for any typos or missing slashes in the URL.
• Missing Request Parameters: Check if all the required request parameters are being sent in the Ajax request. Use the browser’s developer tools to inspect the request and response headers and data.
• Cross-Origin Resource Sharing (CORS): If the Ajax request is being sent from a different domain than the one hosting the Spring MVC application, then CORS restrictions may apply. Check if the server is configured to allow CORS requests.

Optimizing JSON Response

Sending JSON data in Spring MVC can be optimized to improve the performance of the application. Here are some tips to optimize the JSON response:

• Minimize the JSON payload: Only send the required data in the JSON response. Remove any unnecessary data to reduce the payload size.
• Use GZIP compression: Compress the JSON response using GZIP compression to reduce the payload size and improve the response time.
• Use caching: Cache the JSON response on the client-side or server-side to reduce the number of requests and improve the response time.

By following these tips, we can optimize the JSON response and improve the performance of the Spring MVC application.

Client side

An AJAX usage implies a lot of code on a client side of a web-application. In this section I will demonstrate a basics which will help you to understand what steps to do for implementation of AJAX calls. Let’s examine case with creation of a new smartphone in the application.

First of all I need to add JQuery library to HTML page:

A main part of the HTML has one valuable update – extension of form action attribute was changed to .json

Create new Smartphone

Here you can create new Smartphone:

Producer:	Nokia iPhone HTC Samsung
Model:
Price:

Home page

And now, ladies and gentlemen, I wish to introduce a snippet of JQuery code for the creation of new smartphone:

$(document).ready(function() { $(‘#newSmartphoneForm’).submit(function(event) { var producer = $(‘#producer’).val(); var model = $(‘#model’).val(); var price = $(‘#price’).val(); var json = { “producer” : producer, “model” : model, “price”: price}; $.ajax({ url: $(“#newSmartphoneForm”).attr( “action”), data: JSON.stringify(json), type: “POST”, beforeSend: function(xhr) { xhr.setRequestHeader(“Accept”, “application/json”); xhr.setRequestHeader(“Content-Type”, “application/json”); }, success: function(smartphone) { var respContent = “”; respContent += ”

Smartphone was created: [“; respContent += smartphone.producer + ” : “; respContent += smartphone.model + ” : ” ; respContent += smartphone.price + “]

“; $(“#sPhoneFromResponse”).html(respContent); } }); event.preventDefault(); }); });

I’m not going to stop on this code and explain it in detail because you can read about AJAX and JQuery on official site.

Brief explanation: when someone want to submit the form with specified ID, all form fields are assigned to appropriate variables. After that a new JSON document is generated based on the form field variables. Then AJAX call is performed. It directed to URL which is specified in the action attribute of form tag. The JSON is used as a data which need to be processed. Type of the request is POST (it can vary depending on operation, e.g. for update it will has PUT value). In the beforeSend function I explicitly specify required headers for JSON format. In the end I formulate a response and insert it in DOM.

That’s it what related to creation of smartphone. The update of smartphone is the similar, just type of the request need to be changed.

Now let’s see how to work with DELETE type of requests. As previously I need to change extension of URLs to .json

Delete

A JQuery code for the DELETE operation will be a little bit distinct compared to POST and PUT.

$(document).ready(function() { var deleteLink = $(“a:contains(‘Delete’)”); $(deleteLink).click(function(event) { $.ajax({ url: $(event.target).attr(“href”), type: “DELETE”, beforeSend: function(xhr) { xhr.setRequestHeader(“Accept”, “application/json”); xhr.setRequestHeader(“Content-Type”, “application/json”); }, success: function(smartphone) { var respContent = “”; var rowToDelete = $(event.target).closest(“tr”); rowToDelete.remove(); respContent += ”

Smartphone was deleted: [“; respContent += smartphone.producer + ” : “; respContent += smartphone.model + ” : ” ; respContent += smartphone.price + “]

“; $(“#sPhoneFromResponse”).html(respContent); } }); event.preventDefault(); }); });

The first distinction is the selector for the element. In case with DELETE I want to work with links but not with forms. The type of the AJAX call is changed to DELETE value. There is no any data which is send with the request. And in the end I delete the row with the smartphone which need to be deleted.

Download Source Code

References

About Author

Comments

Thanks. tutorial solved my problem

Thanks.This tutorial solved my problem

Hi Mkyong,I always found your examples clear and good,Thanks lot!

Hey guy, what example! So far the best tutorial i’ve ever seen. Thanks!!!

Thanks for the article . I am quite late but while working on this code, I get following issue.Multiple markers at this line– PostConstruct cannot be resolvedto a type– PostConstruct cannot be resolvedto a type

Anyone know how to resolve this?

Hi, is it possible to save an image in this way? how can I do it? Do you have any example? Thank you

Thank you mkYong for providing this good example.

I am able to deploy and start jetty with this project.

But I am getting below content on hitting http://localhost:2222/spring4ajax/ not showing search page.

Could you/someone please help me here.

Directory: /spring4ajax/spring4-mvc-maven-ajax-example-1.0-SNAPSHOT.war 13184243 bytes Apr 8, 2020 3:58:31 PM

method post not allowed

how to do CRUD operating in Spring MVC in eclipse without refreshing the page and connection with database

when i “$ mvn jetty:run “in the git bush it shows “No plugin found for prefix ‘jetty”‘

Could you please explain how can i do the same if i’m sending and receiving the data in XML instead of json?

Thanks

good tutorial, but i integration in my project and show this{“readyState”: 4,“responseText”: ”Estado HTTP 405 – Request method ‘POST’ not supportedtype Informe de estado

mensaje Request method ‘POST’ not supported

descripción El método HTTP especificado no está permitido para el recurso requerido.

Pivotal tc Runtime 3.1.5.RELEASE/8.0.36.A.RELEASE“,“status”: 405,“statusText”: “Método No Permitido”}

Could you please explain to me what the “$” sign mean in the following line:

jQuery(document).ready(function($) {And also why this line doesn’t start like:$(document) ?Thanks in advance!

this is a good example, thanks.

Hi Mkyong,

I have two questions. First, How to create layout file?And other question, Can we add annotation to validation for view class. i don’t want to write isValidSearchCriteria method.

thanks.

i got the following error while i execute the code …

The server refused this request because the request entity is in a format not supported by the requested resource for the requested method.

“status”: 415,

“statusText”: “Unsupported Media Type”

this is a good example, thanks.

Thanks

Hi Mkyoung,i’m getting this error :HTTP ERROR 406 Not Acceptable.

i’m sure that the ‘result’ object from ‘AjaxResponseBody’ class having a value when returned back to ajax response but i always get that error.

I’m using:– spring 4.0.2– jackson 2.6.3– jetty server

HI Mkyong,I’m uable to run this project in Tomcat 8, I mean the Tomcat starts properly with this project, but when I hit the url, it gives me 404.

Thanks,Kapil

Hi Mkyong,

Am trying to get this application up and running in JBoss AS7 but am getting a 404 when accessing http://localhost:8080/spring4ajax/search/api/getSearchResult/

I have the same issue with one of my application which works well in Tomcat but not in JBoss AS7, just wondering if there is a workaround if you know off.

Thanks

Article is updated with wildfly-maven-plugin, use this command

mvn wildfly:deploy

to deploy this web application to WildFly.

I am new in javawhere should I run this command

1. 404 is resources not found. Make sure ‘spring4ajax’ is your deployed web context.

2. If you get this example and deploy directly, the default web context will be this – http://localhst:8080/spring4-mvc-maven-ajax-example-1.0-SNAPSHOT

3. To update the WildFly web context, try this tutorial – https://mkyong.com/maven/maven-deploy-web-application-to-wildfly/

P.S This web application is tested with WildFly 9, no error.

hey guys , find given solution to compile the project.

you need to add following plugin in pom.xml

maven-war-plugin

2.4

false

Hope it would work for you guys , cheers 🙂

Thanks, article is updated with maven-war-plugin.

still can not work please help.HTTP Status 500 – An exception occurred processing JSP page /welcome.jsp at line 11

can you try that link after starting jetty servermake sure your port should not be used before.http://localhost:8080/spring4ajax/

It is not compiling:

Error assembling WAR: webxml attribute is required (or pre-existing WEB-INF/web.xml if executing in update mode) -> [Help 1]

Fixed, article is updated with maven-war-plugin.

Raul ,add this in your pom.xml

maven-war-plugin

2.4

false

Jeez, this is not a tutorial, but rather a template. It’s 400+ lines of code and merely a dozen lines of explanation.

Where is the web.xml file ? I have the following error:

org.xml.sax.SAXParseException; systemId: file:/C:/DEV/apache-tomcat-8.0.28/webapps/spring4-mvc-maven-ajax-example-1.0-SNAPSHOT/WEB-INF/web.xml; lineNumber: 1; columnNumber: 2; Premature end of file.

at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(Unknown Source)at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source)at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source)at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(Unknown Source)at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(Unknown Source)at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)

For servlet container >= 3, web.xml is option. Code is updated, try clone the source code from GitHub again.

you need to add following plugin in pom.xml

maven-war-plugin

2.4

false

Hi Mkyong,

I reckon that you will find that using my library http://www.ajaxanywhere.com makes things a lot easier with a far more maintainable outcome. Ajaxanywhere is intended to provide declarative Ajax for apps that use server side rendering. Because it is declarative, by using HTML markup, you will find that you use very llittle to none javascript code. Please have a look at the examples: http://examples.ajaxanywhere.comI would appreciate your feedback a lot!Thanks!

Good stuff, but you should keep it more simple. Some details are not really needed here. For example, the @JsonView annotation only confused me more untill I figured it has nothing to do with the scope of this presentation. Just skip it.Also, some details are maybe missing. For example, in order to work, I had to add an extention in ajax url (“url: getSearchResult.ext”) and then add this in web.xml:

dispatcher*.ext

servlet-mappingservlet-name dispatcher /servlet-nameurl-pattern *.ext /url-pattern/servlet-mapping

Preparations

I need to modify the SmartphoneController class by removing methods which are not required any more. This is a first step of AJAX integration.

//imports are omitted @Controller @RequestMapping(value=”/smartphones”) public class SmartphoneController { @Autowired private SmartphoneService smartphoneService; @RequestMapping(value=”/create”, method=RequestMethod.GET) public ModelAndView createSmartphonePage() { ModelAndView mav = new ModelAndView(“phones/new-phone”); mav.addObject(“sPhone”, new Smartphone()); return mav; } @RequestMapping(value=”/create”, method=RequestMethod.POST, produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE) @ResponseBody public Smartphone createSmartphone(@RequestBody Smartphone smartphone) { return smartphoneService.create(smartphone); } @RequestMapping(value=”/edit/{id}”, method=RequestMethod.GET) public ModelAndView editSmartphonePage(@PathVariable int id) { ModelAndView mav = new ModelAndView(“phones/edit-phone”); Smartphone smartphone = smartphoneService.get(id); mav.addObject(“sPhone”, smartphone); return mav; } @RequestMapping(value=”/edit/{id}”, method=RequestMethod.PUT, produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE) @ResponseBody public Smartphone editSmartphone(@PathVariable int id, @RequestBody Smartphone smartphone) { smartphone.setId(id); return smartphoneService.update(smartphone); } @RequestMapping(value=”/delete/{id}”, method=RequestMethod.DELETE, produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE) @ResponseBody public Smartphone deleteSmartphone(@PathVariable int id) { return smartphoneService.delete(id); } @RequestMapping(value=””, method=RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE) @ResponseBody public List< Smartphone > allPhones() { return smartphoneService.getAll(); } @RequestMapping(value=””, method=RequestMethod.GET) public ModelAndView allPhonesPage() { ModelAndView mav = new ModelAndView(“phones/all-phones”); List< Smartphone > smartphones = new ArrayList< Smartphone >(); smartphones.addAll(allPhones()); mav.addObject(“smartphones”, smartphones); return mav; } }

You can compare the new version of the SmartphoneController with the older one. Methods which process PUT, POST, DELETE requests and return ModelAndView objects were removed. The methods were deleted because AJAX calls can be addressed directly to REST methods. Now the controller contains just two types of methods:

• The first type directs user to pages where CRUD operations can be performed.
• The second type performs CRUD operations (REST methods)

Project Dependencies


4.0.0


com.mkyong


spring4-mvc-maven-ajax-example
war
1.0-SNAPSHOT


spring4 mvc maven ajax example

1.8


4.2.2.RELEASE


2.6.3


1.1.3


1.7.12


1.2


3.1.0



org.springframework


spring-webmvc


${spring.version}




commons-logging


commons-logging







com.fasterxml.jackson.core


jackson-core


${jackson.version}




com.fasterxml.jackson.core


jackson-databind


${jackson.version}





javax.servlet


jstl


${jstl.version}





org.slf4j


jcl-over-slf4j


${jcl.slf4j.version}




ch.qos.logback


logback-classic


${logback.version}






javax.servlet


javax.servlet-api


${servletapi.version}


provided




org.apache.maven.plugins


maven-compiler-plugin


3.3


${jdk.version}

${jdk.version}


org.eclipse.jetty


jetty-maven-plugin


9.2.11.v20150529



10



/spring4ajax



org.apache.maven.plugins


maven-eclipse-plugin


2.10



true


true


2.0


spring4ajax


org.apache.maven.plugins


maven-war-plugin


2.6



false


org.wildfly.plugins


wildfly-maven-plugin


1.1.0.Alpha5



127.0.0.1
9990
admin
admin
spring4ajax.war



Refactoring Spring MVC

2.1 Create a POJO to store the Ajax POST data.


public class HostingForm { private boolean display; private boolean cdn; private boolean hosting; private boolean paas; private String whoisPattern; private long id; private String domain; private String name; private String desc; private String tags; private String affLink; private String imageUrl; private String favUrl; //getters and setters


2.2 Accept the Ajax POST data with

@RequestBody



@RestController //... @RequestMapping(value = "/path-to/hosting/save", method = RequestMethod.POST) public String updateHosting(@RequestBody HostingForm hostingForm) { //... }


With

@RequestBody

, Spring will maps the POST data to

HostingForm

POJO (by name) automatically. Done.

You mat interest at this tutorial – Complete Spring 4 MVC + Ajax Form Post example

References

About Author

Comments

i sending formdata to controller class. in controller how to access these data?

$(“button#submitMDRtable”).click(function(){var data = [];var minAmt, maxAmt, type, minCap, maxCap;$(“table tbody tr”).each(function(index) {minAmt = $(this).find(‘.minAmt’).text();maxAmt = $(this).find(‘.maxAmt’).text();type = $(this).find(‘.type’).text();minCap = $(this).find(‘.minCap’).text();maxCap = $(this).find(‘.maxCap’).text();//alert(minAmt+”–“+maxAmt+”–“+type+”–“+minCap+”–“+maxCap)//—->Form validation goes heredata.push({minAmt: minAmt,maxAmt: maxAmt,type: type,minCap: minCap,maxCap: maxCap});});submitFormData(data);console.log(data);});

function submitFormData(formData) {var url= ‘/mdrcharges’;alert(url);$.ajax({type: ‘POST’,data: formData,cache: false,processData: false,contentType: false,beforeSend: beforeSendHandler,url: url,success: function(result){if(result.success == true) {$(‘.alert-success’).show();$(‘.alert-danger’).hide();$(“#successmsg”).html(result.msg);setTimeout(function() {$(“.alert-success”).alert(‘close’);}, 10000);} else {$(‘.alert-danger’).show();$(‘.alert-success’).hide();$(“#error”).html(result.msg);setTimeout(function() {$(“.alert-danger”).alert(‘close’);}, 10000);}}});}

OK. This is an easy example, and everyone saw it a hundred times. But tell us what do you will do if you have here is a JSON:

{“abc”:{“sr”:”ok”,”citi”:[{“id”:”c2″,”value”:”london”},{…}…,{…}]}}

etc ?

Just send a POST request, along with your JSON data.

Spring MVC AJAX Hello World Example – Kiến thức cơ bản HTTP và AJAX

Bài đăng này đã không được cập nhật trong 2 năm

Khi tìm hiểu về giao thức HTTP mình có đọc 1 số bài hướng dẫn trả lời phỏng vấn về giao thức HTTP như:

Phương thức POST bảo mật hơn GET vì dữ liệu được gửi ngầm bằng mắt thường không thể nhìn thấy được


Phương thức GET luôn luôn nhanh hơn POST vì dữ liệu gửi đi được Browser giữ lại trong cache


Phương thức GET dữ liệu được gửi tường minh, chúng ta có thể thấy trên URL nên nó không bảo mật.

Các câu trả lời ở bên trên chưa chính xác là do bạn chưa hiểu đúng về giao thức HTTP

**Trong bài hướng dẫn này mình sẽ nói đến các vấn đề sau**

1) Các khái niệm cơ bản về giao thức HTTP (GET, POST)

2) Tạo 1 web application sử dụng Spring MVC với AJAX

Giao thức HTTP( Hyper Text Transfer Protocol) là gì ? HTTP là giao thức quy ước chung để cho 2 đối tượng A và B có thể giao thông ( giao tiếp ) với nhau. Cụ thể là giao tiếp với nhau bằng 1 định dạng sử dụng chữ (text)

Ta đã biết phép căn bản của phần mềm là 2 phép đọc (read) và ghi (write) dữ liệu (Phần mềm viết ra là để xử lý dữ liệu) – phép ghi còn tách ra làm 3 phép thêm, sửa, xóa. Khi người ta thiết kế ra giao thức HTTP cũng xoay quanh các phép căn bản này của phần mềm. Từ 4 phép căn bản này sẽ tạo ra 7 HTTP method:

• 4 phép đại diện cho đọc (read):

1. GET
2. Trace: đọc lỗi
3. Option
4. Head: đọc phần header

• 3 phép đại diện cho ghi (write):

1. PUT
2. POST
3. DELETE

Nhưng trong quá trình làm việc chúng ta gần như chỉ sử dụng 1 phép đại diện cho đọc là GET, 1 phép đại diện cho ghi là POST. Từ đây dẫn đến sự khác nhau giữa GET và POST:

1. Ví dụ A muốn gửi 1 thông điệp (message) rằng A muốn đọc dữ liệu (GET) của B, như vậy A không cần mang dữ liệu lên B. Nhưng khi A muốn gửi (POST) 1 bức ảnh đến B, A phải mang dữ liệu lên B. Như vậy GET đại diện cho phép đọc sẽ không có phần body mà chỉ có header, còn POST đại diện cho phép ghi sẽ có phần body (đưa dữ liệu vào body)
2. Sự khác nhau giữa cấu trúc của GET và POST sẽ ảnh hưởng đến điểm mạnh điểm yếu của POST và GET.

• GET sẽ
  
nhanh

  hơn POST: GET sẽ đi nhanh hơn POST trong môi trường mạng vì nó k có body. Phần server khi xử lý message này sẽ nhanh hơn vì GET chỉ có header (khi nói đến
  
nhanh

  ta phải nhắc đến 2 khía cạnh: traffic và performance)
• Điểm mạnh của POST là đưa được data lên. Nếu muốn đưa 1 đoạn video, 1 bức ảnh GET sẽ k thể nào làm được => Nhưng vì GET đi nhanh hơn nên người ta có xu hướng dùng GET nhiều hơn, thế nên những dữ liệu mà mang lên server đủ nhỏ thì người ta có thể chuyển dữ liệu theo đường GET
• GET và POST đều có tính bảo mật như nhau, vì đối với GET ta có thể sử dụng kỹ thuật ajax để parametter k hiển thị lên trên url

**Tạo 1 project sử dụng Spring MVC + Ajax bằng maven, server chạy bằng jetty **

Ajax là gì ? Ajax là một khái niệm có thể mới lạ với những bạn newbie mới học lập trình web nên đôi lúc các bạn nghĩ nó là một ngôn ngữ lập trình mới. Nhưng thực tế không như vậy, ajax là một kỹ thuật viết tắt của chữ AJAX = Asynchronous JavaScript and XML, đây là một công nghệ giúp chung ta tạo ra những Web động mà hoàn toàn không reload lại trang nên rất mượt và đẹp. Đối với công nghệ web hiện nay thì ajax không thể thiếu, nó là một phần làm nên sự sinh động cho website

Các công nghệ sẽ sử dụng trong phần hg dẫn này:

1. Spring 4.2.2.RELEASE
2. Jackson 2.6.3
3. Logback 1.1.3
4. jQuery 1.10.2
5. Maven 3
6. JDK 1.8
7. Tomcat 8 or Jetty 9
8. Eclipse 4.5
9. Boostrap 3

**Cấu trúc project **

**1)Project dependency: **


4.0.0


com.viblo


viblo-spring-learn-ajax
war
1.0-SNAPSHOT


viblo-spring-learn-ajax Maven Webapp


http://maven.apache.org

1.8


4.2.2.RELEASE


2.6.3


1.1.3


1.7.12


1.2


3.1.0



org.springframework


spring-webmvc


${spring.version}




commons-logging


commons-logging







com.fasterxml.jackson.core


jackson-core


${jackson.version}




com.fasterxml.jackson.core


jackson-databind


${jackson.version}





javax.servlet


jstl


${jstl.version}





org.slf4j


jcl-over-slf4j


${jcl.slf4j.version}




ch.qos.logback


logback-classic


${logback.version}






javax.servlet


javax.servlet-api


${servletapi.version}


provided





viblo-spring-learn-ajax

org.apache.maven.plugins


maven-surefire-plugin


2.12.4



true


-Xmx2524m


org.apache.maven.plugins


maven-compiler-plugin


3.1


1.8

1.8


UTF-8


true



-XDignore.symbol.file



org.eclipse.jetty


jetty-maven-plugin


9.3.0.M1



-Xmx2048m -Xms1536m -XX:PermSize=128m -XX:MaxPermSize=512m


manual




lib


${basedir}/target/viblo-spring-learn-ajax/WEB-INF/lib




8080
60000




${basedir}/src/main/webapp


${basedir}/src/main/webapp/WEB-INF/web.xml


${basedir}/target/classes



2)AjaxController AjaxController sẽ xử lý các ajax request từ phía client như thêm, hoặc tìm kiếm ! Sau đó trả về kết quả dưới dạng json cho client.


@Controller @RequestMapping("/home") public class AjaxController { private List listPerson = new ArrayList (); @RequestMapping(method = RequestMethod.GET) public ModelAndView home() { ModelAndView mv = new ModelAndView("web.home"); return mv; } @RequestMapping(value = "/addnew", method = RequestMethod.GET) public @ResponseBody String addNew(HttpServletRequest request) { String name = request.getParameter("name"); String age = request.getParameter("age"); Person person = new Person(name, Integer.parseInt(age)); listPerson.add(person); ObjectMapper mapper = new ObjectMapper(); String ajaxResponse = ""; try { ajaxResponse = mapper.writeValueAsString(person); } catch (JsonProcessingException e) { e.printStackTrace(); } return ajaxResponse; } @RequestMapping(value = "/search", method = RequestMethod.GET) public @ResponseBody String searchPerson(HttpServletRequest request) { String query = request.getParameter("name"); Person person = searchPersonByName(query); ObjectMapper mapper = new ObjectMapper(); String ajaxResponse = ""; try { ajaxResponse = mapper.writeValueAsString(person); } catch (JsonProcessingException e) { e.printStackTrace(); } return ajaxResponse; } public Person searchPersonByName(String query) { for (Person p : listPerson) { if (p.getName().equals(query)) { return p; } } return null; }

**3)Model Class ** Person class có nhiệm vụ đóng gói dữ liệu của người dùng nhập vào hoặc dữ liệu được trả về của server !


public class Person { private String name; private int age; public Person() { } public Person(String name, int age) { this.name=name; this.age=age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } }


**4)Jquery Ajax **
Trong file JSP, ta tạo 2 form thêm và tìm kiếm đơn giản gửi ajax request bằng

$.ajax



<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>


Add New Person

Search Person by name

Click on the button to load /jquery/result.html file −

STAGE

Ở đây load() khởi tạo một Ajax request tới URL là file “result.html” .Sau khi tải tệp này, tất cả nội dung sẽ được điền vào bên trong

được gắn thẻ với giai đoạn ID. Giả sử, tệp /jquery/result.html của chúng tôi chỉ có một dòng HTML

2. Phương thức getJSON()

Cú pháp

[selector].getJSON( URL, [data], [callback] );

Trong đó:

URL – URL của tài nguyên phía máy chủ được liên hệ qua phương thức GET

DATA – Một đối tượng có các thuộc tính đóng vai trò là cặp key/value được sử dụng để xây dựng chuỗi truy vấn được thêm vào URL hoặc chuỗi truy vấn được định dạng sẵn và được mã hóa

Callback – Một chức năng được gọi khi yêu cầu hoàn thành. Giá trị dữ liệu phản hồi dưới dạng chuỗi JSON được truyền dưới dạng tham số đầu tiên của request và tham số thứ hai là trạng thái.

Live Demo

src = "https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js">

Click on the button to load result.json file −

STAGE

Ở đây, phương thức tiện ích JQuery getJSON () khởi tạo một yêu cầu Ajax đến tệp URL result.json được chỉ định. Sau khi tải tệp này, tất cả nội dung sẽ được chuyển đến chức năng gọi lại, cuối cùng sẽ được đưa vào bên trong

được gắn thẻ với giai đoạn ID

3. Phương thức get(), post()

Cú pháp

$.get( url, [data], [callback], [type] )

$.post( url, [data], [callback], [type] )

Trong đó:

URL – Là chuỗi chưa URL để gửi request

Data – Tham số tùy chọn đại diện cho các cặp key/value sẽ được gửi đến máy chủ

Callback – Là một chức năng được gọi khi yêu cầu hoàn thành

Type – Tham số tùy chọn này đại diện cho loại dữ liệu được trả về cho hàm gọi lại: “xml”, “html”, “script”, “json”, “jsonp” hoặc “text”.

src = "https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js">

Click on the button to load result.html file −

STAGE

value = "Load Data" />

src = "https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js">

Click on the button to load result.html file −

STAGE

4. Phương thức ajax()

Cú pháp

jQuery.ajax( options )

Trong đó:

Options: Là một tập hợp các cặp key/value cấu hình yêu cầu Ajax

src = "https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js">

Click on the button to load result.html file:

STAGE

Spring MVC – Refactoring a jQuery Ajax Post example

Reviewing a jQuery Ajax form POST and Spring MVC example, find out the following patterns :

In Spring MVC, use

@RequestParam

to accept the Ajax POST data.


@RequestMapping(value = "/path-to/hosting/save", method = RequestMethod.POST) @ResponseBody public String saveHosting( @RequestParam int id, @RequestParam String domain, @RequestParam String name, @RequestParam String desc, @RequestParam String tags, @RequestParam String afflink, @RequestParam boolean display, @RequestParam boolean hosting, @RequestParam boolean cdn, @RequestParam boolean paas, @RequestParam String imageUrl, @RequestParam String favUrl, @RequestParam String whoisPattern ) { //...do something }


The above code is working fine, just a bit weird and hard to maintain. Both Javascript

$.post

and Spring MVC

@RequestParam

is dealing with too many parameters.

Understanding Spring MVC

Spring MVC is a web application framework developed by the Spring Framework. It provides a model-view-controller (MVC) architecture that is used to develop web applications. The framework provides a lot of features that make the development of web applications easy and efficient. In this section, we will discuss the role of Spring MVC in web applications and its key features.

Role of Spring MVC in Web Applications

Spring MVC is a powerful framework that provides a lot of features that are essential for developing web applications. The framework provides a model-view-controller architecture that is used to separate the application into three parts:

• Model: This represents the data and business logic of the application.
• View: This represents the user interface of the application.
• Controller: This is responsible for handling the user requests, processing the data, and returning the response.

The main role of Spring MVC in web applications is to provide a flexible and powerful framework that can be used to develop web applications that are easy to maintain and extend. The framework provides a lot of features that make the development process easy and efficient.

Key Features of Spring MVC

Spring MVC provides a lot of key features that make it a powerful framework for developing web applications. Some of the key features are:

• Powerful Request Handling: Spring MVC provides a powerful request handling mechanism that can handle different types of requests, including GET, POST, PUT, DELETE, and more.
• Flexible Configuration: Spring MVC provides a flexible configuration mechanism that allows developers to configure the framework according to their needs.
• Built-in Validation: Spring MVC provides built-in validation support that allows developers to validate the user input easily.
• Internationalization Support: Spring MVC provides internationalization support that allows developers to develop applications that can be easily localized.
• Integration with Other Technologies: Spring MVC can be easily integrated with other technologies, such as Hibernate, MyBatis, and more.

In conclusion, Spring MVC is a powerful framework that provides a lot of features that make the development of web applications easy and efficient. The framework provides a model-view-controller architecture that is used to separate the application into three parts: model, view, and controller. The framework provides a lot of key features that make it a powerful framework for developing web applications.

You just search Person: " + data.name + "

"; $("#ajax-response").html(result); } else { var result = "

No person found

"; $("#ajax-response").html(result); } }, error : function(e) { console.log("ERROR: ", e); } }); }





5)Demo
Bật terminal hoặc lên, đưa con trỏ vào vị trí của project và gõ lệnh

mvn jetty:run


**5.1) Nhập tên và tuổi **

**5.2) Kết quả ajax trả về từ server **

Ta đã sử dụng HTTP method GET nhưng dữ liệu vẫn k bị hiển thị lên url => việc nói POST bảo mật hơn GET vì dữ liệu không được đưa lên url là chưa đúng !


jQuery Ajax

In JSP, create a simple search form and send the form request with jQuery

$.ajax

.


<%@page session="false"%> <%@taglib prefix="spring" uri="http://www.springframework.org/tags"%> <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>


Search Form

Username

Email

Search





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