使用jackson将java对象转换为json字符串时，重复的json属性 [英] Duplicate json property when converting java object to json string using jackson

问题描述

我有Pojo对象，使用getAsJson函数返回此对象的Json字符串。
我使用JsonProperty定义此对象中的json属性。
使用ObjectMapper的writeValueAsString为该对象写入json字符串。

  import org.codehaus.jackson.JsonGenerationException; 
 import org.codehaus.jackson.annotate.JsonIgnore; 
 import org.codehaus.jackson.annotate.JsonIgnoreProperties; 
 import org.codehaus.jackson.annotate.JsonProperty; 
 import org.codehaus.jackson.map.JsonMappingException; 
 import org.codehaus.jackson.map.ObjectMapper; 
 
 @JsonIgnoreProperties（ignoreUnknown = true）
 public class LogLikeArticleDetail extends BaseObject {
 private static final long serialVersionUID = -2018373118257019033L; 
 @JsonProperty（LikeArticleGUId）
 private String likeArticleGUId; 
 @JsonProperty（UserId）
 private String userID; 
 @JsonProperty（UserName）
 private String userName; 
 @JsonProperty（IP）
 private String ip; 
 @JsonProperty（OS）
 private String os; 
 @JsonProperty（UserAgent）
 private String userAgent; 
 @JsonProperty（WebsiteCode）
 private String websiteCode; 
 @JsonProperty（ArticleId）
 private String articleID; 
 @JsonProperty（ATitle）
 private String aTitle; 
 @JsonProperty（CateAlias）
 private String cateAlias; 
 @JsonProperty（LikeStatus）
 private String likeStatus; 
 @JsonProperty（TimeStamp）
 private Date timeStamp; 
 // get，set .... 
 // .... 
 @JsonIgnore 
 public String getAsJSON（）throws JsonGenerationException，JsonMappingException，IOException {
 ObjectMapper mapper = new ObjectMapper（）; 
 return mapper.writeValueAsString（this）; 
} 
} 
  

现在，我得到结果

  public static void main（String [] args）throws JsonGenerationException，JsonMappingException，IOException {
 Calendar calendar = Calendar.getInstance（）; 
 LogLikeArticleDetail logLikeArticle = new LogLikeArticleDetail（1，2，3，4，5，6，7，8，什么东西\\ \\show，10，11，calendar.getTime（））; 
 System.out.println（logLikeArticle.getAsJSON（））; 
} 
  

但结果重复的属性：

  {LikeArticleGUId：1，UserId：2，UserName：3，IP：4 ：5，UserAgent：6，WebsiteCode：7，ArticleId：8，ATitle：什么东西\ 10， likeStatus： 11， 时间戳：1352256727062， _ likeArticleGUId： 1， websiteCode： 7， likeStatus： 11， 用户ID： 2， userName：3，ip：4，os：5，userAgent：6，articleID：8，aTitle没有\\显示，cateAlias：10，timeStamp：1352256727062} 
  

告诉我这个问题发生了什么？

解决方案

所以我遵循：
如何指定杰克逊只使用字段 - 最好是全局

我添加

  @JsonAutoDetect（fieldVisibility = Visibilit y.ANY，getterVisibility = Visibility.NONE，setterVisibility = Visibility.NONE）
  

before

  public class LogLikeArticleDetail extends BaseObject 
  

，我想要的结果。

所以可以在getAsJson（）函数中另一个解决方案，如：

  ObjectMapper mapper = new ObjectMapper（）; 
 mapper.setVisibilityChecker（mapper.getSerializationConfig（）。getDefaultVisibilityChecker（）
 .withFieldVisibility（JsonAutoDetect.Visibility.ANY）
 .withGetterVisibility（JsonAutoDetect.Visibility.NONE）
 .withSetterVisibility JsonAutoDetect.Visibility.NONE）
 .withCreatorVisibility（JsonAutoDetect.Visibility.NONE））; 
 return mapper.writeValueAsString（this）;感谢@Sean Carpenter的问题和@ kmb385的回答，链接上面。
 $ $ $ $ $ $ $ $ $ $ $ $ 
I have Pojo object, with getAsJson function to return Json string for this object.
I use JsonProperty to define json properties in this object.
Use writeValueAsString of ObjectMapper to write json string for this object.
import org.codehaus.jackson.JsonGenerationException;
import org.codehaus.jackson.annotate.JsonIgnore;
import org.codehaus.jackson.annotate.JsonIgnoreProperties;
import org.codehaus.jackson.annotate.JsonProperty;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;

@JsonIgnoreProperties(ignoreUnknown=true)
public class LogLikeArticleDetail extends BaseObject {
    private static final long serialVersionUID = -2018373118257019033L;
    @JsonProperty("LikeArticleGUId")
    private String likeArticleGUId;
    @JsonProperty("UserId")
    private String userID;
    @JsonProperty("UserName")
    private String userName;
    @JsonProperty("IP") 
    private String ip;
    @JsonProperty("OS") 
    private String os;
    @JsonProperty("UserAgent") 
    private String userAgent;
    @JsonProperty("WebsiteCode") 
    private String websiteCode;
    @JsonProperty("ArticleId") 
    private String articleID;
    @JsonProperty("ATitle") 
    private String aTitle;
    @JsonProperty("CateAlias") 
    private String cateAlias;
    @JsonProperty("LikeStatus") 
    private String likeStatus;
    @JsonProperty("TimeStamp") 
    private Date timeStamp;
        //get, set....
        //....
        @JsonIgnore
    public String getAsJSON() throws JsonGenerationException, JsonMappingException,    IOException{
        ObjectMapper mapper = new ObjectMapper();
        return mapper.writeValueAsString(this) ; 
    }
}
Now, i get result
public static void main(String[] args) throws JsonGenerationException, JsonMappingException, IOException {
        Calendar calendar =  Calendar.getInstance();
        LogLikeArticleDetail logLikeArticle = new LogLikeArticleDetail("1","2","3","4","5","6","7","8","what thing \"nothing\" show","10","11",calendar.getTime());
        System.out.println(logLikeArticle.getAsJSON());
    }
But the result's duplicated properties:
{"LikeArticleGUId":"1","UserId":"2","UserName":"3","IP":"4","OS":"5","UserAgent":"6","WebsiteCode":"7","ArticleId":"8","ATitle":"what thing \"nothing\" show","CateAlias":"10","LikeStatus":"11","TimeStamp":1352256727062,"_likeArticleGUId":"1","websiteCode":"7","likeStatus":"11","userID":"2","userName":"3","ip":"4","os":"5","userAgent":"6","articleID":"8","aTitle":"what thing \"nothing\" show","cateAlias":"10","timeStamp":1352256727062}
Show me what's occur in this problem ?
解决方案
So i do follow:
how to specify jackson to only use fields - preferably globally

I add 
@JsonAutoDetect(fieldVisibility = Visibility.ANY, getterVisibility = Visibility.NONE, setterVisibility = Visibility.NONE)
before
public class LogLikeArticleDetail extends BaseObject
and the result that i want.

So can another solve that in getAsJson() function like:
ObjectMapper mapper  = new ObjectMapper();
mapper.setVisibilityChecker(mapper.getSerializationConfig().getDefaultVisibilityChecker()
                .withFieldVisibility(JsonAutoDetect.Visibility.ANY)
                .withGetterVisibility(JsonAutoDetect.Visibility.NONE)
                .withSetterVisibility(JsonAutoDetect.Visibility.NONE)
                .withCreatorVisibility(JsonAutoDetect.Visibility.NONE));
return mapper.writeValueAsString(this) ;
Thanks for @Sean Carpenter 's question and @kmb385 answer in link above.

                        
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