使用 Xstream 反序列化 JSON 对象

问题描述 投票:0回答:0

我的任务是描述学生和学术组的课程(带有字段 - 一组学生)。创建对象。使用三种方法提供文件创建和读取文件:

JSON 中的序列化和反序列化(通过 XStream)。

我序列化了一个有学生数组列表的学术组:


public class AcademicGroup  {

    private List<Student> students;

    public AcademicGroup() {
        this.students = new ArrayList<>();
    }

    public void addStudent(Student student) {
        students.add(student);
    }

    public Student[] getStudents() {
        return students.toArray(new Student[0]);
    }
}

和学生:



public class Student {
    private String name;
    private String group;

    public Student(String name, String group) {
        this.name = name;
        this.group = group;
    }

    public String getName() {
        return name;
    }

    public String getGroup() {
        return group;
    }

    @Override
    public String toString() {
        return name + " " + group;
    }
}

序列化功能

public static void studentJsonSerialization() {
        XStream xStream = new XStream(new JsonHierarchicalStreamDriver());
        List<Student> students = Arrays.asList(
                new Student("Student1", "KN-221A"),
                new Student("Student2", "KN-221A"),
                new Student("Student3", "KN-221A")
        );
        AcademicGroup academicGroup = new AcademicGroup();
        for (Student student : students) {
            academicGroup.addStudent(student);
        }
        xStream.alias("academicGroup", AcademicGroup.class);
        String xml = xStream.toXML(academicGroup);
        try (FileWriter fw = new FileWriter("AcademicGroup.json");
             PrintWriter out = new PrintWriter(fw)) {
            out.println(xml);
        }
        catch (IOException e) {
            e.printStackTrace();
        }
}

我得到的文件 AcademicGroup.json:

{"academicGroup": {
  "students": [
    {
      "name": "Student1",
      "group": "KN-221A"
    },
    {
      "name": "Student2",
      "group": "KN-221A"
    },
    {
      "name": "Student3",
      "group": "KN-221A"
    }
  ]
}}

反序列化函数:

    public static void studentJsonDeserialization() {
        XStream xStream = new XStream(new JettisonMappedXmlDriver());
        xStream.addPermission(AnyTypePermission.ANY);
        xStream.alias("academicGroup", AcademicGroup.class);

        AcademicGroup newAcademicGroup = (AcademicGroup) xStream.fromXML(new File("AcademicGroup.json"));
        for (Student student : newAcademicGroup.getStudents()) {
            System.out.println(student.toString());
        }
    }

我需要在控制台中打印 json 对象,但我收到一条错误消息

Exception in thread "main" com.thoughtworks.xstream.converters.ConversionException: 
---- Debugging information ----
cause-exception     : com.thoughtworks.xstream.mapper.CannotResolveClassException
cause-message       : name
class               : java.util.ArrayList
required-type       : java.util.ArrayList
converter-type      : com.thoughtworks.xstream.converters.collections.CollectionConverter
path                : /academicGroup/students/name
line number         : -1
class[1]            : org.example.AcademicGroup
required-type[1]    : org.example.AcademicGroup
converter-type[1]   : com.thoughtworks.xstream.converters.reflection.ReflectionConverter
version             : 1.4.20
java json deserialization xstream
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