java - 使用 Spring Web 服务时的 Enum 类型转换

Question

这将是以下问题的延伸:

Spring web service request and response for mapping having list of other objects

如果问题 POJO 有枚举类型怎么办？当发出请求并使用 @RequestBody 时，如何在 ajax 调用中表示这一点。

例如:

public class Question {

    private String questionText;

    List<Options> options;

    private QuestionTye questionType

    public String getQuestionText() {
        return questionText;
    }

    public void setQuestionText(String questionText) {
        this.questionText = questionText;
    }

    //getters and setters for options


}

枚举如下所示:

public enum QuestionType {

    MCQ, FILL_IN_THE_BLANK, QUESTION_AND_ANSWER, MATCH_THE_FOLLOWING

}

将 JSON 发送到服务器时应如何格式化它？

Answer 1

假设您的类补丁上有 jackson API，请添加带注释的“Create”方法。我还喜欢在枚举中添加“None”选项以避免空指针:

public enum QuestionType {

    MCQ, FILL_IN_THE_BLANK, QUESTION_AND_ANSWER, MATCH_THE_FOLLOWING, NONE;

    @JsonCreator
    public QuestionType create(String input){

        QuestionType result;
        if("MCQ".equals(input)){

            result = MCQ;
        }
        else if(/*snip etc*/){

        }//etc
        else{

           result = NONE;//Or null or throw an exception .. whatever
        }
        return result;
    }
}