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Json 字符串到 Java 對象的映射因 jackson 失敗

[英]Json string to java object mapping failed with jackson

 原文  2017-08-15 11:32:34  0   2    java/ json/ jackson/ deserialization/ pojo

問題描述

我正在嘗試將我的 json 映射到 Jackson 的 POJO 類，但我收到的是空值。 如果我刪除@JsonIgnoreProperties 注釋，那么它會拋出無法識別的屬性異常

傑森：

{
   "TileLevel":[

   ],
   "SystemLevel":[
      {
         "Title":"Test System Level Alert",
         "Description":"<div class=\"ExternalClassA5AAC8F74C874A2D9DB8337EB6685B2A\"><p>​Test System Level Alert​<br></p><p>check the url http&#58;//www.google.com<br></p><p><span style=\"font-size&#58;32px;\">formatting tested</span><br></p></div>",
         "AnnouncementType":"System Level",
         "ActiveF":null,
         "TileName":null
      }
   ],
   "Announcements":[
      {
         "Title":"Test Announcement",
         "Description":"<div class=\"ExternalClass16980D07D2FB4AB58A2E97C16B7626D3\"><p>​Testing.....&#160;<img src=\"/sites/salesbk-CN/SiteCollectionImages/Salesbook%20Announcements/AllItems/00007-confiz-test-doc7.png\" alt=\"00007-confiz-test-doc7.png\" style=\"margin&#58;5px;\" /><br></p></div>",
         "AnnouncementType":"Announcement",
         "ActiveF":null,
         "TileName":null
      }
   ]
}

我將此json作為字符串獲取，然后嘗試將此字符串轉換為java對象。

這是我的 POJO 課程：

public class SPOAnnouncement {

    @JsonIgnoreProperties
    private Map<String, List<List<SPOAnnouncements_Properties>>> TileLevel;
    private Map<String, List<List<SPOAnnouncements_Properties>>> SystemLevel;
    private Map<String, List<List<SPOAnnouncements_Properties>>> Announcements;

    public Map<String, List<List<SPOAnnouncements_Properties>>> getTileLevel() {
        return TileLevel;
    }

    public void setTileLevel(Map<String, List<List<SPOAnnouncements_Properties>>> tileLevel) {
        TileLevel = tileLevel;
    }

    public Map<String, List<List<SPOAnnouncements_Properties>>> getSystemLevel() {
        return SystemLevel;
    }

    public void setSystemLevel(Map<String, List<List<SPOAnnouncements_Properties>>> systemLevel) {
        SystemLevel = systemLevel;
    }

    public Map<String, List<List<SPOAnnouncements_Properties>>> getAnnouncements() {
        return Announcements;
    }

    public void setAnnouncements(Map<String, List<List<SPOAnnouncements_Properties>>> announcements) {
        Announcements = announcements;
    }
}


public class SPOAnnouncements_Properties {


    private String Title;
    private String Description;
    private String AnnouncementType;
    private String ActiveF;
    private String TileName;

    public String getTitle() {
        return Title;
    }

    public void setTitle(String title) {
        Title = title;
    }

    public String getDescription() {
        return Description;
    }

    public void setDescription(String description) {
        Description = description;
    }

    public String getAnnouncementType() {
        return AnnouncementType;
    }

    public void setAnnouncementType(String announcementType) {
        AnnouncementType = announcementType;
    }

    public String getActiveF() {
        return ActiveF;
    }

    public void setActiveF(String activeF) {
        ActiveF = activeF;
    }

    public String getTileName() {
        return TileName;
    }

    public void setTileName(String tileName) {
        TileName = tileName;
    }

}

我驗證結果是否已映射到 json 對象的測試方法：

@Test
public void convertJsonToObject() throws IOException {

    ObjectMapper mapper = new ObjectMapper();
    mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
    SPOAnnouncement spoAnnouncement = mapper.readValue(response, SPOAnnouncement.class);
    System.out.print(spoAnnouncement);
}

2 個解決方案

解決方案1
 1 已采納  2017-08-15 12:20:30

您的 POJO 結構無效。 查看http://www.jsonschema2pojo.org - 一個用於從 JSON 生成 Java POJO 的在線工具。

您的類應該或多或少如下所示，但您需要用首選類型替換ActiveF和TileName字段。

-----------------------------------com.example.Announcement.java-----------------------------------

package com.example;

import java.util.HashMap;
import java.util.Map;
import com.fasterxml.jackson.annotation.JsonAnyGetter;
import com.fasterxml.jackson.annotation.JsonAnySetter;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
        "Title",
        "Description",
        "AnnouncementType",
        "ActiveF",
        "TileName"
})
public class Announcement {

    @JsonProperty("Title")
    private String title;
    @JsonProperty("Description")
    private String description;
    @JsonProperty("AnnouncementType")
    private String announcementType;
    @JsonProperty("ActiveF")
    private Object activeF;
    @JsonProperty("TileName")
    private Object tileName;
    @JsonIgnore
    private Map<String, Object> additionalProperties = new HashMap<String, Object>();

    @JsonProperty("Title")
    public String getTitle() {
        return title;
    }

    @JsonProperty("Title")
    public void setTitle(String title) {
        this.title = title;
    }

    @JsonProperty("Description")
    public String getDescription() {
        return description;
    }

    @JsonProperty("Description")
    public void setDescription(String description) {
        this.description = description;
    }

    @JsonProperty("AnnouncementType")
    public String getAnnouncementType() {
        return announcementType;
    }

    @JsonProperty("AnnouncementType")
    public void setAnnouncementType(String announcementType) {
        this.announcementType = announcementType;
    }

    @JsonProperty("ActiveF")
    public Object getActiveF() {
        return activeF;
    }

    @JsonProperty("ActiveF")
    public void setActiveF(Object activeF) {
        this.activeF = activeF;
    }

    @JsonProperty("TileName")
    public Object getTileName() {
        return tileName;
    }

    @JsonProperty("TileName")
    public void setTileName(Object tileName) {
        this.tileName = tileName;
    }

    @JsonAnyGetter
    public Map<String, Object> getAdditionalProperties() {
        return this.additionalProperties;
    }

    @JsonAnySetter
    public void setAdditionalProperty(String name, Object value) {
        this.additionalProperties.put(name, value);
    }

}
-----------------------------------com.example.SPOAnnouncement.java-----------------------------------

package com.example;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.fasterxml.jackson.annotation.JsonAnyGetter;
import com.fasterxml.jackson.annotation.JsonAnySetter;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
        "TileLevel",
        "SystemLevel",
        "Announcements"
})
public class SPOAnnouncement {

    @JsonProperty("TileLevel")
    private List<Object> tileLevel = null;
    @JsonProperty("SystemLevel")
    private List<SystemLevel> systemLevel = null;
    @JsonProperty("Announcements")
    private List<Announcement> announcements = null;
    @JsonIgnore
    private Map<String, Object> additionalProperties = new HashMap<String, Object>();

    @JsonProperty("TileLevel")
    public List<Object> getTileLevel() {
        return tileLevel;
    }

    @JsonProperty("TileLevel")
    public void setTileLevel(List<Object> tileLevel) {
        this.tileLevel = tileLevel;
    }

    @JsonProperty("SystemLevel")
    public List<SystemLevel> getSystemLevel() {
        return systemLevel;
    }

    @JsonProperty("SystemLevel")
    public void setSystemLevel(List<SystemLevel> systemLevel) {
        this.systemLevel = systemLevel;
    }

    @JsonProperty("Announcements")
    public List<Announcement> getAnnouncements() {
        return announcements;
    }

    @JsonProperty("Announcements")
    public void setAnnouncements(List<Announcement> announcements) {
        this.announcements = announcements;
    }

    @JsonAnyGetter
    public Map<String, Object> getAdditionalProperties() {
        return this.additionalProperties;
    }

    @JsonAnySetter
    public void setAdditionalProperty(String name, Object value) {
        this.additionalProperties.put(name, value);
    }

}
-----------------------------------com.example.SystemLevel.java-----------------------------------

package com.example;

import java.util.HashMap;
import java.util.Map;
import com.fasterxml.jackson.annotation.JsonAnyGetter;
import com.fasterxml.jackson.annotation.JsonAnySetter;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
        "Title",
        "Description",
        "AnnouncementType",
        "ActiveF",
        "TileName"
})
public class SystemLevel {

    @JsonProperty("Title")
    private String title;
    @JsonProperty("Description")
    private String description;
    @JsonProperty("AnnouncementType")
    private String announcementType;
    @JsonProperty("ActiveF")
    private Object activeF;
    @JsonProperty("TileName")
    private Object tileName;
    @JsonIgnore
    private Map<String, Object> additionalProperties = new HashMap<String, Object>();

    @JsonProperty("Title")
    public String getTitle() {
        return title;
    }

    @JsonProperty("Title")
    public void setTitle(String title) {
        this.title = title;
    }

    @JsonProperty("Description")
    public String getDescription() {
        return description;
    }

    @JsonProperty("Description")
    public void setDescription(String description) {
        this.description = description;
    }

    @JsonProperty("AnnouncementType")
    public String getAnnouncementType() {
        return announcementType;
    }

    @JsonProperty("AnnouncementType")
    public void setAnnouncementType(String announcementType) {
        this.announcementType = announcementType;
    }

    @JsonProperty("ActiveF")
    public Object getActiveF() {
        return activeF;
    }

    @JsonProperty("ActiveF")
    public void setActiveF(Object activeF) {
        this.activeF = activeF;
    }

    @JsonProperty("TileName")
    public Object getTileName() {
        return tileName;
    }

    @JsonProperty("TileName")
    public void setTileName(Object tileName) {
        this.tileName = tileName;
    }

    @JsonAnyGetter
    public Map<String, Object> getAdditionalProperties() {
        return this.additionalProperties;
    }

    @JsonAnySetter
    public void setAdditionalProperty(String name, Object value) {
        this.additionalProperties.put(name, value);
    }

}

如果您正在創建網絡服務，請記住將它們序列化；)。

解決方案2
 0  2020-08-30 07:28:30

您可以使用@JsonProperty("FieldName")表示法來映射所有未映射的字段。 但 FieldName 必須與 JSON 字符串中的確切字段名稱匹配。

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