解决Jackson解析嵌套类问题(MismatchedInputException)

Jackson解析嵌套类(MismatchedInputException)

具体报错如下

问题描述：Jackson解析嵌套类问题 

调用接口返回json格式的数据，使用Jackson解析参数转换成对象：

@Data
@JsonIgnoreProperties(ignoreUnknown = true)
public class PixlIdDto implements Serializable {

@JsonIgnore
   private static final long serialVersionUID = -5776690969534186379L;

@JsonProperty("models")
   private List<Models> models;

@Data
   @JsonIgnoreProperties(ignoreUnknown = true)
   public class Models implements Serializable {

@JsonIgnore
       private static final long serialVersionUID = 9189184337502771734L;

@JsonProperty("medias")
       private List<Medias> medias;

@JsonProperty("code")
       private String code;
       @Data
       @JsonIgnoreProperties(ignoreUnknown = true)
       public class Medias implements Serializable {

@JsonIgnore
           private static final long serialVersionUID = 136346277159168673L;

@JsonProperty("mediaZones")
           private List<MediaZones> mediaZones;
           @Data
           @JsonIgnoreProperties(ignoreUnknown = true)
           public class MediaZones implements Serializable {

@JsonIgnore
               private static final long serialVersionUID = 7683892920280290206L;

@JsonProperty("medias")
               private List<MediasInner> medias;

@JsonProperty("name")
               private String name;
               @Data
               @JsonIgnoreProperties(ignoreUnknown = true)
               public class MediasInner implements Serializable {

@JsonIgnore
                   private static final long serialVersionUID = 8653771742539974404L;

@JsonProperty("displayOrder")
                   private int displayOrder ;

@JsonProperty("pixlId")
                   private String pixlId;
               }
           }
       }
   }
}

问题本质为：内部非静态类无法实例化

你需要做两件事：

• 给内部类前面加上static

• 给内部类加上默认构造函数

改过后的内部类像这样：

@Data
@JsonIgnoreProperties(ignoreUnknown = true)
public class PixlIdDto implements Serializable {

@JsonIgnore
   private static final long serialVersionUID = -5776690969534186379L;

@JsonProperty("models")
   private List<Models> models;

@Data
   @JsonIgnoreProperties(ignoreUnknown = true)
   @NoArgsConstructor
   public static class Models implements Serializable {

@JsonIgnore
       private static final long serialVersionUID = 9189184337502771734L;

@JsonProperty("medias")
       private List<Medias> medias;

@JsonProperty("code")
       private String code;

@Data
       @JsonIgnoreProperties(ignoreUnknown = true)
       @NoArgsConstructor
       public static class Medias implements Serializable {

@JsonIgnore
           private static final long serialVersionUID = 136346277159168673L;

@JsonProperty("mediaZones")
           private List<MediaZones> mediaZones;

@Data
           @JsonIgnoreProperties(ignoreUnknown = true)
           @NoArgsConstructor
           public static class MediaZones implements Serializable {

@JsonIgnore
               private static final long serialVersionUID = 7683892920280290206L;

@JsonProperty("medias")
               private List<MediasInner> medias;

@JsonProperty("name")
               private String name;

@Data
               @JsonIgnoreProperties(ignoreUnknown = true)
               @NoArgsConstructor
               public static class MediasInner implements Serializable {

@JsonIgnore
                   private static final long serialVersionUID = 8653771742539974404L;

@JsonProperty("displayOrder")
                   private int displayOrder;

@JsonProperty("pixlId")
                   private String pixlId;
               }
           }
       }
   }
}

问题完美解决。

Jackson处理嵌套Json数据

数据 ------》打印每条数据

{
 "ID": 10001,
 "detail": "detail",
 "json_format_version": 1.0,
 "other_info": {
   "array_one": [
     [855, 410],
     [854, 411],
     [847, 411],
     [846, 410],
     [845, 410],
     [844, 409]
   ],
   "array_two": [
     [832, 303],
     [829, 303],
     [828, 302],
     [825, 302],
     [824, 301]
   ],
   "array_three": [
     [1013, 224],
     [1012, 225],
     [1010, 225],
     [1009, 226],
     [1023, 224]
   ],
   "point": [853, 310],
   "boolean": true
 }
}

代码

public class Test {
   public static void main(String[] args) throws IOException {
//        File file = new File("src/main/resources/doc/windABC.json");
//        FileInputStream fip = new FileInputStream(file);
       BufferedReader br = new BufferedReader(new FileReader("src/main/resources/doc/resource.json"));
       ObjectMapper mapper = new ObjectMapper();
       //读取json的节点
       JsonNode node = mapper.readTree(br);
       //获取所有的key
       Iterator<String> keys = node.fieldNames();

BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter("src/main/resources/doc/result.txt"));
       bufferedWriter.write("项目：**********\t\t");
       bufferedWriter.write("部门：**********\t\t");
       bufferedWriter.write("工号：**********\n");

while (keys.hasNext()) {
           String key = keys.next();
           bufferedWriter.write(key + ":");
           bufferedWriter.newLine();
           if (key.equals("other_info")) {
               JsonNode other_infoNode = mapper.readTree(node.get(key).toString());
               Iterator<String> other_info_Key = other_infoNode.fieldNames();
               for (JsonNode jsonNode : other_infoNode) {
                   bufferedWriter.write(other_info_Key.next().toString()  + ":\n");
                   isArrayNode(jsonNode,mapper,bufferedWriter);
               }
           } else {
               bufferedWriter.write(node.get(key).asText());
               bufferedWriter.newLine();
           }
           bufferedWriter.newLine();

}
       bufferedWriter.close();
       br.close();
   }

public static void isArrayNode(JsonNode jsonNode,ObjectMapper mapper,BufferedWriter bufferedWriter) throws IOException {
       if (jsonNode.isArray()) {
           for (JsonNode node1 : jsonNode) {
               isArrayNode(node1,mapper,bufferedWriter);//递归调用，判断是否数组嵌套数组
           }
           bufferedWriter.newLine();
       }else {
          bufferedWriter.write(jsonNode.asText());
          bufferedWriter.newLine();
       }
   }
}

输出结果

项目：********        部门：********        工号：********
ID:
10001

detail:
detail

json_format_version:
1.0

other_info:
array_one:
855
410

854
411

847
411

846
410

845
410

844
409

array_two:
832
303

829
303

828
302

825
302

824
301

array_three:
1013
224

1012
225

1010
225

1009
226

1023
224

point:
853
310

boolean:
true

来源：https://blog.csdn.net/weixin_40910372/article/details/100669444