如何在 Java REST API 中向 GetMapping 添加逻辑

Question

I am trying to implement a very simple REST API with Spring Boot. In a GET Request I want to do a very basic transliteration. So the requestor will have to send an input string and transliteration string.

Those parameters should be passed to my method, that returns a transliteration. The Response should look like this:

"input": ...
"transliterationrule": ...
"transliteration": ...

To do so, I created a java spring boot project with the following classes:

1. Transliteration class

    import com.ibm.icu.text.Transliterator;

   public class Transliteration {

    private final String input; private final String transliterationRule; public Transliteration(String input, String transliterationRule) { this.input = input; this.transliterationRule = transliterationRule; } public String transliterateString(){ Transliterator transliterator = Transliterator.getInstance(this.transliterationRule); return transliterator.transliterate(this.input); } public String getInput(){ return input; } public String getTransliterationRule(){ return transliterationRule; }

   }

And controller class:

@RestController
public class TransliterationController {

    @GetMapping("/transliteration")
    public Transliteration transliteration(@RequestParam(value="input", required=false, defaultValue="TestString") String input,
    @RequestParam(value="rule", required=false, defaultValue="Any-Latin") String transliterationRule) {
        return new Transliteration(input, transliterationRule);
    }

}

Can somebody please explain me, how I can actually pass these parameters to my method transliterateString()? And how can I add the method result do the request?

Answer 1

Change your controller's method to return ResponseEntity and wrap a TransliterationResponse. TransliterationResponse is a dto holding "input": ... "transliterationrule": ... "transliteration": ...

    @GetMapping("/transliteration")
public ResponseEntity<TransliterationResponse> transliteration(@RequestParam(value="input", required=false, defaultValue="TestString") String input,
@RequestParam(value="rule", required=false, defaultValue="Any-Latin") String transliterationRule) {
    // do your business logic
    //build the response dto
    TransliterationResponse dto = new TransliterationResponse(input, transliterationrule, transliteration);
    ResponseEntity.status(HttpStatus.OK).body(dto);
}

Answer 2

Create a DTO class to contain all response values:

public class TransliterationDTO {    
    @JsonProperty("input")
    private String input;
    @JsonProperty("transliterationRule")
    private String transliterationRule;
    @JsonProperty("transliteration")
    private String transliteration;

    public TransliterationDTO() {
    }

    public TransliterationDTO(String input, String transliterationRule, String transliteration) {
        this.input = input;
        this.transliterationRule = transliterationRule;
        this.transliteration = transliteration;
    }

    // Getters and Setters
}

Update your controller method to return a ResponseEntity:

@RestController
public class TransliterationController {

    @GetMapping("/transliteration")
    public ResponseEntity<TransliterationDTO> transliteration(@RequestParam(value="input", required=false, defaultValue="TestString") String input,
                                           @RequestParam(value="rule", required=false, defaultValue="Any-Latin") String transliterationRule) {
        Transliteration t = new Transliteration(input, transliterationRule);
        return ResponseEntity.ok(new TransliterationDTO(t.getInput(), t.getTransliterationRule(), t.getTransliteration));
    }
}