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Java 杰克逊'；s json解析

java json

Java 杰克逊'；s json解析,java,json,jackson,jackson2,jackson-databind,Java,Json,Jackson,Jackson2,Jackson Databind,我是一名研究生，正在尝试学习如何使用Jackson解析json到对象 I'm currently trying to parse this { "EmptyMessage":"", "EmptyMessageType":0, "Result":[ { "HasEducationPlan":false, "MembersUrl":"https://student.ulife.com.br/DisciplineMem

我是一名研究生，正在尝试学习如何使用Jackson解析json到对象

I'm currently trying to parse this

        {
   "EmptyMessage":"",
   "EmptyMessageType":0,
   "Result":[
      {
         "HasEducationPlan":false,
         "MembersUrl":"https://student.ulife.com.br/DisciplineMembersList/Index?cd=zzlaAJL5JngfbcsZdA37nw%3d%3d",
         "CalendarUrl":"https://student.ulife.com.br/Calendar?cd=zzlaAJL5JngfbcsZdA37nw%3d%3d",
         "EvaluationUrl":"https://www.ulife.com.br/Student/PAT/Grades.aspx?cd=zzlaAJL5JngfbcsZdA37nw%3d%3d",
         "DiscussionUrl":"https://www.ulife.com.br/Student/PAT/DiscussionForum.aspx?cld=zzlaAJL5JngfbcsZdA37nw%3d%3d",
         "ContentUrl":"https://student.ulife.com.br/Lesson/Index?cd=zzlaAJL5JngfbcsZdA37nw%3d%3d",
         "GradeUrl":"https://student.ulife.com.br/Grade/Index?cd=zzlaAJL5JngfbcsZdA37nw%3d%3d&st=ACFdBAwNYJcCXLzBpH3P2A%3d%3d",
         "CourseUrl":"https://www.ulife.com.br/OrganizationCourse/OrganizationCourseDetail.aspx?o=NaltKyU6OKV8RcmQsxNuow%3d%3d&c=pfRucFwwUMlY%2fZLlwzIjUA%3d%3d",
         "ClassUrl":"/classes/classpage.aspx?ClassId=HxpJ4cUZ4IMKkDlj0kHcGg%3d%3d",
         "PerformanceUrl":null,
         "FrequencyUrl":"/Frequency/ClassDisciplineFrequency.aspx?d=nY1NINmbyIbvqz57uw6Opw%3d%3d&cn=qOJe4AcqjlNHYLakMKbXN9xDtpV0kzjJS%2bcMI7I5%2bEA%3d",
         "DisciplineUrl":"/PAT/Discipline.aspx?p=VowhoBFwb8B%2b9wSJMxKnGVSJJ%2bjEks6OW%2fm%2bxzwPHeg%3d",
         "ChallengeUrl":"https://www.ulife.com.br/Controls/EnadeChallenge.aspx?scd=22405329",
         "ViewMembers":true,
         "NewFeatureEnabled":true,
         "StudentClassDisciplineID":22405329,
         "StudentID":0,
         "ClassDisciplineID":710835,
         "StudentClassDisciplineStatus":1,
         "DisciplineContentID":610112,
         "HasDisciplineContent":true,
         "CurriculumEducationPlanID":0,
         "OrganizationID":2418,
         "DisciplineID":336026,
         "DisciplineName":"Cálculo Diferencial",
         "IsMultiOrganization":false,
         "Enrolled":true,
         "ClassID":586235,
         "ClassName":"MAT2AN-CMA-740642",
         "GradeID":3421,
         "GradeName":"Graduação (Teórica)",
         "OrganizationCourseID":35873,
         "OrganizationCourseName":"Matemática",
         "OriginOrganizationCourseID":0,
         "ModuleStepID":246695,
         "ModuleStepName":"UNIBH_2019/1",
         "ModuleStepStartDate":"2019-01-01T00:00:00",
         "ModuleStepEndDate":"2019-07-31T00:00:00",
         "HasFrequency":false,
         "HasEvaluationPeriod":false,
         "HasEnade":false,
         "StudentActive":true,
         "EnadeChallengeTypeId":0,
         "HasDiscussionForum":false,
         "NewLessonCategoryCount":0,
         "Year":0,
         "DisciplineContentCoverImageUrl":"",
         "LessonCount":2
      },
      {
         "HasEducationPlan":false,
         "MembersUrl":"https://student.ulife.com.br/DisciplineMembersList/Index?cd=0%2fxd%2bn56aFe%2fgp2xBqXe0Q%3d%3d",
         "CalendarUrl":"https://student.ulife.com.br/Calendar?cd=0%2fxd%2bn56aFe%2fgp2xBqXe0Q%3d%3d",
         "EvaluationUrl":"https://www.ulife.com.br/Student/PAT/Grades.aspx?cd=0%2fxd%2bn56aFe%2fgp2xBqXe0Q%3d%3d",
         "DiscussionUrl":"https://www.ulife.com.br/Student/PAT/DiscussionForum.aspx?cld=0%2fxd%2bn56aFe%2fgp2xBqXe0Q%3d%3d",
         "ContentUrl":"https://student.ulife.com.br/Lesson/Index?cd=0%2fxd%2bn56aFe%2fgp2xBqXe0Q%3d%3d",
         "GradeUrl":"https://student.ulife.com.br/Grade/Index?cd=0%2fxd%2bn56aFe%2fgp2xBqXe0Q%3d%3d&st=ACFdBAwNYJcCXLzBpH3P2A%3d%3d",
         "CourseUrl":"https://www.ulife.com.br/OrganizationCourse/OrganizationCourseDetail.aspx?o=NaltKyU6OKV8RcmQsxNuow%3d%3d&c=P56mWzUmVubJFqSYQZZBTA%3d%3d",
         "ClassUrl":"/classes/classpage.aspx?ClassId=ToF93aLWQkJzIIFV0b3mSw%3d%3d",
         "PerformanceUrl":null,
         "FrequencyUrl":"/Frequency/ClassDisciplineFrequency.aspx?d=JYmXKwR4RW0MX%2bR8Kwys%2fQ%3d%3d&cn=w1DRd2w9Q%2fcMoXjZ3pLs6D5hDrzbwNfMwAuvQmPULHM%3d",
         "DisciplineUrl":"/PAT/Discipline.aspx?p=PL8%2f48nLqJNCG%2f99VuSqK3S5kwMhst8pjW83%2fJ673F4%3d",
         "ChallengeUrl":"https://www.ulife.com.br/Controls/EnadeChallenge.aspx?scd=22406703",
         "ViewMembers":true,
         "NewFeatureEnabled":true,
         "StudentClassDisciplineID":22406703,
         "StudentID":0,
         "ClassDisciplineID":711306,
         "StudentClassDisciplineStatus":1,
         "DisciplineContentID":0,
         "HasDisciplineContent":false,
         "CurriculumEducationPlanID":0,
         "OrganizationID":2418,
         "DisciplineID":345469,
         "DisciplineName":"Física - Mecânica da Partícula",
         "IsMultiOrganization":false,
         "Enrolled":false,
         "ClassID":586740,
         "ClassName":"CCP1AN-CMA-740631",
         "GradeID":3421,
         "GradeName":"Graduação (Teórica)",
         "OrganizationCourseID":36597,
         "OrganizationCourseName":"Ciência da Computação",
         "OriginOrganizationCourseID":0,
         "ModuleStepID":246695,
         "ModuleStepName":"UNIBH_2019/1",
         "ModuleStepStartDate":"2019-01-01T00:00:00",
         "ModuleStepEndDate":"2019-07-31T00:00:00",
         "HasFrequency":false,
         "HasEvaluationPeriod":false,
         "HasEnade":false,
         "StudentActive":true,
         "EnadeChallengeTypeId":0,
         "HasDiscussionForum":false,
         "NewLessonCategoryCount":0,
         "Year":0,
         "DisciplineContentCoverImageUrl":"",
         "LessonCount":0
      },
      {
         "HasEducationPlan":false,
         "MembersUrl":"https://student.ulife.com.br/DisciplineMembersList/Index?cd=CNqtVoDvLfuYHUOhGmzOQg%3d%3d",
         "CalendarUrl":"https://student.ulife.com.br/Calendar?cd=CNqtVoDvLfuYHUOhGmzOQg%3d%3d",
         "EvaluationUrl":"https://www.ulife.com.br/Student/PAT/Grades.aspx?cd=CNqtVoDvLfuYHUOhGmzOQg%3d%3d",
         "DiscussionUrl":"https://www.ulife.com.br/Student/PAT/DiscussionForum.aspx?cld=CNqtVoDvLfuYHUOhGmzOQg%3d%3d",
         "ContentUrl":"https://student.ulife.com.br/Lesson/Index?cd=CNqtVoDvLfuYHUOhGmzOQg%3d%3d",
         "GradeUrl":"https://student.ulife.com.br/Grade/Index?cd=CNqtVoDvLfuYHUOhGmzOQg%3d%3d&st=ACFdBAwNYJcCXLzBpH3P2A%3d%3d",
         "CourseUrl":"https://www.ulife.com.br/OrganizationCourse/OrganizationCourseDetail.aspx?o=NaltKyU6OKV8RcmQsxNuow%3d%3d&c=aYIoCh5SkcHin16ztI9Wcw%3d%3d",
         "ClassUrl":"/classes/classpage.aspx?ClassId=V%2bsTc0p2Tb3aFsnKomueEg%3d%3d",
         "PerformanceUrl":null,
         "FrequencyUrl":"/Frequency/ClassDisciplineFrequency.aspx?d=RKhkP9%2fdtqRgJUTsCynP1A%3d%3d&cn=w1DRd2w9Q%2fcMoXjZ3pLs6G8uT7M0JST1CtE5q%2f3qds4%3d",
         "DisciplineUrl":"/PAT/Discipline.aspx?p=RvH7tbqmb2d5Ti%2b34CzYYV44YcyWPZJIZVJggmJ2lug%3d",
         "ChallengeUrl":"https://www.ulife.com.br/Controls/EnadeChallenge.aspx?scd=22399401",
         "ViewMembers":true,
         "NewFeatureEnabled":true,
         "StudentClassDisciplineID":22399401,
         "StudentID":0,
         "ClassDisciplineID":711023,
         "StudentClassDisciplineStatus":1,
         "DisciplineContentID":609052,
         "HasDisciplineContent":true,
         "CurriculumEducationPlanID":0,
         "OrganizationID":2418,
         "DisciplineID":337155,
         "DisciplineName":"Institucional I",
         "IsMultiOrganization":true,
         "Enrolled":true,
         "ClassID":586433,
         "ClassName":"CCP1AN-CMA-740638",
         "GradeID":3401,
         "GradeName":"Graduação",
         "OrganizationCourseID":33548,
         "OrganizationCourseName":"Vinte por cento",
         "OriginOrganizationCourseID":0,
         "ModuleStepID":246829,
         "ModuleStepName":"UNIBH_2019/1",
         "ModuleStepStartDate":"2019-01-01T00:00:00",
         "ModuleStepEndDate":"2019-07-31T00:00:00",
         "HasFrequency":false,
         "HasEvaluationPeriod":false,
         "HasEnade":false,
         "StudentActive":true,
         "EnadeChallengeTypeId":0,
         "HasDiscussionForum":false,
         "NewLessonCategoryCount":23,
         "Year":0,
         "DisciplineContentCoverImageUrl":"",
         "LessonCount":17
      },
      {
         "HasEducationPlan":false,
         "MembersUrl":"https://student.ulife.com.br/DisciplineMembersList/Index?cd=MWRz4NHw1JSCymJKHyvoMQ%3d%3d",
         "CalendarUrl":"https://student.ulife.com.br/Calendar?cd=MWRz4NHw1JSCymJKHyvoMQ%3d%3d",
         "EvaluationUrl":"https://www.ulife.com.br/Student/PAT/Grades.aspx?cd=MWRz4NHw1JSCymJKHyvoMQ%3d%3d",
         "DiscussionUrl":"https://www.ulife.com.br/Student/PAT/DiscussionForum.aspx?cld=MWRz4NHw1JSCymJKHyvoMQ%3d%3d",
         "ContentUrl":"https://student.ulife.com.br/Lesson/Index?cd=MWRz4NHw1JSCymJKHyvoMQ%3d%3d",
         "GradeUrl":"https://student.ulife.com.br/Grade/Index?cd=MWRz4NHw1JSCymJKHyvoMQ%3d%3d&st=ACFdBAwNYJcCXLzBpH3P2A%3d%3d",
         "CourseUrl":"https://www.ulife.com.br/OrganizationCourse/OrganizationCourseDetail.aspx?o=NaltKyU6OKV8RcmQsxNuow%3d%3d&c=P56mWzUmVubJFqSYQZZBTA%3d%3d",
         "ClassUrl":"/classes/classpage.aspx?ClassId=K2fUaz1lIjYVYZWVDbIesw%3d%3d",
         "PerformanceUrl":null,
         "FrequencyUrl":"/Frequency/ClassDisciplineFrequency.aspx?d=psxKtayBeShMNC%2fkhyMDRg%3d%3d&cn=fH8YHJoBctFFuBbe3vjGmPI3JKSMxWHK8TQxvSLpT60%3d",
         "DisciplineUrl":"/PAT/Discipline.aspx?p=4D%2bP9RSBlvW5IEgbTzUVxhIucuZyACIN%2bmIa58PxyT4%3d",
         "ChallengeUrl":"https://www.ulife.com.br/Controls/EnadeChallenge.aspx?scd=22403590",
         "ViewMembers":true,
         "NewFeatureEnabled":true,
         "StudentClassDisciplineID":22403590,
         "StudentID":0,
         "ClassDisciplineID":711473,
         "StudentClassDisciplineStatus":1,
         "DisciplineContentID":611058,
         "HasDisciplineContent":true,
         "CurriculumEducationPlanID":0,
         "OrganizationID":2418,
         "DisciplineID":345470,
         "DisciplineName":"Laboratório de Práticas Integradas 1A",
         "IsMultiOrganization":false,
         "Enrolled":true,
         "ClassID":586925,
         "ClassName":"CCP1AN-CMA1-740670",
         "GradeID":3432,
         "GradeName":"Graduação (Prática)",
         "OrganizationCourseID":36597,
         "OrganizationCourseName":"Ciência da Computação",
         "OriginOrganizationCourseID":0,
         "ModuleStepID":246695,
         "ModuleStepName":"UNIBH_2019/1",
         "ModuleStepStartDate":"2019-01-01T00:00:00",
         "ModuleStepEndDate":"2019-07-31T00:00:00",
         "HasFrequency":false,
         "HasEvaluationPeriod":false,
         "HasEnade":false,
         "StudentActive":true,
         "EnadeChallengeTypeId":0,
         "HasDiscussionForum":false,
         "NewLessonCategoryCount":0,
         "Year":0,
         "DisciplineContentCoverImageUrl":"",
         "LessonCount":2
      },
      {
         "HasEducationPlan":false,
         "MembersUrl":"https://student.ulife.com.br/DisciplineMembersList/Index?cd=TZuLq3PpEtt31xeZ06SGsw%3d%3d",
         "CalendarUrl":"https://student.ulife.com.br/Calendar?cd=TZuLq3PpEtt31xeZ06SGsw%3d%3d",
         "EvaluationUrl":"https://www.ulife.com.br/Student/PAT/Grades.aspx?cd=TZuLq3PpEtt31xeZ06SGsw%3d%3d",
         "DiscussionUrl":"https://www.ulife.com.br/Student/PAT/DiscussionForum.aspx?cld=TZuLq3PpEtt31xeZ06SGsw%3d%3d",
         "ContentUrl":"https://student.ulife.com.br/Lesson/Index?cd=TZuLq3PpEtt31xeZ06SGsw%3d%3d",
         "GradeUrl":"https://student.ulife.com.br/Grade/Index?cd=TZuLq3PpEtt31xeZ06SGsw%3d%3d&st=ACFdBAwNYJcCXLzBpH3P2A%3d%3d",
         "CourseUrl":"https://www.ulife.com.br/OrganizationCourse/OrganizationCourseDetail.aspx?o=NaltKyU6OKV8RcmQsxNuow%3d%3d&c=P56mWzUmVubJFqSYQZZBTA%3d%3d",
         "ClassUrl":"/classes/classpage.aspx?ClassId=4hQOURLROzT45urCqEmG0g%3d%3d",
         "PerformanceUrl":null,
         "FrequencyUrl":"/Frequency/ClassDisciplineFrequency.aspx?d=g%2fod%2bQ9Lh69WQPUqIkHAVA%3d%3d&cn=fH8YHJoBctFFuBbe3vjGmNudp6v634AToqCmBdiwWpY%3d",
         "DisciplineUrl":"/PAT/Discipline.aspx?p=GblZUfavs44hSRDDXEjIoGIn%2b0Yf4zcvALpxLCpX7CQ%3d",
         "ChallengeUrl":"https://www.ulife.com.br/Controls/EnadeChallenge.aspx?scd=22397399",
         "ViewMembers":true,
         "NewFeatureEnabled":true,
         "StudentClassDisciplineID":22397399,
         "StudentID":0,
         "ClassDisciplineID":711475,
         "StudentClassDisciplineStatus":1,
         "DisciplineContentID":609158,
         "HasDisciplineContent":true,
         "CurriculumEducationPlanID":0,
         "OrganizationID":2418,
         "DisciplineID":345325,
         "DisciplineName":"LAI: Identidade, Criatividade e Resolução de Problemas",
         "IsMultiOrganization":false,
         "Enrolled":false,
         "ClassID":586927,
         "ClassName":"CCP1AN-CMA1-740671",
         "GradeID":3432,
         "GradeName":"Graduação (Prática)",
         "OrganizationCourseID":36597,
         "OrganizationCourseName":"Ciência da Computação",
         "OriginOrganizationCourseID":0,
         "ModuleStepID":246695,
         "ModuleStepName":"UNIBH_2019/1",
         "ModuleStepStartDate":"2019-01-01T00:00:00",
         "ModuleStepEndDate":"2019-07-31T00:00:00",
         "HasFrequency":false,
         "HasEvaluationPeriod":false,
         "HasEnade":false,
         "StudentActive":true,
         "EnadeChallengeTypeId":0,
         "HasDiscussionForum":false,
         "NewLessonCategoryCount":3,
         "Year":0,
         "DisciplineContentCoverImageUrl":"",
         "LessonCount":2
      }
   ],
   "Success":true,
   "ErrorMessage":null,
   "ErrorType":0
}
跟这个班

public class Result {
    private String DisciplineName;

    public String getDisciplineName() {
        return DisciplineName;
    }

    public void setDisciplineName(String disciplineName) {
        DisciplineName = disciplineName;
    }

    public Result() {
    }

    public Result(String DisciplineName) {
        this.DisciplineName = DisciplineName;
    }

    @Override
    public String toString() {
        return "Result{" +
                "disciplineName='" + DisciplineName + '\'' +
                '}';
    }
}
这是主要的：

public class Main {
    public static void main(String[] args) {

        Ulife u = new Ulife();

        try {
            ObjectMapper mapper = new ObjectMapper();
           // TypeFactory typeFactory = mapper.getTypeFactory();
            mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
            JsonNode node = mapper.readTree(u.getDisciplinas());
            //node = node.get("Result");
            //System.out.println(node.get("Result").get(0).get("DisciplineName"));
            List<Result> myObjects = Arrays.asList(mapper.readValue(node.toString(), Result[].class));
            //List<Result> myObjects = Arrays.asList(mapper.readValue(node.get("Result").traverse(), Result[].class));;
            //List<Result> someClassList = mapper.readValue(node.traverse(), typeFactory.constructCollectionType(List.class, Result.class));
            //List<Result> list = mapper.treeToValue(node, typeRef);
            System.out.println(myObjects);
           // System.out.println(node.get("DisciplineName").asText());
        }
        catch (Exception e){
            System.out.println(e.getMessage());
        }
    }
}

公共类主{
公共静态void main（字符串[]args）{
Ulife u=新Ulife（）；
试一试{
ObjectMapper mapper=新的ObjectMapper（）；
//TypeFactory=mapper.getTypeFactory（）；
configure（在未知属性上反序列化feature.FAIL，false）；
JsonNode=mapper.readTree（u.GetDistrictas（））；
//node=node.get（“结果”）；
//System.out.println（node.get（“结果”）.get（0.get（“规则名称”））；
List myObjects=Arrays.asList（mapper.readValue（node.toString（），Result[].class））；
//List myObjects=Arrays.asList（mapper.readValue（node.get（“Result”）.traverse（），Result[].class））；；
//List someClassList=mapper.readValue（node.traverse（），typeFactory.constructionCollectionType（List.class，Result.class））；
//List List=mapper.treeToValue（节点，typeRef）；
System.out.println（myObject）；
//System.out.println（node.get（“规程名称”）.asText（））；
}
捕获（例外e）{
System.out.println（e.getMessage（））；
}
}
}
但是，当我打印出对象时，它们会给我所有的空值。。。我错过什么了吗？我不需要结果数组之外的值，但我从StructureName开始简单地了解jacksons是如何工作的，我的计划是在它工作时添加一些其他节点

我尝试了一些我在互联网上看到的其他例子，包括在stackoverflow这里的例子，但我无法让它们中的任何一个起作用

提前感谢。

考虑使用Jackson注释。 另外，学习并遵守JavaBean命名约定

下面是一些示例代码：

@JsonIgnoreProperties(ignoreUnknown = true)
public class Result {
    @JsonProperty
    private String disciplineName;

    public String getDisciplineName() {
        return disciplineName;
    }

    public void setDisciplineName(String newValue) {
        disciplineName = newValue;
    }

    public Result() {
    }

    public Result(String disciplineNameValue) {
        disciplineName = disciplineNameValue;
    }

    @Override
    public String toString() {
        return "Result{" +
                "disciplineName='" + disciplineName + '\'' +
                '}';
    }
}
用某种方法编写代码：

Result result;
ObjectMapper mapper = new ObjectMapper();

result = objectMapper.readValue(u.getDisciplinas(), Result.class);
这假设
u.getDistrictas（）
返回一个字符串

不链接到代码。将代码粘贴到问题中并正确设置格式。JSON的代码是长度，这就是为什么我认为这种方式更容易理解。。。SorryEdit可发布原始代码。您可能需要
@JsonProperty（“字段名称”）
，或。您还应该使用标准的Java变量命名模式，不要更改变量以匹配Json值。@谢谢您的故事讲述者。我稍微修改了代码，还添加了您建议我的注释。它现在起作用了。谢谢