从json文件生成java类

Question

我已使用在线转换器http://pojo.sodhanalibrary.com/将answer.json转换为java类。我在json中有硬编码的值，但是当我尝试使用AnswerTest.java访问这些值时，我正在关注＆＃34; OUTPUT＆＃34;：

ClassPojo [Section_Name = null, Answers = null, User_Id = null, Form_Name = null, Answers1 = null]

为什么我得到空值？

answer.json

{ 
"User_Id": "abcd",
"Form_Name": "Form",
"Answers": [{
                        "Question_Id": "1",
                        "Answer" :"a"
                                        },
                                        {
                        "Question_Id": "2",
                        "Answer" :"b"
                                        },
                                        {
                        "Question_Id": "3",
                        "Answer" :"c"
                                        }
                        ],
"Section_Name": "Project Overview",
"Answers1": [{
                        "Question_Id": "4",
                        "Answer" :"d"
                                        },
                                        {
                        "Question_Id": "5",
                        "Answer" :"e"
                                        },
                                        {
                        "Question_Id": "6",
                        "Answer" :"f"
                                        }
                        ]                             

}

这些是为上面的json生成的类：

Answer.java

public class Answer
{
private String Section_Name;

private Answers[] Answers;

private String User_Id;

private String Form_Name;

private Answers1[] Answers1;

public String getSection_Name ()
{
    return Section_Name;
}

public void setSection_Name (String Section_Name)
{
    this.Section_Name = Section_Name;
}

public Answers[] getAnswers ()
{
    return Answers;
}

public void setAnswers (Answers[] Answers)
{
    this.Answers = Answers;
}

public String getUser_Id ()
{
    return User_Id;
}

public void setUser_Id (String User_Id)
{
    this.User_Id = User_Id;
}

public String getForm_Name ()
{
    return Form_Name;
}

public void setForm_Name (String Form_Name)
{
    this.Form_Name = Form_Name;
}

public Answers1[] getAnswers1 ()
{
    return Answers1;
}

public void setAnswers1 (Answers1[] Answers1)
{
    this.Answers1 = Answers1;
}

@Override
public String toString()
{
    return "ClassPojo [Section_Name = "+Section_Name+", Answers =  "+Answers+", User_Id = "+User_Id+", Form_Name = "+Form_Name+", Answers1 =  "+Answers1+"]";
 }
}

Answers.java

public class Answers
{
private String Question_Id;

private String Answer;

public String getQuestion_Id ()
{
    return Question_Id;
}

public void setQuestion_Id (String Question_Id)
{
    this.Question_Id = Question_Id;
}

public String getAnswer ()
{
    return Answer;
}

public void setAnswer (String Answer)
{
    this.Answer = Answer;
}

@Override
public String toString()
{
    return "ClassPojo [Question_Id = "+Question_Id+", Answer = "+Answer+"]";
}
}

Answers1.java

public class Answers1
{
private String Question_Id;

private String Answer;

public String getQuestion_Id ()
{
    return Question_Id;
}

public void setQuestion_Id (String Question_Id)
{
    this.Question_Id = Question_Id;
}

public String getAnswer ()
{
    return Answer;
}

public void setAnswer (String Answer)
{
    this.Answer = Answer;
}

@Override
public String toString()
{
    return "ClassPojo [Question_Id = "+Question_Id+", Answer = "+Answer+"]";
}
}

AnswerTest.java

这是我从json打印数据的测试类。

public class AnswerTest {

public static void main(String[] args) throws JsonParseException,
        JsonMappingException, IOException {

    try {
        File jsonFile = new File("answer.json");
        Answer answer = null;

        ObjectMapper objectMapper = new ObjectMapper();

        objectMapper.configure(
                DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        answer = objectMapper.readValue(jsonFile, Answer.class);
        System.out.println(answer);
            }

    catch (Exception e) {

        e.printStackTrace();

    }
}
}