In this lesson, we are going to write the GET methods to get list of items. So we would write methods to return list of users. Then we would write method to return list of Posts. Finally, we write method to return list of Locations.<\/p>\n
We’ll cover the following:<\/p>\n
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So we would first write a GET method. This method would just return a string “Welcome to Spring Boot” when the someone accesses \/welcome. To do this, create a new class and name it welcomeController.<\/p>\n
Inside this file write a function that write\u00a0 function welcome() that returns a string “Welcome to Spring Boot”<\/p>\n
Annotate the class with @RestConroller annotation<\/p>\n
Annotate the function with @RestMapping annotation<\/p>\n
If you have done everything right, the content of you welcomeController file would be as shown below.<\/p>\n
<\/p>\n
package<\/span> com.<\/span>kindsonthegenius<\/span>.<\/span>social<\/span>;<\/span>\r\n\r\nimport<\/span> org.springframework.web.bind.annotation.RequestMapping<\/span>;<\/span>\r\nimport<\/span> org.springframework.web.bind.annotation.RestController<\/span>;<\/span>\r\n\r\n@RestController<\/span>\r\npublic<\/span> class<\/span> welcomeController<\/span> {<\/span>\r\n\t\r\n\t@RequestMapping<\/span>(<\/span>value=<\/span>\"\/welcome\"<\/span>)<\/span>\r\n\tpublic<\/span> static<\/span> String welcome<\/span>()<\/span> {<\/span>\r\n\t\treturn<\/span> \"Welcome to Spring Boot\"<\/span>;<\/span>\r\n\t}<\/span>\r\n\t\r\n}<\/span>\r\n<\/pre>\nListing 1.0: Content of the welcomeController.java<\/p>\n
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Now you can start the application. Then open the browser and enter http:\/\/localhost:8080\/welcome<\/p>\n
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2. Write the Method to return List of Users<\/strong><\/h4>\nHere we will write the function that would return list of all the users in our SocialAPI.<\/p>\n
Open the UserController file you created in the previous tutorial. Inside this file you will do the following things:<\/p>\n
create a function and name if getAllUsers()<\/p>\n
annotate this function with @RestMapping annotation<\/p>\n
inside this function create a hard-coded list of users<\/p>\n
<\/p>\n
package<\/span> com.<\/span>kindsonthegenius<\/span>.<\/span>social<\/span>.<\/span>user<\/span>;<\/span>\r\n\r\nimport<\/span> java.util.Arrays<\/span>;<\/span>\r\nimport<\/span> java.util.List<\/span>;<\/span>\r\n\r\nimport<\/span> org.springframework.web.bind.annotation.RequestMapping<\/span>;<\/span>\r\nimport<\/span> org.springframework.web.bind.annotation.RestController<\/span>;<\/span>\r\n\r\nimport<\/span> com.kindsonthegenius.social.location.Location<\/span>;<\/span>\r\n\r\n@RestController<\/span>\r\npublic<\/span> class<\/span> userController<\/span> {<\/span>\r\n\t\r\n @RequestMapping<\/span>(<\/span>value=<\/span>\"\/users\"<\/span>)<\/span>\r\n public<\/span> List<<\/span>User><\/span> getAllUsers<\/span>()<\/span> {<\/span>\r\n\tUser user1 =<\/span> new<\/span> User(<\/span>\r\n\t\t\"u1\"<\/span>,<\/span> \r\n\t\t\"Jany\"<\/span>,<\/span> \r\n\t\t\"Lawrence\"<\/span>,<\/span>\r\n\t\tnew<\/span> Location<\/span>(<\/span>\"l1\"<\/span>,<\/span> \"Lagos\"<\/span>),<\/span>\r\n\t\t\"Jany@gmail.com\"<\/span>);<\/span>\r\n\t\t\r\n\tUser user2 =<\/span> new<\/span> User(<\/span>\r\n\t\t\"u2\"<\/span>,<\/span> \r\n\t\t\"Jadon\"<\/span>,<\/span> \r\n\t\t\"Mills\"<\/span>,<\/span>\r\n\t\tnew<\/span> Location<\/span>(<\/span>\"l2\"<\/span>,<\/span> \"Asaba\"<\/span>),<\/span>\r\n\t\t\"Jadon@gmail.com\"<\/span>);<\/span>\r\n\t\t\r\n\treturn<\/span> Arrays.<\/span>asList<\/span>(<\/span>user1,<\/span> user2);<\/span>\t\r\n\t\r\n }<\/span>\r\n}<\/span>\r\n<\/pre>\nListing 1.1: Content of the userController.java file<\/p>\n
<\/p>\n
Now you can test the application.<\/p>\n
Right-click on the project and Run As SpringBoot Application. Then go to the broser and access http:\/\/localhost:8080\/users. You will get a list of users.<\/p>\n
If not let me know in the comment box below.<\/p>\n
<\/p>\n
3. Write the Method to return List of Posts<\/strong><\/h4>\nHere we will write the function that would return list of all the posts in our SocialAPI.<\/p>\n
Open the PostController file you created in the previous tutorial. Inside this file you will do the following things:<\/p>\n
create a function and name if getAllPosts()<\/p>\n
annotate this function with @RestMapping annotation. See the video<\/p>\n
inside this function create a hard-coded list of posts<\/p>\n
<\/p>\n
package<\/span> com.<\/span>kindsonthegenius<\/span>.<\/span>social<\/span>.<\/span>post<\/span>;<\/span>\r\n\r\nimport<\/span> java.util.Arrays<\/span>;<\/span>\r\nimport<\/span> java.util.List<\/span>;<\/span>\r\n\r\nimport<\/span> org.springframework.web.bind.annotation.RequestMapping<\/span>;<\/span>\r\nimport<\/span> org.springframework.web.bind.annotation.RestController<\/span>;<\/span>\r\n\r\nimport<\/span> com.kindsonthegenius.social.location.Location<\/span>;<\/span>\r\nimport<\/span> com.kindsonthegenius.social.user.User<\/span>;<\/span>\r\n\r\n@RestController<\/span>\r\npublic<\/span> class<\/span> PostController<\/span> {<\/span>\r\n\t\r\n @RequestMapping<\/span>(<\/span>value =<\/span> \"\/posts\"<\/span>)<\/span>\r\n public<\/span> List<<\/span>Post><\/span> getAllPosts<\/span>()<\/span> {<\/span>\r\n\t\t\r\n\tUser user1 =<\/span> new<\/span> User(<\/span>\r\n\t\t\"u1\"<\/span>,<\/span> \r\n\t\t\"Jany\"<\/span>,<\/span> \r\n\t\t\"Lawrence\"<\/span>,<\/span>\r\n\t\tnew<\/span> Location<\/span>(<\/span>\"l1\"<\/span>,<\/span> \"Lagos\"<\/span>),<\/span>\r\n\t\t\"Jany@gmail.com\"<\/span>);<\/span>\r\n\t\t\r\n\tUser user2 =<\/span> new<\/span> User(<\/span>\r\n\t\t\"u2\"<\/span>,<\/span> \r\n\t\t\"Jadon\"<\/span>,<\/span> \r\n\t\t\"Mills\"<\/span>,<\/span>\r\n\t\tnew<\/span> Location<\/span>(<\/span>\"l2\"<\/span>,<\/span> \"Asaba\"<\/span>),<\/span>\r\n\t\t\"Jadon@gmail.com\"<\/span>);<\/span>\r\n\t\t\r\n\tPost post1 =<\/span> new<\/span> Post(<\/span>\r\n\t\t\"p1\"<\/span>,<\/span>\r\n\t\t\"01-Jan-19\"<\/span>,<\/span>\r\n\t\tuser1,<\/span>\r\n\t \"Its good to love and be loved\"<\/span>);<\/span>\r\n\t\t\r\n\tPost post2 =<\/span> new<\/span> Post(<\/span>\r\n\t\t\"p2\"<\/span>,<\/span>\r\n\t \"02-Jan-19\"<\/span>,<\/span>\r\n\t\tuser2,<\/span>\r\n\t\t\"We all need someone\"<\/span>);<\/span>\t\t\r\n\t\t\r\n\treturn<\/span> Arrays.<\/span>asList<\/span>(<\/span>post1,<\/span> post2);<\/span>\r\n \r\n }<\/span>\r\n}<\/span>\r\n<\/pre>\nListing 1.2: Content of the postController.java file<\/p>\n
<\/p>\n
Now you can test the getAllPosts method.<\/p>\n
Right-click on the project and Run As SpringBoot Application. Then go to the browser and access http:\/\/localhost:8080\/posts. You will get a list of posts.<\/p>\n
If not let me know in the comment box below.<\/p>\n
<\/p>\n
4. Write the Method to return List of Locations<\/strong><\/h4>\nHere we will write the function that would return list of all the posts in our SocialAPI. This would be easier than the previous two.<\/p>\n
Open the LocationController file you created in the previous tutorial. Inside this file you will do the following things:<\/p>\n
create a function and name if getAllLocations()<\/p>\n
annotate this function with @RestMapping annotation. See the video<\/p>\n
inside this function create a hard-coded list of locations<\/p>\n
<\/p>\n
import<\/span> java.util.Arrays<\/span>;<\/span>\r\nimport<\/span> java.util.List<\/span>;<\/span>\r\n\r\nimport<\/span> org.springframework.web.bind.annotation.RequestMapping<\/span>;<\/span>\r\nimport<\/span> org.springframework.web.bind.annotation.RestController<\/span>;<\/span>\r\n\r\n