标签: jackson

我正在使用JSON Jackson 2.0将数据模型写入文件,然后将其加载回应用程序.我可以成功地将对象写入字符串,但在尝试将其编组回对象时遇到以下错误消息:

找不到类型[simple type,class ImportAttributeModel]的合适构造函数:无法在[Source:user;来自JSON对象(需要添加/启用类型信息？)实例化)line:1,column:111](通过引用链:ImportTemplateModel ["modelList"])

这是我的类的代码片段:

public class ImportTemplateModel 
{  
  private Map<Integer, AttributeModel> m_modelList;
  private GraphElementType m_type; 

  public ImportTemplateModel() 
  {

  }
// getters  & setters
}

public class AttributeModel 
{
   private String m_label;
   private String m_key;
   private ElementDefinition m_definition;

   public AttributeModel(String label, String key, ElementDefinition def)
   {
      m_label = label;
      m_key = key;
      m_definition = def;
   }
// getters  & setters
}

这是我写的和读取模型的调用:

// Write model
ObjectMapper mapper = new ObjectMapper();
ImportTemplateModel itm = new ImportTemplateModel()
// set …

我response给了我null价值观,但当我运行同样的东西时fiddler,我得到了很多数据.我编写的代码非常少,并使用在线工具生成代码.我想知道我搞砸了.

    Publications response = null ;
    // First open URL connection (using JDK; similar with other libs)
    try {
        URL url = new URL(
                "http://myserver:myport/Mobile/GetPublications");
        HttpURLConnection connection = (HttpURLConnection)url.openConnection() ;
        connection.setDoInput(true);
        connection.setDoOutput(true);
        connection.setRequestMethod("POST") ;
        connection.setRequestProperty("Content-Type", "application/json") ;
        // and other configuration if you want, timeouts etc
        // then send JSON request
        Publications request = new Publications(); // POJO with getters or public fields
        ObjectMapper mapper = new ObjectMapper(); 
        mapper.writeValue(connection.getOutputStream(), request);
        // and read response …

如何将POJO映射到几个JSON演示文稿？

我在用杰克逊.

我想要下面的代码

@JsonIgnorePropertiesStreamA({ "value2" })
@JsonIgnorePropertiesOtherWay({ "value3" })
public class Value {
  public int value;
  public int value2;
  public int value3;
}

如何与杰克逊一起做？或者其他图书馆可以做什么？

我正在尝试使用Spring for Android和Jackson 2从休息呼叫中创建一个POJO.

// Set the Accept header
HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.setAccept(Collections.singletonList(new MediaType("application","vnd.livescore_app.api.v1+json")));
requestHeaders.setContentType(new MediaType("application","json;charset=utf-8"));
HttpEntity<?> requestEntity = new HttpEntity<Object>(requestHeaders);

// Create a new RestTemplate instance
RestTemplate restTemplate = new RestTemplate();

// Add the Jackson message converter
restTemplate.getMessageConverters().add( new MappingJackson2HttpMessageConverter());

// Make the HTTP GET request, marshaling the response from JSON to an array of Events
ResponseEntity<AppVersionObject> responseEntity = restTemplate.exchange("https://example.com", HttpMethod.GET, requestEntity, AppVersionObject.class);
AppVersionObject object = responseEntity.getBody();

使用以下日志跟踪崩溃

05-13 10:55:42.656: E/AndroidRuntime(19401): FATAL EXCEPTION: Thread-1470
05-13 10:55:42.656: E/AndroidRuntime(19401): …

我想使用canDeserialize方法，因为在反序列化时，我想获取要在自定义反序列化中应用的类型类，如以下示例所示：

    public T deserialize(byte[] bytes) throws SerializationException {
       bolean isAccount = this.objectMapper.canDeserialize(??????).
           T t = null;

          if(isAccount)
            t = (T)this.objectMapper.readValue(bytes,Account.class);

          else 
            t = (T) this.objectMapper.readValue(bytes, 0, bytes.length, new TypeReference<Object>(){});

         return t;
    }

在这种情况下，Account类具有@JsonDeserialize注释，用于自定义反序列化。

我最近开始开发rest apis并且偶然发现了这些条款 - jetty,jackson&jersey.我在普通日食时使用球衣成功开发了休息api.

我相信jackson是为了促进xml/java对象的反序列化和序列化.但它是什么 - 它只是一个jar文件的集合？ - 如果是的话,如果我已经在使用jersey框架(如果我的apis处理xmls),我可以/我应该同时使用它吗？

同样,什么即Jetty - 我下载它并看到了很多文件夹和文件 - 而且它们不仅仅是罐子的集合!如果它是一个框架,我可以在球衣上使用它吗？如果是的话,它看起来很重 - 我认为处理HTML内容可能只是几个罐子.但看起来还有很多东西.

如果我的apis处理所有媒体类型,这三件事情是否可以一起使用？如果是,那么最好的方法是什么？

谢谢.

我正在尝试使用jackson api解析json,并提供以下详细信息.但是我收到了错误.请查找代码和堆栈跟踪的以下详细信息.

JSON

[{"id":1001,"cyPerReffe":1200,"distPercentage":"0"},{"id":1002,"cyPerReffe":1000,"distPercentage":"10"},{"id":1003,"cyPerReffe":800,"distPercentage":"20"},{"id":1004,"cyPerReffe":750,"distPercentage":"10"},{"id":1005,"cyPerReffe":700,"distPercentage":"10"},{"id":1006,"cyPerReffe":650,"distPercentage":"10"},{"id":1007,"cyPerReffe":600,"distPercentage":"20"},{"id":1008,"cyPerReffe":300,"distPercentage":"5"},{"id":1009,"cyPerReffe":333,"distPercentage":"7"},{"id":1010,"cyPerReffe":"32","distPercentage":"8"}]

控制器类

ObjectMapper mapper = new ObjectMapper();   mapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);
PublisheDataList publisheDataList = mapper.convertValue(json, PublisheDataList.class);

以下类是我的bean类. PublisheData.java

private Long id;
private Long cyPerReffe;
private String distPercentage;
//    with setter and getters

PublisheDataList.java

List<PublisheData> publisheDataList;
//with setter and getters

我收到以下错误.

java.lang.IllegalArgumentException: Can not deserialize instance of models.PublisheDataList out of START_ARRAY token
 at [Source: N/A; line: -1, column: -1]
        at org.codehaus.jackson.map.ObjectMapper._convert(ObjectMapper.java:2502)
        at org.codehaus.jackson.map.ObjectMapper.convertValue(ObjectMapper.java:2468)
        at controllers.RYSController.publishReferenceYield(RYSController.java:79)
        at Routes$$anonfun$routes$1$$anonfun$applyOrElse$22$$anonfun$apply$62.apply(routes_routing.scala:318)
        at Routes$$anonfun$routes$1$$anonfun$applyOrElse$22$$anonfun$apply$62.apply(routes_routing.scala:318)
        at play.core.Router$HandlerInvoker$$anon$6$$anon$2.invocation(Router.scala:175)
        at play.core.Router$Routes$$anon$1.invocation(Router.scala:355)
        at play.core.j.JavaAction$$anon$1.call(JavaAction.scala:50)
        at play.GlobalSettings$1.call(GlobalSettings.java:63)
        at play.core.j.JavaAction$$anon$2.apply(JavaAction.scala:80)
        at …

我有以下JSON:

"propertyName": "{"1":[{"1":"value1","2":"value2","3":false}]}"

第一个属性是具有属性映射后数组中项目的计数.

如果我想填写一个包含这些值的类,那么使用Jackson对此进行反序列化的最佳方法是:

class MyHolder
{
   name = "value1";
   age = "value2";
   female = false;
}

例如.

我有一个从API返回的JSON,所以我无法更改它,问题是其中一个属性有时是一个空字符串,有时它是一个对象.

有时当我调用它时,foo是一个空字符串

{ 
 "foo" : "",
 "bar" : 0
}

而在其他时候它是一个对象

{
 "foo" : {"baz": 11},
 "bar" : 2
}

有没有办法用杰克逊做到这一点？到目前为止,我发现的唯一方法是编写自定义解串器/串行器对.我对这种方法的问题是,这是一个深度嵌套的JSON结构,并且违规属性接近根...

这是我的控制器.

@RequestMapping(value="/updateItem.htm", method = RequestMethod.GET, headers="Accept=*/*", produces = "application/json; charset=utf-8")    
public @ResponseBody ModelAndView updateItem(ModelAndView model) {
                    List<String> list = aspireDAO.getSingleCol("select prod_id from items order by prod_id asc");
                    JsonArray jArray = AspireUtil.toJsonArray(list);
                    model.setViewName("UpdateItem");
            model.addObject("items", jArray);
                    System.out.println(jArray);
            return model;
        }

对于spring-servlet.xml中的jackson支持

<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
      <property name="mediaTypes">
        <map>
          <entry key="html" value="text/html"/>
          <entry key="json" value="application/json"/>
        </map>
      </property>
      <property name="defaultViews">
        <list>
          <bean class="org.springframework.web.servlet.view.json.MappingJacksonJsonView">
            <property name="prefixJson" value="true"/>
          </bean>
        </list>
      </property>
    </bean>

json数组在我的控制器sysout语句中很好用.当我检查页面的源时,json数组就像这样打印

'["amgc","atup","ciwy","eyqe","ijm

可能是什么原因.如何解决它.

问候

AADAM