Lab

APIs respond with JSON representations of data.

Including the Jackson jars, which we discussed earlier, automatically maps returned Java objects to json or primitive types to a string representation.

1. Open the project we configured with ping/pong, MyFirstRestProject.

2. Create a package called com.example.rest.data.

3. Create a User class.
4. A User should have a name, username, email, and password.
5. Create all the appropriate getters and setters for these fields.
6. Create a constructor that takes these 4 values, as well as a no-arg.

7. Generate a toString.

8. The Jackson Library uses these gets and sets to generate the json, so if they aren't included, your program will fail.

9. In the controller create another method getUser(). Assign the URL /users path to this method using @RequestMapping. Inside of the methods, instantiate a new instance of a User and return the created object. (Your instance will use hardcoded data, like the example below.)

@GetMapping("api/users/1")
public User getUser(){
  return new User("Julia Cousins", "JCousins", "JC@gmail.com", "wombat1");
}

1. Using Postman, hit the URL http://localhost:8080/api/users/1. You should get the json representation of the User object as a response. If you are getting errors make sure you have properly included all gets and sets in the User class.

{
  "name":"Julia Cousins",
  "username" : "JCousins",
  "email":"JC@gmail.com",
  "password":"wombat1"
}

1. Add a post method in the controller:

@PostMapping("api/users")
public String addUser(@RequestBody String userParam){
  System.out.println(userParam);
  return userParam;
}

1. Create a test request in Postman with the method POST, URL http://localhost:8080/api/users, and a *Body with type raw and application/json. Enter a JSON request body:

{
  "name": "Froderick Fronkensteen",
  "username": "froderick",
  "email": "FF@gmail.com",
  "password": "tapdance"
}

Send the request, and observe the response in Postman as well as the console output from Spring.

1. Change the parameter type and the return type from String to User:

@PostMapping("api/users")
public User addUser(@RequestBody User userParam){
  System.out.println(userParam);
  return userParam;
}

Send the request, and observe the response in Postman as well as the console output from Spring.

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