Java Jackson中的ObjectMapper错误
我有以下课程:Java Jackson中的ObjectMapper错误,java,json,jackson,Java,Json,Jackson,我有以下课程: public class ServletStatus { private int ElapsedTime; private int TotalBusinessImpressionKeywordFailed; private int TotalKeywordStatsFailed; private int TotalRecentSearchesFailed; private int TotalBusinessImpressionKeyword
public class ServletStatus {
private int ElapsedTime;
private int TotalBusinessImpressionKeywordFailed;
private int TotalKeywordStatsFailed;
private int TotalRecentSearchesFailed;
private int TotalBusinessImpressionKeywordSaved;
private int TotalKeywordStatsSaved;
private int TotalRecentSearchesSaved;
private String error;
public String getError() {
return error;
}
public void setError(String error) {
this.error = error;
}
// rest of the getters and setters
}
以及以下JSON:
{"error": "Cannot Accept Request. Servlet has been Shut Down.. "}
我试着阅读如下:
ObjectMapper mapper = new ObjectMapper();
ServletStatus status = mapper.readValue(in, ServletStatus.class);
String strResult = String.format("ElapsedTime(ms): %d, TotalBusinessImpressionKeywordFailed %d, TotalRecentSearchesFailed %d, TotalKeywordStatsFailed %d, TotalBusinessImpressionKeywordSaved %d, TotalKeywordStatsSaved %d, TotalRecentSearchesSaved %d, Success %s ",
status.getElapsedTime(), status.getTotalBusinessImpressionKeywordFailed(), status.getTotalRecentSearchesFailed(), status.getTotalKeywordStatsFailed(), status.getTotalBusinessImpressionKeywordSaved(), status.getTotalKeywordStatsSaved(), status.getTotalRecentSearchesSaved(), status.getError());
我得到以下例外情况:
java.io.EOFException: No content to map to Object due to end of input
at org.codehaus.jackson.map.ObjectMapper._initForReading(ObjectMapper.java:2775)
at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2718)
at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1886)
at nightlybusinessstatsrestart.ShutDownBusinessStatsServlet.showdownServlet(ShutDownBusinessStatsServlet.java:38)
at nightlybusinessstatsrestart.NightlyBusinessStatsRestart.main(NightlyBusinessStatsRestart.java:56)
我做错了什么?我的JSON只包含有错误的错误字段。但是,成功后,我会获得以下附加字段:
ElapsedTime, TotalBusinessImpressionKeywordFailed, TotalKeywordStatsFailed, TotalRecentSearchesFailed, TotalBusinessImpressionKeywordSaved, TotalKeywordStatsSaved, TotalRecentSearchesSaved;
Jackson使用所有属性(字段)为输出生成json,因此当您尝试为对象ServletStatus创建json表示时,您会发现如下内容:
{
ElapsedTime:"",
TotalBusinessImpressionKeywordFailed:"",
TotalKeywordStatsFailed:"",
TotalRecentSearchesFailed="",
.
.
.
error:""
}
如果只想JSON中的错误,请考虑使用
@JsonSerialize(include=JsonSerialize.Inclusion.NON_NULL)
或
如果在json读取期间未包含属性,则避免失败
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);