- Getting Started 5:55
- Introducing Spring Data REST 6:03
- Entities and Repositories Review 9:28
- Abstract Classes 6:48
- Populating and Relationships 15:39
- Paging 7:12
- Exploring Your API With New Tools - Postman 7:55
- Exploring Your API With New Tools - HAL Browser 3:58
- Versioning 8:52
- Validation 8:31
- Adding Users 11:51
- Adding Authentication 10:35
- Authorizing Deletions 6:56
- Events 7:57
- Wrapping Up 1:18
Preview
Video Player
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Paging
7:12Let's learn what to do when you have the awesome problem of too much data. We'll also explore custom search queries.
Okay, so we have a good problem, right?
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We have way too much data.
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Now a typical solution to this is
that I introduced paged results and
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guess what, it's super easy to do.
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So let's pop over to the CourseRepository.
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Now remember this is what's
generating our controllers, right.
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So let's pop over here, and
if we simply change this from
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CrudRepository to
PagingandSortingRepository.
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And then, let's also do that for reviews
while we're in here because we're probably
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gonna have a lot of these too,
at least hopefully, right?
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And if we swing down here and
we reboot our server, I'm gonna ahead and
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click this Reboot button.
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Let's let this go.
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Awesome, so now if we flip over back to
our courses page, if I refresh this, if
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we scroll down, we will see that there is
a lot of new things here at the bottom.
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Namely first, right?
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So this is the first page and
there's only 20.
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So right, so there's only 20 on this page.
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It still kind of seems like a lot but
there's only 20 and
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it shows the next page which is page 1 and
it shows the last page.
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Pretty cool, right?
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Now let's think about this for
a minute, what if the users of our API,
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like our other teams, what if they were
trying to add a feature to find all
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the courses with a certain word in it?
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I guess what they'd have to do now right
is search through each of these pages.
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That'd be a bummer, right?
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Well again, no surprise.
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This can just happen.
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Okay, so let me show you.
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So, if you head over back
to your course repository,
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we can just add a new query here, right?
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And if we use the standard
naming conventions,
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our query will just be exposed.
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So what do we say we wanted?
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Right.
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Let's say that we wanted to find all
the courses with a certain word in
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their title.
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So to do that, what we'll do is we'll add
a method that returns a page of courses.
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And the proper naming thing,
we're gonna say, findByTitleContaining.
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You probably remember this from spring
data, findByTitle containing, right.
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And we're gonna pass in
the parameter of title,
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parameter of a named query param there.
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And it's going to be the title.
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And then finally we're
gonna pass in an iterator.
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It will get an interior.
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Expect an iterator.
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Okay.
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Give us some more space there.
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There we go.
So,
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again a special name
findByTitleContaining,
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title being the field.
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And we're gonna say,
call it title when it comes across.
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Watch this.
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So, we're gonna restart and
refresh the course.
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Pop up over here.
If we take a look and
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we go again down all the way to the
bottom, we'll see here that there's this
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new search item that's available, so
that says that we can search on courses.
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So let's bring that up and
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again it's just added that automatically
because we have something there.
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And now there's a thing called
findByTitleContaining and
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it shows you what you can do here,
what parameters it takes.
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This is a templated, right, so
this is a templated search.
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So we're gonna go ahead and let's do this,
let's say findByTitleContaining.
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And the query parameter that we're gonna
pass is title and we want it to start with
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something, whatever, let's say,
Java lets see what, what comes up.
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Here is all of the Java reports,
look at that?
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Looks like our database loader has
the same number of things, I'm assuming.
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So let's add one more on here.
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And let's say we wanna
learn about spring HATEOAS.
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So let's refresh this.
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That will happen if you're generating
data and they have the same.
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So the trick that kind of isn't working
for the the different modelos there.
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So we rebooted this.
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Let's go ahead and look again for
everything containing java.
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There we go.
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See that the titles are different now.
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Java 9, different course numbers.
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There we go.
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And also look, it's still paged, right?
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So we know that there's only 18 on this.
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There's only 1 page.
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But isn't that cool?
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It's still paged.
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Search results, so what if we didn't
like this findByTitleContaining?
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What if that seems a little bit
awkward to use in a REST world?
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So one thing that you can do, and you can
do this actually with just about anything
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that gets generated over here, is we
can change what this is displayed as.
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So if we use the annotation RestResource,
we can say that the rel, you
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know this is what the the link is called
in the search there, that's available.
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Since we're on a search here.
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I'm sorry,
back here in the search page here.
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We'll see that this is the REL here,
findByTitleContaining.
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So we can change that
to be title-contains.
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And we can also even
change the path to it.
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So let's make that read,
let's say instead of find,
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let's have it be called containsTitle.
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That should be clear, right?
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So again, if we refresh
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Come over here, you'll see that it's now
called title-contains and is looking for
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contains-title as the link.
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Pretty cool, right?
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For more on these powerful search queries,
see the teacher's notes.
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Now, side note here too is that this
rest resource little name that we did,
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on the course repository.
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We can also change this up here.
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So you could change what the default
pluralization of the route.
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Now you can also change the global paging
size with a simple configuration change.
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Let me show you this.
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It's a pretty common
stack overflow request.
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So first remember that spring
boot looks specifically for
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property files in the class path.
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So if we come over here and we make a new
file In the resources root new file and
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we call it application.properties.
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We can set different configuration things.
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So let's say that we find that our
team wants to only show five of these
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courses on a page at a time or
reviews too and
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they keep specifying a different size
in the URL, we don't wanna make them
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do that what we really wanna always have
the default page size to be 5, right?
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So you do
spring.data.rest.default-page-size.
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And now, by default it was 20, right?
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We were seeing 20 on the page.
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What if we say 5?
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So we'll just do equals 5, and
then if we come back over to our
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All right, PI over here.
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If you just look at courses,
you'll see that there are only 5.
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And now it shows that
the last page is page 20.
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There's 20 pages of fun.
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Awesome, right?
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We'll go over a few more of the options
that you can tweak in here and
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I've included the link
in the teacher's notes.
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