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These are the user uploaded subtitles that are being translated: 1 1 00:00:01,142 --> 00:00:02,128 In this video, 2 2 00:00:02,128 --> 00:00:04,383 I'm gonna give you a behind the scenes tour 3 3 00:00:04,383 --> 00:00:05,550 of Spring MVC. 4 4 00:00:09,444 --> 00:00:12,551 What are the components of a Spring MVC application? 5 5 00:00:12,551 --> 00:00:14,551 Basically it's a collection of web pages 6 6 00:00:14,551 --> 00:00:16,316 to layout your UI components. 7 7 00:00:16,316 --> 00:00:18,799 It's also a collection of Spring beans, 8 8 00:00:18,799 --> 00:00:21,323 for controlling, handling services, 9 9 00:00:21,323 --> 00:00:22,567 and so on. 10 10 00:00:22,567 --> 00:00:25,035 And then finally you have your Spring configuration. 11 11 00:00:25,035 --> 00:00:28,847 You can choose XML, Annotations, or pure Java. 12 12 00:00:28,847 --> 00:00:31,008 And those are kinda the main components 13 13 00:00:31,008 --> 00:00:33,341 of a Spring MVC application. 14 14 00:00:34,800 --> 00:00:37,711 line:15% Now, how does Spring MVC work behind the scenes? 15 15 00:00:37,711 --> 00:00:39,351 line:15% In a previous video I showed you this 16 16 00:00:39,351 --> 00:00:41,799 line:15% little diagram here of the process model. 17 17 00:00:41,799 --> 00:00:43,353 line:15% What I wanna do is actually take this 18 18 00:00:43,353 --> 00:00:45,926 line:15% little process model and kind of break it down, 19 19 00:00:45,926 --> 00:00:47,757 line:15% and kinda dig into it a little bit, 20 20 00:00:47,757 --> 00:00:49,413 line:15% and kinda go step-by-step. 21 21 00:00:49,413 --> 00:00:51,319 line:15% Do a little deep dive on how the 22 22 00:00:51,319 --> 00:00:53,402 line:15% whole process flow works. 23 23 00:00:56,273 --> 00:00:57,845 line:15% Everything starts off with that first 24 24 00:00:57,845 --> 00:01:00,142 line:15% incoming request and it encounters something 25 25 00:01:00,142 --> 00:01:01,694 line:15% called a front controller. 26 26 00:01:01,694 --> 00:01:03,925 line:15% So the front controller is known as 27 27 00:01:03,925 --> 00:01:05,851 line:15% the dispatcher servelet. 28 28 00:01:05,851 --> 00:01:07,848 line:15% This front controller's actually part 29 29 00:01:07,848 --> 00:01:09,512 line:15% of the Spring framework. 30 30 00:01:09,512 --> 00:01:13,094 line:15% It's already developed by the Spring development team 31 31 00:01:13,094 --> 00:01:15,067 line:15% so you don't have to create this. 32 32 00:01:15,067 --> 00:01:16,987 line:15% This is part of the Spring jar files 33 33 00:01:16,987 --> 00:01:17,828 line:15% that you download, 34 34 00:01:17,828 --> 00:01:18,955 line:15% so it's given to you for free. 35 35 00:01:18,955 --> 00:01:21,673 line:15% So out of the box you have his front controller. 36 36 00:01:21,673 --> 00:01:23,051 line:15% What this front controller will do 37 37 00:01:23,051 --> 00:01:25,172 line:15% is it will actually delegate the request 38 38 00:01:25,172 --> 00:01:27,694 line:15% to some other objects or items 39 39 00:01:27,694 --> 00:01:29,828 line:15% here in our system. 40 40 00:01:29,828 --> 00:01:33,089 line:15% As a developer, you will create 41 41 00:01:33,089 --> 00:01:36,756 line:15% the model, the view, and the controller MVC. 42 42 00:01:38,515 --> 00:01:41,044 line:15% So the model objects are in orange. 43 43 00:01:41,044 --> 00:01:43,394 line:15% The model objects contain data. 44 44 00:01:43,394 --> 00:01:44,687 line:15% The view templates, 45 45 00:01:44,687 --> 00:01:45,786 line:15% that are in dark green, 46 46 00:01:45,786 --> 00:01:48,184 line:15% that's your actual JSP page, 47 47 00:01:48,184 --> 00:01:50,051 line:15% or your view page to actually 48 48 00:01:50,051 --> 00:01:51,599 line:15% render the data. 49 49 00:01:51,599 --> 00:01:52,483 line:15% And then C, 50 50 00:01:52,483 --> 00:01:54,376 line:15% the controller classes that's in yellow, 51 51 00:01:54,376 --> 00:01:56,346 line:15% that's your actual business logic 52 52 00:01:56,346 --> 00:01:58,391 line:15% or your processing logic. 53 53 00:01:58,391 --> 00:02:00,232 line:15% Coming up next, I'll actually talk about 54 54 00:02:00,232 --> 00:02:03,482 line:15% each one of these components in detail. 55 55 00:02:05,454 --> 00:02:07,300 line:15% Let's start with controller. 56 56 00:02:07,300 --> 00:02:10,311 line:15% So when the front controller has a request, 57 57 00:02:10,311 --> 00:02:12,517 line:15% it delegates the request to the controller. 58 58 00:02:12,517 --> 00:02:13,562 line:15% That's in yellow. 59 59 00:02:13,562 --> 00:02:17,050 line:15% The controller is the code that you will actually create. 60 60 00:02:17,050 --> 00:02:18,999 line:15% Basically in this controller, 61 61 00:02:18,999 --> 00:02:21,194 line:15% this contains your business logic. 62 62 00:02:21,194 --> 00:02:23,181 line:15% So this is where you'll handle the request 63 63 00:02:23,181 --> 00:02:25,057 line:15% where you'll maybe read some form data 64 64 00:02:25,057 --> 00:02:26,232 line:15% then you'll take this data 65 65 00:02:26,232 --> 00:02:27,820 line:15% and store it or retrieve it. 66 66 00:02:27,820 --> 00:02:29,856 line:15% You may store it into a database or 67 67 00:02:29,856 --> 00:02:32,239 line:15% retrieve information from a web service. 68 68 00:02:32,239 --> 00:02:34,185 line:15% Basically, once you have your data 69 69 00:02:34,185 --> 00:02:35,320 line:15% and you're using it, 70 70 00:02:35,320 --> 00:02:36,655 line:15% then you can take that data 71 71 00:02:36,655 --> 00:02:38,211 line:15% and place it into the model. 72 72 00:02:38,211 --> 00:02:40,496 line:15% So the model is just a container for your data 73 73 00:02:40,496 --> 00:02:42,538 line:15% and then you pass it back to the appropriate 74 74 00:02:42,538 --> 00:02:43,804 line:15% view template. 75 75 00:02:43,804 --> 00:02:45,631 line:15% So again, your controller, 76 76 00:02:45,631 --> 00:02:46,932 line:15% code that you create, 77 77 00:02:46,932 --> 00:02:48,804 line:15% contains your business logic, 78 78 00:02:48,804 --> 00:02:51,387 line:15% and it handles the web request. 79 79 00:02:52,338 --> 00:02:54,009 line:15% So let's talk about the model. 80 80 00:02:54,009 --> 00:02:55,353 line:15% As I mentioned earlier, 81 81 00:02:55,353 --> 00:02:57,416 line:15% the model contains your data. 82 82 00:02:57,416 --> 00:02:58,960 line:15% So when your controller goes off 83 83 00:02:58,960 --> 00:03:01,538 line:15% and performs an operation to retrieve data 84 84 00:03:01,538 --> 00:03:04,304 line:15% from a backend system, like a database or web service, 85 85 00:03:04,304 --> 00:03:05,373 line:15% or a Spring Bean, 86 86 00:03:05,373 --> 00:03:09,179 line:15% you can take that data and place it into the model. 87 87 00:03:09,179 --> 00:03:11,029 line:15% So the model again is your container, 88 88 00:03:11,029 --> 00:03:12,648 line:15% like your suitcase or your luggage, 89 89 00:03:12,648 --> 00:03:15,756 line:15% for shipping data between various parts 90 90 00:03:15,756 --> 00:03:18,320 line:15% of your Spring MVC application. 91 91 00:03:18,320 --> 00:03:20,707 line:15% So that model data will actually get passed 92 92 00:03:20,707 --> 00:03:22,459 line:15% over to the view template 93 93 00:03:22,459 --> 00:03:23,636 line:15% and they can actually handle that 94 94 00:03:23,636 --> 00:03:25,364 line:15% for displaying the data. 95 95 00:03:25,364 --> 00:03:26,992 line:15% That's kinda where we're at right now. 96 96 00:03:26,992 --> 00:03:29,276 line:15% So the view template. 97 97 00:03:29,276 --> 00:03:31,559 line:15% The most common view template that you'll use 98 98 00:03:31,559 --> 00:03:32,892 line:15% is JSP and JSTL. 99 99 00:03:34,192 --> 00:03:35,988 line:15% Spring MVC is very flexible. 100 100 00:03:35,988 --> 00:03:38,175 line:15% There's many different view template types. 101 101 00:03:38,175 --> 00:03:39,656 line:15% I'll talk about that in a second. 102 102 00:03:39,656 --> 00:03:43,174 line:15% But for now let's just think about JSP, JSTL. 103 103 00:03:43,174 --> 00:03:46,787 line:15% This model data comes over to your view template 104 104 00:03:46,787 --> 00:03:50,931 line:15% and then your JSP page can read that model data 105 105 00:03:50,931 --> 00:03:52,211 line:15% and display it. 106 106 00:03:52,211 --> 00:03:54,394 line:15% So, say for example, 107 107 00:03:54,394 --> 00:03:56,134 line:15% you have a list of students, 108 108 00:03:56,134 --> 00:03:57,887 line:15% or list of products, 109 109 00:03:57,887 --> 00:04:01,050 line:15% then your JSP page can create a table 110 110 00:04:01,050 --> 00:04:02,861 line:15% to display that product list 111 111 00:04:02,861 --> 00:04:04,724 line:15% or that student list. 112 112 00:04:04,724 --> 00:04:07,303 line:15% Or, say for example, somebody is signing 113 113 00:04:07,303 --> 00:04:08,835 line:15% up for an airline flight, 114 114 00:04:08,835 --> 00:04:10,789 line:15% or is signing up for a class, 115 115 00:04:10,789 --> 00:04:13,175 line:15% then your view template, 116 116 00:04:13,175 --> 00:04:15,333 line:15% or your page can give them a confirmation, 117 117 00:04:15,333 --> 00:04:17,315 line:15% hey, you're registered for the class, 118 118 00:04:17,315 --> 00:04:19,213 line:15% here's your confirmation number. 119 119 00:04:19,213 --> 00:04:20,862 line:15% So that's the idea of the view template. 120 120 00:04:20,862 --> 00:04:22,886 line:15% It's basically a JSP page 121 121 00:04:22,886 --> 00:04:25,803 line:15% that will provide data to the user. 122 122 00:04:28,804 --> 00:04:30,271 Now as I mentioned, 123 123 00:04:30,271 --> 00:04:33,439 Spring MVC is very flexible on the view templates. 124 124 00:04:33,439 --> 00:04:35,428 There's actually other view templates 125 125 00:04:35,428 --> 00:04:36,384 that are supported, 126 126 00:04:36,384 --> 00:04:38,581 so if you don't wanna use JSP, 127 127 00:04:38,581 --> 00:04:40,229 you can make use of some other templates 128 128 00:04:40,229 --> 00:04:43,979 like Thymeleaf, Groovy, Velocity, Freemarker, 129 129 00:04:44,899 --> 00:04:46,442 the list goes on. 130 130 00:04:46,442 --> 00:04:49,347 You can plug in all different types of view templates. 131 131 00:04:49,347 --> 00:04:51,534 If you'd like to get details on this, 132 132 00:04:51,534 --> 00:04:53,501 go to this link I have on the screen, 133 133 00:04:53,501 --> 00:04:56,974 luv2code.com/spring-mvc-views. 134 134 00:04:56,974 --> 00:05:00,487 This'll redirect you to the official Spring documentation 135 135 00:05:00,487 --> 00:05:01,946 and you can get more information 136 136 00:05:01,946 --> 00:05:03,508 on the various other templates 137 137 00:05:03,508 --> 00:05:06,258 that are out there and available. 138 138 00:05:08,178 --> 00:05:09,011 Alright, good. 139 139 00:05:09,011 --> 00:05:10,977 This is a quick behind the scenes view 140 140 00:05:10,977 --> 00:05:12,300 of Spring MVC. 141 141 00:05:12,300 --> 00:05:14,975 You learned about the model, the view, the controller 142 142 00:05:14,975 --> 00:05:17,059 and a conceptual theoretical level. 143 143 00:05:17,059 --> 00:05:18,959 In the following videos we're gonna 144 144 00:05:18,959 --> 00:05:20,240 start getting our hands dirty 145 145 00:05:20,240 --> 00:05:22,292 and setting up our environment 146 146 00:05:22,292 --> 00:05:24,942 and then starting to write some code. 147 147 00:05:24,942 --> 00:05:26,775 So I'll see you there. 12925