In this chapter, we are going to add JPA repositories to our Social API.<\/p>\n
In the previous chapter, you learnt about JPA repositories. You also learn how to add it to the application.<\/p>\n
You can review them:Create JPA Repository<\/a> and Crud Operations with JPS Repository<\/a>.<\/p>\n <\/p>\n We would cover the following:<\/p>\n <\/p>\n To be able to use repository you need to make some changes to the classes. Open each class and do the following<\/p>\n First<\/strong>, annotate the class with @Entity annotation<\/p>\n Second<\/strong>, annotate the id with @Id annotation (this sets it as primary key)<\/p>\n Third<\/strong>, add an empty constructor (constructor with no parameters)<\/p>\n If you miss something, then watch the video to see how to do it.<\/p>\n <\/p>\n <\/p>\n So you need to add JPA repositories for Location, Users and Posts. Follow the same method as you did in the previous chapter for adding JPA repository for the Student class.<\/p>\n Just create\u00a0 an interface in the same package and name it accordingly.<\/p>\n For example the LocationRepository is given below:<\/p>\n <\/p>\n <\/p>\n <\/p>\n So repeat the same for the User and Post classes.<\/p>\n <\/p>\n <\/p>\n Now you need to open the LocationService class. Delete all the methods inside and replace with the code similar to that in StudentService. At the end, the content of LocationService would be as shown below:<\/p>\n <\/p>\n <\/p>\n <\/p>\n If you get it correctly, then the UserService would\u00a0 be as shown below:<\/p>\n <\/p>\n <\/p>\n <\/p>\n For the PostService,\u00a0 we would have the content as below:<\/p>\n <\/p>\n\n
1. Modify the Classes<\/strong><\/h4>\n
2. Add the JPA Repositories<\/strong><\/h4>\n
package<\/span> com.<\/span>kindsonthegenius<\/span>.<\/span>social<\/span>.<\/span>location<\/span>;<\/span>\r\nimport<\/span> org.springframework.data.repository.CrudRepository<\/span>;<\/span>\r\n\r\npublic<\/span> interface<\/span> LocationRepository<\/span> extends<\/span> CrudRepository<<\/span>Location,<\/span> String><\/span> {<\/span>\r\n\t\r\n}<\/span>\r\n<\/pre>\n3. Add Crud Operations for LocationService<\/strong><\/h4>\n
@Service<\/span>\r\npublic<\/span> class<\/span> StudentService<\/span> {<\/span>\r\n\t\r\n\t@Autowired<\/span>\r\n\tpublic<\/span> StudentRepository studentRepository;<\/span>\r\n\t\r\n\tpublic<\/span> List<<\/span>Student><\/span> getAllStudents<\/span>()<\/span> {<\/span>\r\n\t\t\r\n\t\tList<<\/span>Student><\/span> students =<\/span> new<\/span> ArrayList<>();<\/span>\r\n\t\t\r\n\t\tstudentRepository.<\/span>findAll<\/span>()<\/span>\r\n\t\t.<\/span>forEach<\/span>(<\/span>students:<\/span>:<\/span>add);<\/span>\r\n\t\t\r\n\t\treturn<\/span> students;<\/span>\t\t\r\n\t}<\/span>\r\n\t\t\r\n\tpublic<\/span> void<\/span> addStudent<\/span>(<\/span>Student student)<\/span> {<\/span>\r\n\t\tstudentRepository.<\/span>save<\/span>(<\/span>student);<\/span>\r\n\t}<\/span>\r\n\t\t\r\n\tpublic<\/span> Optional<<\/span>Student><\/span> getStudent<\/span>(<\/span>String id)<\/span> {<\/span>\r\n\t\treturn<\/span> studentRepository.<\/span>findById<\/span>(<\/span>id);<\/span>\r\n\t}<\/span>\r\n\t\r\n\tpublic<\/span> void<\/span> deleteStudent<\/span>(<\/span>String id)<\/span> {<\/span>\r\n\t\tstudentRepository.<\/span>deleteById<\/span>(<\/span>id);<\/span>\r\n\t}<\/span>\r\n\t\r\n\tpublic<\/span> void<\/span> updateStudent<\/span>(<\/span>String id,<\/span> Student student)<\/span> {<\/span>\r\n\t studentRepository.<\/span>save<\/span>(<\/span>student);<\/span>\r\n\t}<\/span>\r\n}<\/span>\r\n<\/pre>\n4. Add Crud Operations for UserService<\/strong><\/h4>\n
@Service<\/span>\r\npublic<\/span> class<\/span> UserService<\/span> {<\/span>\r\n\t\r\n\t@Autowired<\/span>\r\n\tprivate<\/span> UserRepository userRepository;<\/span>\t\r\n\t\r\n\tpublic<\/span> List<<\/span>User><\/span> getAllUsers<\/span>()<\/span> {<\/span>\r\n\t\tList<<\/span>User><\/span> users =<\/span> new<\/span> ArrayList<>();<\/span>\r\n\t\t\r\n\t\tuserRepository.<\/span>findAll<\/span>()<\/span>\r\n\t\t.<\/span>forEach<\/span>(<\/span>users:<\/span>:<\/span>add);<\/span>\r\n\t\t\r\n\t\treturn<\/span> users;<\/span>\r\n\t}<\/span>\r\n\t\t\r\n\tpublic<\/span> Optional<<\/span>User><\/span> getUser<\/span>(<\/span>String id)<\/span> {<\/span>\r\n\t\treturn<\/span> userRepository.<\/span>findById<\/span>(<\/span>id);<\/span>\r\n\t}<\/span>\r\n\r\n\tpublic<\/span> void<\/span> addUser<\/span>(<\/span>User user)<\/span> {<\/span>\r\n\t\tuserRepository.<\/span>save<\/span>(<\/span>user);<\/span>\r\n\t}<\/span>\r\n\r\n\tpublic<\/span> void<\/span> updateUser<\/span>(<\/span>String id,<\/span> User user)<\/span> {<\/span>\r\n\t\tuserRepository.<\/span>save<\/span>(<\/span>user);<\/span>\r\n\t}<\/span>\r\n\t\r\n\tpublic<\/span> void<\/span> deleteUser<\/span>(<\/span>String id)<\/span> {<\/span>\r\n\t userRepository.<\/span>deleteById<\/span>(<\/span>id);<\/span>\t\r\n\t}<\/span>\r\n}<\/span>\r\n<\/pre>\n5. Add Crud Operations for PostService<\/strong><\/h4>\n
@Service<\/span>\r\npublic<\/span> class<\/span> PostService<\/span> {<\/span>\r\n\t\t\r\n\tprivate<\/span> PostRepository postRepository;<\/span>\r\n\t\r\n\tpublic<\/span> List<<\/span>Post><\/span> getAllPosts<\/span>()<\/span> {<\/span>\r\n\t List<<\/span>Post><\/span> posts =<\/span> new<\/span> ArrayList<>();<\/span>\r\n\t \r\n\t postRepository.<\/span>findAll<\/span>()<\/span>\r\n\t .<\/span>forEach<\/span>(<\/span>posts:<\/span>:<\/span>add);<\/span>\r\n\t \r\n\t return<\/span> posts;<\/span>\t \r\n\t}<\/span>\r\n\t \t \r\n\tpublic<\/span> Optional<<\/span>Post><\/span> getPost<\/span>(<\/span>String id)<\/span> {<\/span>\r\n\t\treturn<\/span> postRepository.<\/span>findById<\/span>(<\/span>id