SpringBoot error when creating Api Rest

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SpringBoot error when creating Api Rest

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#1 by (4 votes)

1

I'm learning how to use SpringBoot and I can not make it work with the classes I created, I'll leave the code in case you can help or pass some link from a tutorial or video that explains it in a simple way the use of the framework.

import org.springframework.web.bind.annotation.*;

import java.util.concurrent.atomic.AtomicLong;

@RestController
public class CorreoController {
    private final AtomicLong counter = new AtomicLong();

    @RequestMapping(value = "/correo/nuevo",method = RequestMethod.GET)
    @ResponseBody
    public String correo (@PathVariable(value = "from") String from, 
    @PathVariable(value = "to") String to, @PathVariable(value = 
    "asunto")String asunto, @PathVariable(value = "texto") String texto){
        Correo correito = new Correo(from,to,asunto,texto);
        return correito.toString();
    }

java spring-boot

asked by Maxi Hernandez 23.11.2017 в 12:03

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1 answer

I put the fields in minuscule but Error 1215 still appears. Can not add foreign key constraint Configuration TomCat Netbeans Local

score 4 · Accepted Answer

We will assume that we already have the previous configuration of the project done and we have added the web dependencies within our pom.xml.

Imagine that we want to create an endpoint following a rest architecture so we have defined that the name of our resource is coffee and we are doing a GET operation to bring data about this resource, the endpoint would be the following:

www.miurlfavorita.com/coffee/{id}

where {id} is a number that identifies our resource and comes to be the same as spring maps on our @PathVariable tag. To perform this mapping correctly, in our controller we define the method that generates the endpoint:

@ResponseBody
@GetMapping(produces = [MediaType.APPLICATION_JSON_UTF8_VALUE], value = '/{idCoffee}')
CoffeeResponse getCoffeeInfo(
    @PathVariable('idCoffee') String idCoffee
) {
//Lógica que hace lo que sea
}

Let's analyze this method for a moment, if you look at the code you've shared, you use the @PathVariable tag but in your @RequestMapping you do not indicate inside the endpoint where those variables are so Spring does not know where they come from . If you look at the method I use the @GetMapping tag that does the same as @RequestMapping but by default the http method is already get what is much more readable and I recommend its use (there are also @PostMapping , @PutMapping ... etc).

Within @getMApping you can see that I have the {idCoffee} between braces what tells Spring that in this part of the url what is coming is not the literal "idCoffee", it comes a "variable path" that has to map in the corresponding parameter.

Finally, within the url that I have defined, where do I indicate to Spring the / coffee that indicates the name of the resource? This is indicated in the class and not in the method since it is not a good practice. Ideally, each controller should refer to a particular resource and all the methods should be different operations on it, so my class would be defined as such.

@RequestMapping(value = '/coffee')
@RestController
class BestCoffeeClassEver {
...    
}

In this case I use the @RequestMapping without any type of operation since I am at the class level so all the endpoints that I generate in that class will be url / coffee / (whichever it generates in each method).