将字段解析为对象或数组时出错

Question

我有以下Json字符串，我想要反序列化。问题是：因为这个字符串来自服务器我不能改变它，我需要反序列化为POJO。你可以看到Grafs键对每个分区都有不同的值。一个是一个对象，另一个是数组。我该如何处理？

{ 
"Status": "true", 
"Result: { 
    "rows": { 
     "row": { 
      "status": true, 
      "subareas": [ 
       { 
        "nome": "Associacao Utente", 
        "id": 9, 
        "grafs": { 
         "rows": { 
          "id": 6, 
          "nome": "Associacao Utente", 
          "tipo": "PIE", 
          "serv": "MV_AS_UTENTE_POR_NEGOCIO", 
          "periodo": "ANO" 
         } 
        } 
       }, { 
        "nome": "Chaves", 
        "id": 60, 
        "grafs": { 
         "rows": [ 
          { 
           "id": 35, 
           "nome": "Chaves Criados por ano", 
           "tipo": "LINHA", 
           "serv": "MV_ASSOC_TOTAL_CHAVES", 
           "periodo": "ANO" 
          }, { 
           "id": 592, 
           "nome": "Chaves Associado Ao User Portal", 
           "tipo": "BAR", 
           "serv": "MV_ASSOC_USER_CHAVES", 
           "periodo": "TODOS" 
          }, { 
           "id": 593, 
           "nome": "Chaves Associado Ao Negocios", 
           "tipo": "BAR", 
           "serv": "MV_ASSOC_CHAVES", 
           "periodo": "TODOS" 
          } 
         ] 
        } 
       } 
      ] 
     } 
    } 
} 

}

这里紧跟我的班。

public class Example { 
    private String Status; 
    private Result Result; 

    public String getStatus() { 
     return Status; 
    } 

    public void setStatus(String status) { 
     Status = status; 
    } 

    public Result getResult() { 
     return Result; 
    } 

    public void setResult(Result result) { 
     Result = result; 
    } 

    @Override 
    public String toString() { 
     return "Example [Status=" + Status + ", Result=" + Result + "]"; 
    } 

} 

public class Result { 
    private Rows rows; 

    public Rows getRows() { 
     return rows; 
    } 

    public void setRows(Rows rows) { 
     this.rows = rows; 
    } 

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

public class Grafs { 
    private List<Rows_> rows = new ArrayList<>(); 

    public List<Rows_> getRows() { 

     return rows; 
    } 

    public void setRows(List<Rows_> Rows) { 
     this.rows = Rows; 
    } 


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

public class Row { 
    private Boolean status; 
    private List<Subarea> subareas = new ArrayList<>(); 

    public Boolean getStatus() { 
     return status; 
    } 

    public void setStatus(Boolean status) { 
     this.status = status; 
    } 

    public List<Subarea> getSubareas() { 
     return subareas; 
    } 

    public void setSubareas(List<Subarea> subareas) { 
     this.subareas = subareas; 
    } 

    @Override 
    public String toString() { 
     return "Row [status=" + status + ", subareas=" + subareas + "]"; 
    } 
} 

public class Row_ { 
    private Integer id; 
    private String nome; 
    private String serv; 
    private String periodo; 

    public Integer getId() { 
     return id; 
    } 

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

    public String getNome() { 
     return nome; 
    } 

    public void setNome(String nome) { 
     this.nome = nome; 
    } 

    public String getServ() { 
     return serv; 
    } 

    public void setServ(String serv) { 
     this.serv = serv; 
    } 

    public String getPeriodo() { 
     return periodo; 
    } 

    public void setPeriodo(String periodo) { 
     this.periodo = periodo; 
    } 

    @Override 
    public String toString() { 
     return "Row_ [id=" + id + ", nome=" + nome + ", serv=" + serv 
       + ", periodo=" + periodo + "]"; 
    } 
} 

public class Rows { 
    private Row row; 

    public Row getRow() { 
     return row; 
    } 

    public void setRow(Row row) { 
     this.row = row; 
    } 

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

public class Rows_ { 
    private Row_ row; 

    public Row_ getRow() { 
     return row; 
    } 

    public void setRow(Row_ row) { 
     this.row = row; 
    } 
} 

public class Subarea { 
    private String nome; 
    private Integer id; 

    private Grafs grafs; 

    public String getNome() { 
     return nome; 
    } 

    public void setNome(String nome) { 
     this.nome = nome; 
    } 

    public Integer getId() { 
     return id; 
    } 

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

    public Grafs getGrafs() { 
     return grafs; 
    } 

    public void setGrafs(Grafs grafs) { 
     this.grafs = grafs; 
    } 

    @Override 
    public String toString() { 
     return "Subarea [nome=" + nome + ", id=" + id + ", grafs=" + grafs 
       + "]"; 
    } 
} 

使用这些类，我发现了以下错误：

Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 13 column 18. 

我宣布Rows_作为ArrayList和它遇到的物体来代替。但第二行ROW确实是一个数组。我如何解决这个问题？

具有一个元素的数组仍应呈现为数组。这就是我使用数组的原因。但它给了我描述的错误。

感谢您的帮助。对此，我真的非常感激。

Answer 1

您可以使用TypeAdapterFactory来进行转换。这里是一个工厂，这将是功能添加到您所有的List成员类型 -

import com.google.gson.Gson; 
import com.google.gson.TypeAdapter; 
import com.google.gson.TypeAdapterFactory; 
import com.google.gson.reflect.TypeToken; 
import com.google.gson.stream.JsonReader; 
import com.google.gson.stream.JsonToken; 
import com.google.gson.stream.JsonWriter; 
import java.io.IOException; 
import java.lang.reflect.ParameterizedType; 
import java.lang.reflect.Type; 
import java.util.Collections; 
import java.util.List; 

public class SingletonListTypeAdapterFactory implements TypeAdapterFactory { 
    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) { 

     Type type = typeToken.getType(); 
     if (typeToken.getRawType() != List.class 
      || !(type instanceof ParameterizedType)) { 
     return null; 
     } 
     Type elementType = ((ParameterizedType) type).getActualTypeArguments()[0]; 
     TypeAdapter<?> elementAdapter = gson.getAdapter(TypeToken.get(elementType)); 
     TypeAdapter<T> arrayAdapter = gson.getDelegateAdapter(this, typeToken); 
     return (TypeAdapter<T>) newSingtonListAdapter((TypeAdapter<Object>) elementAdapter, (TypeAdapter<List<Object>>) arrayAdapter); 
    } 

    private <E> TypeAdapter<List<E>> newSingtonListAdapter(
     final TypeAdapter<E> elementAdapter, 
     final TypeAdapter<List<E>> arrayAdapter) { 
     return new TypeAdapter<List<E>>() { 

     public void write(JsonWriter out, List<E> value) throws IOException { 
      if(value == null || value.isEmpty()) { 
      out.nullValue(); 
      } else if(value.size() == 1) { 
      elementAdapter.write(out, value.get(0)); 
      } else { 
      arrayAdapter.write(out, value); 
      } 
     } 

     public List<E> read(JsonReader in) throws IOException { 
      if (in.peek() != JsonToken.BEGIN_ARRAY) { 
      E obj = elementAdapter.read(in); 
      return Collections.singletonList(obj); 
      } 
      return arrayAdapter.read(in); 
     } 
     }; 
    } 
    } 

至于奖金，这也序列化​​以同样的方式，如果需要的话。如果您还想序列化为阵列，请将write方法替换为arrayAdapter.write的调用。

为了你，当构建添加到您的GSON -

Gson gson = new GsonBuilder().registerTypeAdapterFactory(new SingletonListTypeAdapterFactory()) 
     .create();