从 Firebase 数据结构映射到 JAVA 对象时出现无法识别的字段答案

【问题标题】：Unrecognized field when mapping from Firebase data structure to JAVA object从 Firebase 数据结构映射到 JAVA 对象时出现无法识别的字段
【发布时间】：2016-08-09 18:00:10
【问题描述】：

这是我试图映射到 JAVA 对象的数据结构，但我不知道如何正确映射 groupId 属性。有人可以告诉我它是如何完成的吗？ [

    Caused by: java.lang.IllegalArgumentException: Unrecognized field "1" (class firebasetest.model.GroupWithGroupId), not marked as ignorable (6 known properties: , "lastGroupId", "hourLimit", "maxLimit", "minLimit", "groupId", "actualLimit"])
    08-09 19:04:43.130 8259-8259/firebasetest I/System.out:     at [Source: N/A; line: -1, column: -1] (through reference chain: firebasetest.model.GroupWithGroupId["1"])
08-09 19:04:43.130 8259-8259/firebasetest I/System.out:     at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2615)

和 Java 对象：

  public class GroupWithGroupId {
        public long actualLimit, hourLimit,lastGroupId,maxLimit,minLimit;
        public Map<String, Object> groupId = new HashMap<>();
        private GroupWithGroupId(){}

        public GroupWithGroupId(final long actualLimit, final long hourLimit, final long lastGroupId, final long maxLimit, final long minLimit) {
            this.actualLimit = actualLimit;
            this.hourLimit = hourLimit;
            this.lastGroupId = lastGroupId;
            this.maxLimit = maxLimit;
            this.minLimit = minLimit;
        }

        @Exclude
        public Map<String, Object> toMap() {
            HashMap<String, Object> result = new HashMap<>();
            result.put("actualLimit", actualLimit);
            result.put("hourLimit", hourLimit);
            result.put("lastGroupId", lastGroupId);
            result.put("minLimit", minLimit);
            result.put("maxLimit", maxLimit);
            result.put("groupId", groupId);
            return result;
        }
}

【问题讨论】：

标签： android json firebase firebase-realtime-database

【解决方案1】：

您的班级似乎缺少@IgnoreExtraProperties。

尝试以下方法（请注意，我尚未对此进行测试，但希望它会有所帮助！）：

@IgnoreExtraProperties
public class User {

        @IgnoreExtraProperties
        public class Location {

                public Double latitude;
                public Double longitude;

                public Location() {}

                public Location(Double latitude, Double longitude) {
                        this.latitude = latitude;
                        this.longitude = longitude;
                }

                @Exclude
                public Map<String, Object> toMap() {
                        HashMap<String, Object> result = new HashMap<>();
                        result.put("latitude", latitude);
                        result.put("longitude", longitude);
                        return result;
                }
        }

        public String firstName;
        public String lastName;
        public String email;
        public String phone;
        public Location location;
        public Date lastUpdated;
        public Date signUpDate;

        public User() {}

        public User(String firstName, String lastName, String email) {
                this.firstName = firstName;
                this.lastName = lastName;
                this.email = email;
                this.lastUpdated = new Date();
                this.signUpDate = new Date();
        }

        @Exclude
        public Map<String, Object> toMap() {
                HashMap<String, Object> result = new HashMap<>();
                result.put("firstName", firstName);
                result.put("lastName", lastName);
                result.put("email", email);
                result.put("phone", phone);
                result.put("location", location.toMap());
                result.put("lastUpdated", lastUpdated);
                result.put("signUpDate", signUpDate);
                return result;
        }

}

【讨论】：

感谢您的建议。它有所帮助，但我必须修改一下 toMap() 函数才能正常运行。请参阅下面的解决方案

【解决方案2】：

我不得不修改 GroupWithoutGroupId 中的 toMap() 函数，现在它可以正常工作了！

@IgnoreExtraProperties
public class GroupWithoutGroupId {
    public long actualLimit, hourLimit,lastGroupId,maxLimit,minLimit;
    public GroupID groupID;
    public String groupIDkey;

    private GroupWithoutGroupId(){}
    public GroupWithoutGroupId(final long actualLimit, final long hourLimit, final long lastGroupId, final long maxLimit, final long minLimit) {
        this.actualLimit = actualLimit;
        this.hourLimit = hourLimit;
        this.lastGroupId = lastGroupId;
        this.maxLimit = maxLimit;
        this.minLimit = minLimit;
    }

    @Exclude
    public Map<String, Object> toMap() {
        HashMap<String, Object> result = new HashMap<>();
        result.put("actualLimit", actualLimit);
        result.put("hourLimit", hourLimit);
        result.put("lastGroupId", lastGroupId);
        result.put("minLimit", minLimit);
        result.put("maxLimit", maxLimit);
        result.put(groupIDkey, groupID.toMap());
        return result;
    }

    @IgnoreExtraProperties
    public class GroupID {
        public long sum;
        public Map<String, Object> users = new HashMap<>();

        public GroupID(){}
        public GroupID( final long sum, final Map<String, Object> users) {
            this.sum = sum;
            this.users = users;
        }

        @Exclude
        public Map<String, Object> toMap() {
            HashMap<String, Object> result = new HashMap<>();
            result.put("sum", sum);
            result.put("users", users);


       return result;
            }
...

【讨论】：