Spring Boot 2 REST API

REST API Controller

  • In Spring, a controller class, which is capable of serving REST API requests, is called rest controller. It should be annotated with @RestController annotation.

  • The resource uris are specified in @RequestMapping annotations. It can be applied at class level and method level both. Complete URI for an API is resolved after adding class level path and method level path.

  • We should always write produces and consumes attributes to specify the mediatype attributes for the API. Never reply on assumptions.

HTTP GET /employees

http://localhost:18090/employees/

HTTP POST /employees

http://localhost:18090/employees/

{
	"firstName": "T5750",
	"lastName": "T5750",
	"email": "T5750@gmail.com"
}

Exception handling

Results

  1. HTTP GET /employees/vo/1 [VALID]

  2. HTTP GET /employees/vo/23 [INVALID]

  3. HTTP POST /employees/vo [INVALID]

    {
	"lastName": "T5750",
	"email": "T5750@gmail.com"
}

  4. HTTP POST /employees/vo [INVALID]

    {
	"email": "T5750@gmail.com"
}

  5. HTTP POST /employees/vo [INVALID]

    {
	"firstName": "T5750",
	"email": "T5750_gmail.com" //invalid email in request
}

REST request validation annotations

ANNOTATION USAGE
@AssertFalse The annotated element must be false.
@AssertTrue The annotated element must be true.
@DecimalMax The annotated element must be a number whose value must be lower or equal to the specified maximum.
@DecimalMin The annotated element must be a number whose value must be higher or equal to the specified minimum.
@Future The annotated element must be an instant, date or time in the future.
@Max The annotated element must be a number whose value must be lower or equal to the specified maximum.
@Min The annotated element must be a number whose value must be higher or equal to the specified minimum.
@Negative The annotated element must be a strictly negative number.
@NotBlank The annotated element must not be null and must contain at least one non-whitespace character.
@NotEmpty The annotated element must not be null nor empty.
@NotNull The annotated element must not be null.
@Null The annotated element must be null.
@Pattern The annotated CharSequence must match the specified regular expression.
@Positive The annotated element must be a strictly positive number.
@Size The annotated element size must be between the specified boundaries (included).

References