您在尝试将zson响应解析为zk框架上的java时遇到错误
这是杰森回复
{"currentTime":1355390722038,"text":"OK","data":{"limitExceeded":false,"references":{"stops":[],"situations":[],"trips":[],"routes":[],"agencies":[{"id":"AG1","privateService":false,"phone":"","timezone":"Asia/Kuala_Lumpur","disclaimer":"","name":"Panorama","lang":"en","url":"http://www.allcompanyonline.com/company/33/8/26/62438/PM-Cultural--Tourism-Sdn-Bhd.html"}]},"list":[{"lonSpan":0.1766824722290039,"lon":102.2011971473685,"agencyId":"AG1","lat":2.2659808772471948,"latSpan":0.15555363245723042}]},"code":200,"version":2}
我一直收到此错误
com.fasterxml.jackson.databind.JsonMappingException: Can not instantiate value of type [simple type, class com.panorama.tripplan.pojo.Agency_coverage] from Long integral number; no single-long-arg constructor/factory method
这里是根变量的pojo
@JsonRootName(value = "currentTime")
public class Agency_coverage{
private Number code;
private Number currentTime;
private Data data;
private String text;
private Number version;
public Agency_coverage(){}
public Number getCode(){
return this.code;
}
public void setCode(Number code){
this.code = code;
}
public Number getCurrentTime(){
return this.currentTime;
}
public void setCurrentTime(Number currentTime){
this.currentTime = currentTime;
}
public Data getData(){
return this.data;
}
public void setData(Data data){
this.data = data;
}
public String getText(){
return this.text;
}
public void setText(String text){
this.text = text;
}
public Number getVersion(){
return this.version;
}
public void setVersion(Number version){
this.version = version;
}
这里是我尝试调用api并解析响应的代码
java.net.URLConnection connection = new URL(url + "?" + query+ "&" + queryLat+ "&" + queryLon).openConnection();
connection.setRequestProperty("Accept-Charset", charset);
if ( connection instanceof HttpURLConnection)
{
//Jackson 2.X configuration settings
mapper.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true);
mapper.configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true);
mapper.configure(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT, true);
mapper.configure(DeserializationFeature.USE_JAVA_ARRAY_FOR_JSON_ARRAY, true);
mapper.configure(DeserializationFeature.READ_ENUMS_USING_TO_STRING, true);
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
//Tell Jackson to expect the JSON in PascalCase, instead of camelCase
mapper.setPropertyNamingStrategy(new PropertyNamingStrategy.PascalCaseStrategy());
HttpURLConnection httpConnection =(HttpURLConnection) connection;
//Make the HTTP request, and deserialize the JSON response into the object
Agency_coverage agencyData= new Agency_coverage();
agencyData = mapper.readValue(agenturl, Agency_coverage.class);
//System.out.println(agencyData.getData().getList().get(0).);
System.out.println(agencyData.getCurrentTime());
System.out.println(httpConnection.getResponseCode());
}
请帮助,如果你能理解这个问题,我对java开发有点新,并且给我全部了
答案 0 :(得分:7)
首先要删除@JsonRootName(value = "currentTime")
注释为@aymeric建议。这个注释告诉Jackson映射器,当你的POJO调用这个东西'Agency_coverage'时,匹配的JSON对象将调用它'currentTime'。事实并非如此。
现在,除此之外,您的JSON看起来应该更像这样:
{"Agency_coverage":{"currentTime":1355390722038,"text":"OK","data":"etc..."}}
这里的不同之处在于,您正在为杰克逊提供解包的根元素。
你现在可以看到杰克逊的错误在说什么。使用您提供的JSON和您使用的注释,它找到了currentTime
作为JSON元素,它映射到Agency_coverage
POJO,但currentTime
的值是long
并且无法映射。