我不能把这个json转换成pojo (java类)

Question

我不能将这个json转换成java类，我在这个json文件中有" value“的问题，一些位置的值是数组，一些位置的值是jost key值！！我使用IntelliJ，这是我的错误：

2017-09-18 14:43:21.540  WARN 5496 --- [apr-8080-exec-2]  .w.s.m.s.DefaultHandlerExceptionResolver : Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: Could not read document: Can not deserialize instance of com.ada.bean.response.Issue out of START_ARRAY token

在源：(PushbackInputStream)；行: 1，列: 1；嵌套异常是com.fasterxml.jackson.databind.JsonMappingException:无法从源：(PushbackInputStream)的START_ARRAY令牌反序列化com.ada.bean.response.Issue的实例；行: 1，列:1

这是我的json：

[
{
"id": "ETC-1",
"entityId": "94-5024",
"jiraId": null,
"field": [
  {
    "name": "projectShortName",
    "value": "ETC"
  },
  {
    "name": "numberInProject",
    "value": "1"
  },
  {
    "name": "summary",
    "value": "????? API ??? Youtrack ? ????? ?? ??"
  },
  {
    "name": "created",
    "value": "1504079347372"
  },
  {
    "name": "updated",
    "value": "1504341622265"
  },
  {
    "name": "updaterName",
    "value": "a.fathizade"
  },
  {
    "name": "updaterFullName",
    "value": "Ali Fathizadeh"
  },
  {
    "name": "resolved",
    "value": "1504341622257"
  },
  {
    "name": "reporterName",
    "value": "v.sabeti"
  },
  {
    "name": "reporterFullName",
    "value": "???? ?????"
  },
  {
    "name": "commentsCount",
    "value": "0"
  },
  {
    "name": "votes",
    "value": "0"
  },
  {
    "name": "Priority",
    "value": [
      "Normal"
    ],
    "valueId": [
      "Normal"
    ],
    "color": {
      "bg": "#e6f6cf",
      "fg": "#4da400"
    }
  },
  {
    "name": "Type",
    "value": [
      "Task"
    ],
    "valueId": [
      "Task"
    ],
    "color": null
  },
  {
    "name": "State",
    "value":  [
      "Fixed"
    ],
    "valueId": [
      "Fixed"
    ],
    "color": null
  },
  {
    "name": "Assignee",
    "value": [
      {
        "value": "a.fathizade",
        "fullName": "Ali Fathizadeh"
      }
    ]
  },
  {
    "name": "Subsystem",
    "value": [
      "Employees"
    ],
    "valueId": [
      "Employees"
    ],
    "color": {
      "bg": "#ff7123",
      "fg": "#fff"
    }
  },
  {
    "name": "sprint",
    "value": [
      {
        "value": "First sprint",
        "id": "Etc Board:First sprint"
      }
    ]
  }
],
"comment": [],
"tag": []
},
{
"id": "ETC-2",
"entityId": "94-5026",
"jiraId": null,
"field": [
  {
    "name": "projectShortName",
    "value": "ETC"
  },
  {
    "name": "numberInProject",
    "value": "2"
  },
  {
    "name": "summary",
    "value": "???? ?????? ???? ? ??? ??? ????"
  },
  {
    "name": "created",
    "value": "1504079557400"
  },
  {
    "name": "updated",
    "value": "1504341630002"
  },
  {
    "name": "updaterName",
    "value": "a.fathizade"
  },
  {
    "name": "updaterFullName",
    "value": "Ali Fathizadeh"
  },
  {
    "name": "resolved",
    "value": "1504341629992"
  },
  {
    "name": "reporterName",
    "value": "v.sabeti"
  },
  {
    "name": "reporterFullName",
    "value": "???? ?????"
  },
  {
    "name": "commentsCount",
    "value": "0"
  },
  {
    "name": "votes",
    "value": "0"
  },
  {
    "name": "Priority",
    "value": [
      "Normal"
    ],
    "valueId": [
      "Normal"
    ],
    "color": {
      "bg": "#e6f6cf",
      "fg": "#4da400"
    }
  },
  {
    "name": "Type",
    "value": [
      "Task"
    ],
    "valueId": [
      "Task"
    ],
    "color": null
  },
  {
    "name": "State",
    "value": [
      "Fixed"
    ],
    "valueId": [
      "Fixed"
    ],
    "color": null
  },
  {
    "name": "Assignee",
    "value": [
      {
        "value": "a.fathizade",
        "fullName": "Ali Fathizadeh"
      }
    ]
  },
  {
    "name": "Subsystem",
    "value": [
      "Employees"
    ],
    "valueId": [
      "Employees"
    ],
    "color": {
      "bg": "#ff7123",
      "fg": "#fff"
    }
  },
  {
    "name": "sprint",
    "value": [
      {
        "value": "First sprint",
        "id": "Etc Board:First sprint"
      }
    ]
  }
 ],
 "comment": [],
 "tag": []
 },
 {
"id": "ETC-4",
"entityId": "94-5030",
"jiraId": null,
"field": [
  {
    "name": "projectShortName",
    "value": "ETC"
  },
  {
    "name": "numberInProject",
    "value": "4"
  },
  {
    "name": "summary",
    "value": "????? ??????? ???? ?? Youtrack ? ????? ?? ?? ?????? ????"
  },
  {
    "name": "created",
    "value": "1504079626044"
  },
  {
    "name": "updated",
    "value": "1504341630988"
  },
  {
    "name": "updaterName",
    "value": "a.fathizade"
  },
  {
    "name": "updaterFullName",
    "value": "Ali Fathizadeh"
  },
  {
    "name": "reporterName",
    "value": "v.sabeti"
  },
  {
    "name": "reporterFullName",
    "value": "???? ?????"
  },
  {
    "name": "commentsCount",
    "value": "0"
  },
  {
    "name": "votes",
    "value": "0"
  },
  {
    "name": "Priority",
    "value": [
      "Normal"
    ],
    "valueId": [
      "Normal"
    ],
    "color": {
      "bg": "#e6f6cf",
      "fg": "#4da400"
    }
  },
  {
    "name": "Type",
    "value": [
      "Task"
    ],
    "valueId": [
      "Task"
    ],
    "color": null
  },
  {
    "name": "State",
    "value": [
      "In Progress"
    ],
    "valueId": [
      "In Progress"
    ],
    "color": null
    },
    {
      "name": "Assignee",
     "value": [
       {
        "value": "a.fathizade",
        "fullName": "Ali Fathizadeh"
      }
    ]
  },
  {
    "name": "Subsystem",
    "value": [
      "Employees"
    ],
    "valueId": [
      "Employees"
    ],
    "color": {
      "bg": "#ff7123",
      "fg": "#fff"
    }
  },
  {
    "name": "sprint",
    "value": [
      {
        "value": "First sprint",
        "id": "Etc Board:First sprint"
      }
    ]
  }
],
"comment": [],
"tag": []
},
{
"id": "ETC-5",
"entityId": "94-5032",
"jiraId": null,
"field": [
  {
    "name": "projectShortName",
    "value": "ETC"
  },
  {
    "name": "numberInProject",
    "value": "5"
  },
  {
    "name": "summary",
    "value": "Parse ???? ??????? ???? Excel ????????"
  },
  {
    "name": "created",
    "value": "1504079740110"
  },
  {
    "name": "updated",
    "value": "1505302061947"
  },
  {
    "name": "updaterName",
    "value": "a.fathizade"
  },
  {
    "name": "updaterFullName",
    "value": "Ali Fathizadeh"
  },
  {
    "name": "resolved",
    "value": "1505302061939"
  },
  {
    "name": "reporterName",
    "value": "v.sabeti"
  },
  {
    "name": "reporterFullName",
    "value": "???? ?????"
  },
  {
    "name": "commentsCount",
    "value": "0"
  },
  {
    "name": "votes",
    "value": "0"
  },
  {
    "name": "Priority",
    "value": [
      "Normal"
    ],
    "valueId": [
      "Normal"
    ],
    "color": {
      "bg": "#e6f6cf",
      "fg": "#4da400"
    }
  },
  {
    "name": "Type",
    "value": [
      "Task"
    ],
    "valueId": [
      "Task"
    ],
    "color": null
  },
  {
    "name": "State",
    "value": [
      "Fixed"
    ],
    "valueId": [
      "Fixed"
    ],
    "color": null
  },
  {
    "name": "Assignee",
    "value": [
      {
        "value": "a.fathizade",
        "fullName": "Ali Fathizadeh"
      }
    ]
  },
  {
    "name": "Subsystem",
    "value": [
      "Employees"
    ],
    "valueId": [
      "Employees"
    ],
    "color": {
      "bg": "#ff7123",
      "fg": "#fff"
    }
  },
  {
    "name": "sprint",
    "value": [
      {
        "value": "First sprint",
        "id": "Etc Board:First sprint"
      }
    ]
  }
 ],
 "comment": [],
 "tag": []
 },
 {
"id": "ETC-6",
"entityId": "94-5034",
"jiraId": null,
"field": [
  {
    "name": "projectShortName",
    "value": "ETC"
  },
  {
    "name": "numberInProject",
    "value": "6"
  },
  {
    "name": "summary",
      "value": "????? ??????? Youtrack ????? ?? DB ?? ??????? ???"        
  },
  {
    "name": "description",
    "value": "????? ??????? ??? ??? ?? ???? ?????"
  },
  {
    "name": "created",
    "value": "1504079823857"
  },
  {
    "name": "updated",
    "value": "1504079836355"
  },
  {
    "name": "updaterName",
    "value": "v.sabeti"
  },
  {
    "name": "updaterFullName",
    "value": "???? ?????"
  },
  {
    "name": "reporterName",
    "value": "v.sabeti"
  },
  {
    "name": "reporterFullName",
    "value": "???? ?????"
  },
  {
    "name": "commentsCount",
    "value": "0"
  },
  {
    "name": "votes",
    "value": "0"
  },
  {
    "name": "Priority",
    "value": [
      "Normal"
    ],
    "valueId": [
      "Normal"
    ],
    "color": {
      "bg": "#e6f6cf",
      "fg": "#4da400"
    }
  },
  {
    "name": "Type",
    "value": [
      "Task"
    ],
    "valueId": [
      "Task"
    ],
    "color": null
  },
  {
    "name": "State",
    "value": [
      "Open"
    ],
    "valueId": [
      "Open"
    ],
    "color": null
  },
  {
    "name": "Assignee",
    "value": [
      {
        "value": "a.fathizade",
        "fullName": "Ali Fathizadeh"
      }
    ]
  },
  {
    "name": "Subsystem",
    "value": [
      "Employees"
    ],
    "valueId": [
      "Employees"
    ],
    "color": {
      "bg": "#ff7123",
      "fg": "#fff"
    }
  },
  {
    "name": "sprint",
    "value": [
      {
        "value": "First sprint",
        "id": "Etc Board:First sprint"
      }
    ]
  }
],
"comment": [],
"tag": []
 },
{
"id": "ETC-7",
"entityId": "94-5036",
"jiraId": null,
"field": [
  {
    "name": "projectShortName",
    "value": "ETC"
  },
  {
    "name": "numberInProject",
    "value": "7"
  },
  {
    "name": "summary",
    "value": "????????? ?? ????? ?????? ? ????? ?? ?? ??? ??????"
  },
  {
    "name": "created",
    "value": "1504079868785"
  },
  {
    "name": "updated",
    "value": "1504079868785"
  },
  {
    "name": "updaterName",
    "value": "v.sabeti"
  },
  {
    "name": "updaterFullName",
    "value": "???? ?????"
  },
  {
    "name": "reporterName",
    "value": "v.sabeti"
  },
  {
    "name": "reporterFullName",
    "value": "???? ?????"
  },
  {
    "name": "commentsCount",
    "value": "0"
  },
  {
    "name": "votes",
    "value": "0"
  },
  {
    "name": "Priority",
    "value": [
      "Normal"
    ],
    "valueId": [
      "Normal"
    ],
    "color": {
      "bg": "#e6f6cf",
      "fg": "#4da400"
    }
  },
  {
    "name": "Type",
    "value": [
      "Task"
    ],
    "valueId": [
      "Task"
    ],
    "color": null
  },
  {
    "name": "State",
    "value": [
      "Open"
    ],
    "valueId": [
      "Open"
    ],
    "color": null
  },
  {
    "name": "Assignee",
    "value": [
      {
        "value": "a.fathizade",
        "fullName": "Ali Fathizadeh"
      }
    ]
    },
    {
    "name": "Subsystem",
    "value": [
      "Employees"
    ],
    "valueId": [
      "Employees"
    ],
    "color": {
      "bg": "#ff7123",
      "fg": "#fff"
    }
  },
  {
    "name": "sprint",
    "value": [
      {
        "value": "First sprint",
        "id": "Etc Board:First sprint"
      }
    ]
  }
],
"comment": [],
"tag": []
}
]

这是我为json: Issues编写的类：

@JsonIgnoreProperties(ignoreUnknown = true)
@JsonInclude(JsonInclude.Include.NON_NULL)
public class Issues implements Serializable
{
@JsonProperty
private Issue[] issue;

public Issue[] getIssue ()
{
    return issue;
}

public void setIssue (Issue[] issue)
{
    this.issue = issue;
}

@Override
public String toString()
{
    return "ClassPojo [issue = "+issue+"]";
}
}

问题：

@JsonIgnoreProperties(ignoreUnknown = true)
@JsonInclude(JsonInclude.Include.NON_NULL)
public class Issue implements Serializable
{

@JsonProperty
private String id;

@JsonProperty
private Field [] field;

public String getId() {
    return id;
}

public void setId(String id) {
    this.id = id;
}

public Field[] getField() {
    return field;
}

public void setField(Field[] field) {
    this.field = field;
}

@Override
public String toString() {
    return "Issue{" +
            "id='" + id + '\'' +
            ", field=" + Arrays.toString(field) +
            '}';
 }
 }

字段：

@JsonIgnoreProperties(ignoreUnknown = true)
@JsonInclude(JsonInclude.Include.NON_NULL)
public class Field implements Serializable {


@JsonProperty
private String name;


public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}


@Override
public String toString() {
    return "Field{" +
            "name='" + name + '\'' +
//                ", value='" + value + '\'' +
            '}';
}
}

Answer 1

因为您的“根”实体是一种数组(正如异常消息所说的那样)，(据我所知) Jackson Mapper使用从Collection继承的方法。因此，最快、最简单的方法是从集合实现继承方法，例如ArrayList：

...
public class Issues extends ArrayList<Issue> {

@Override
public String toString() {
    return "ClassPojo [issue = " + super.toString() +  "]";
 }

}

请注意，您不再需要"issue“属性，该数组由List实现在内部存储。上面的示例适用于我，它是从com.fasterxml.jackson.databind.ObjectMapper调用的( getJson()返回您提供的字符串)：

ObjectMapper mapperObj = new ObjectMapper();
    try {
        Issues li = mapperObj.readValue(getJson(),Issues.class);
        System.out.println(li);
    } catch (IOException e) {
        e.printStackTrace();
    }

输出：

ClassPojo [issue = [Issue{id='ETC-1', field=[Field{name='projectShortName'}, Field{name='numberInProject'}, Field{name='summary'}, Field{name='created'}, Field{name='updated'}, Field{name='updaterName'}, Field{name='updaterFullName'}, Field{name='resolved'}, Field{name='reporterName'}, Field{name='reporterFullName'}, Field{name='commentsCount'}, Field{name='votes'}, Field{name='Priority'}, Field{name='Type'}, Field{name='State'}, Field{name='Assignee'}, Field{name='Subsystem'}, Field{name='sprint'}]}, Issue{id='ETC-2', field=[Field{name='projectShortName'}, Field{name='numberInProject'}, Field{name='summary'}, Field{name='created'}, Field{name='updated'}, Field{name='updaterName'}, Field{name='updaterFullName'}, Field{name='resolved'}, Field{name='reporterName'}, Field{name='reporterFullName'}, Field{name='commentsCount'}, Field{name='votes'}, Field{name='Priority'}, Field{name='Type'}, Field{name='State'}, Field{name='Assignee'}, Field{name='Subsystem'}, Field{name='sprint'}]}, Issue{id='ETC-4', field=[Field{name='projectShortName'}, Field{name='numberInProject'}, Field{name='summary'}, Field{name='created'}, Field{name='updated'}, Field{name='updaterName'}, Field{name='updaterFullName'}, Field{name='reporterName'}, Field{name='reporterFullName'}, Field{name='commentsCount'}, Field{name='votes'}, Field{name='Priority'}, Field{name='Type'}, Field{name='State'}, Field{name='Assignee'}, Field{name='Subsystem'}, Field{name='sprint'}]}, Issue{id='ETC-5', field=[Field{name='projectShortName'}, Field{name='numberInProject'}, Field{name='summary'}, Field{name='created'}, Field{name='updated'}, Field{name='updaterName'}, Field{name='updaterFullName'}, Field{name='resolved'}, Field{name='reporterName'}, Field{name='reporterFullName'}, Field{name='commentsCount'}, Field{name='votes'}, Field{name='Priority'}, Field{name='Type'}, Field{name='State'}, Field{name='Assignee'}, Field{name='Subsystem'}, Field{name='sprint'}]}, Issue{id='ETC-6', field=[Field{name='projectShortName'}, Field{name='numberInProject'}, Field{name='summary'}, Field{name='description'}, Field{name='created'}, Field{name='updated'}, Field{name='updaterName'}, Field{name='updaterFullName'}, Field{name='reporterName'}, Field{name='reporterFullName'}, Field{name='commentsCount'}, Field{name='votes'}, Field{name='Priority'}, Field{name='Type'}, Field{name='State'}, Field{name='Assignee'}, Field{name='Subsystem'}, Field{name='sprint'}]}, Issue{id='ETC-7', field=[Field{name='projectShortName'}, Field{name='numberInProject'}, Field{name='summary'}, Field{name='created'}, Field{name='updated'}, Field{name='updaterName'}, Field{name='updaterFullName'}, Field{name='reporterName'}, Field{name='reporterFullName'}, Field{name='commentsCount'}, Field{name='votes'}, Field{name='Priority'}, Field{name='Type'}, Field{name='State'}, Field{name='Assignee'}, Field{name='Subsystem'}, Field{name='sprint'}]}]]