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These are the user uploaded subtitles that are being translated: 1 1 00:00:01,497 --> 00:00:02,533 In this video, 2 2 00:00:02,533 --> 00:00:05,700 we're going to cover setter injection. 3 3 00:00:06,837 --> 00:00:09,014 So we've already covered constructor injection 4 4 00:00:09,014 --> 00:00:10,528 in the previous videos. 5 5 00:00:10,528 --> 00:00:14,695 And this video will focus on making use of setter injection. 6 6 00:00:17,750 --> 00:00:19,628 So with setter injection, 7 7 00:00:19,628 --> 00:00:21,794 this is where the spring framework will inject 8 8 00:00:21,794 --> 00:00:25,961 your dependencies by calling setter methods on your class. 9 9 00:00:28,467 --> 00:00:30,449 So looking at the development process, 10 10 00:00:30,449 --> 00:00:33,822 and again, I love to do things step-by-step. 11 11 00:00:33,822 --> 00:00:35,058 The first thing we'll have to do, 12 12 00:00:35,058 --> 00:00:36,389 or the first step we'll have is 13 13 00:00:36,389 --> 00:00:40,503 creating the setter methods in our class for injections. 14 14 00:00:40,503 --> 00:00:44,223 Then the second step is configuring the dependency 15 15 00:00:44,223 --> 00:00:46,973 in the Spring configuration file. 16 16 00:00:50,792 --> 00:00:53,213 Okay, so let's take a look at step one, 17 17 00:00:53,213 --> 00:00:54,797 creating the setter method. 18 18 00:00:54,797 --> 00:00:58,160 So we'll have this new class called CricketCoach. 19 19 00:00:58,160 --> 00:00:59,959 We're going to explore a new sport here. 20 20 00:00:59,959 --> 00:01:03,067 So CricketCoach, they'll have a private field, 21 21 00:01:03,067 --> 00:01:05,198 they'll have a no-argument constructor, 22 22 00:01:05,198 --> 00:01:06,976 and then we'll have a setter method 23 23 00:01:06,976 --> 00:01:08,965 for setFortuneService. 24 24 00:01:08,965 --> 00:01:11,890 This is the method that will be called by Spring 25 25 00:01:11,890 --> 00:01:13,846 when they inject the dependency 26 26 00:01:13,846 --> 00:01:15,763 using setter injection. 27 27 00:01:19,093 --> 00:01:21,282 So in step two, we have to configure 28 28 00:01:21,282 --> 00:01:22,683 the dependency injection 29 29 00:01:22,683 --> 00:01:24,447 in our Spring config file. 30 30 00:01:24,447 --> 00:01:26,590 So up top, we have our FortuneService, 31 31 00:01:26,590 --> 00:01:28,433 like from the previous videos. 32 32 00:01:28,433 --> 00:01:30,130 And now here, on the bottom, 33 33 00:01:30,130 --> 00:01:32,202 we'll have this myCricketCoach. 34 34 00:01:32,202 --> 00:01:35,438 We inject the dependency using setter injection. 35 35 00:01:35,438 --> 00:01:37,007 So here we say property. 36 36 00:01:37,007 --> 00:01:39,666 We give the name of the property, fortuneService, 37 37 00:01:39,666 --> 00:01:42,422 and then the ref myFortuneService. 38 38 00:01:42,422 --> 00:01:44,494 And the ref refers to the bean 39 39 00:01:44,494 --> 00:01:49,421 that was defined a little earlier in this example. 40 40 00:01:49,421 --> 00:01:52,691 Now we have property name="fortuneService". 41 41 00:01:52,691 --> 00:01:54,296 What Spring will actually do is 42 42 00:01:54,296 --> 00:01:56,074 it'll take that property name, 43 43 00:01:56,074 --> 00:01:58,542 and call the setter method on your class 44 44 00:01:58,542 --> 00:01:59,914 for that given property. 45 45 00:01:59,914 --> 00:02:01,830 So they'll look for a public method 46 46 00:02:01,830 --> 00:02:03,913 called setFortuneService. 47 47 00:02:04,786 --> 00:02:07,776 So Spring will actually call the setFortuneService, 48 48 00:02:07,776 --> 00:02:11,747 and they'll pass in that value for that call. 49 49 00:02:11,747 --> 00:02:15,588 So, in general, any property name you have, 50 50 00:02:15,588 --> 00:02:19,073 Spring will attempt to make a call to the setter method 51 51 00:02:19,073 --> 00:02:20,658 for that given property. 52 52 00:02:20,658 --> 00:02:23,571 So if I had a property name BestAthlete, 53 53 00:02:23,571 --> 00:02:25,419 Spring will look for a method called 54 54 00:02:25,419 --> 00:02:28,145 public void setBestAthlete. 55 55 00:02:28,145 --> 00:02:29,973 So, it takes that property name, 56 56 00:02:29,973 --> 00:02:32,349 the first letter of that property, 57 57 00:02:32,349 --> 00:02:33,580 and makes it a capital, 58 58 00:02:33,580 --> 00:02:37,163 and then it makes a method call on the fly. 59 59 00:02:38,212 --> 00:02:40,974 So this is how Spring will process your config file. 60 60 00:02:40,974 --> 00:02:44,043 So up top, we have the bean ID of myFortuneService. 61 61 00:02:44,043 --> 00:02:45,465 And like we've seen before, 62 62 00:02:45,465 --> 00:02:47,921 Spring simply creates an instance 63 63 00:02:47,921 --> 00:02:49,626 of your FortuneService by using 64 64 00:02:49,626 --> 00:02:52,972 the new keyword for the no-argument constructor. 65 65 00:02:52,972 --> 00:02:54,932 Then for our CricketCoach, 66 66 00:02:54,932 --> 00:02:57,493 Spring will create a new CricketCoach 67 67 00:02:57,493 --> 00:02:59,606 using its no-argument constructor, 68 68 00:02:59,606 --> 00:03:02,215 and then it'll inject that dependency 69 69 00:03:02,215 --> 00:03:04,115 by calling the setter method. 70 70 00:03:04,115 --> 00:03:05,782 So whatever the property name is, 71 71 00:03:05,782 --> 00:03:08,259 in this case the property name is FortuneService, 72 72 00:03:08,259 --> 00:03:11,325 Spring will call setFortuneService, 73 73 00:03:11,325 --> 00:03:14,499 and they'll pass in a reference to that given bean. 74 74 00:03:14,499 --> 00:03:16,954 And that's what happens behind the scenes 75 75 00:03:16,954 --> 00:03:20,787 when Spring processes your configuration file. 6306