오류 : com.fasterxml.jackson.databind.JsonMappingException : serializer가 없습니다.

Question

getqueryResults로 bigquery 작업에서 List를 가져오고 있으며 JSON으로의 변환이 실패한 것 같습니다. 내가 this을 발견했습니다 다음과 같이 주석 그것을 시도 : 성공하지

@JsonAutoDetect(fieldVisibility = Visibility.ANY) 

비록. 여기

코드의 조각 :

import java.io.IOException; 
import java.util.ArrayList; 
import java.util.List; 
import com.fasterxml.jackson.annotation.JsonAutoDetect; 
import com.google.api.client.googleapis.auth.oauth2.GoogleCredential; 
import com.google.api.client.http.HttpTransport; 
import com.google.api.client.http.javanet.NetHttpTransport; 
import com.google.api.client.json.JsonFactory; 
import com.google.api.client.json.jackson2.JacksonFactory; 
import com.google.api.services.bigquery.Bigquery; 
import com.google.api.services.bigquery.BigqueryScopes; 
import com.google.api.services.bigquery.model.*; 

@JsonAutoDetect(fieldVisibility = JsonAutoDetect.Visibility.ANY) 

public class Query { 
    private String id; 
    private String sql; 
    private List<TableRow> results; 

    private static Bigquery createAuthorizedClient() throws IOException { 
     HttpTransport transport = new NetHttpTransport(); 
     JsonFactory jsonFactory = new JacksonFactory(); 
     GoogleCredential credential = GoogleCredential.getApplicationDefault(transport, jsonFactory); 
     // Depending on the environment that provides the default credentials (e.g. Compute Engine, App 
     // Engine), the credentials may require us to specify the scopes we need explicitly. 
     // Check for this case, and inject the Bigquery scope if required. 
     if (credential.createScopedRequired()) { 
      credential = credential.createScoped(BigqueryScopes.all()); 
     } 

     return new Bigquery.Builder(transport, jsonFactory, credential).setApplicationName(" ...OMITTED... ").build(); 
    } 

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

    public String getSql() { return this.sql; } 
    public void setSql(String sql) { this.sql = sql;} 

    public List<TableRow> getResults() { return this.results; } 
    public void setResults(List<TableRow> r) { this.results = r; } 

    public void update() { 
     this.results = new ArrayList<TableRow>(); 
     if (!this.sql.isEmpty()){ 
      try { 
       Bigquery bq = createAuthorizedClient(); 
       this.results = executeQuery(bq, this.sql); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } 
     } 
    } 

    private List<TableRow> executeQuery(Bigquery bq, String querySql) throws IOException { 
     QueryResponse query = bq.jobs().query(" ...OMITTED... ", new QueryRequest().setQuery(querySql)).execute(); 

     // Execute it 
     GetQueryResultsResponse queryResult = bq.jobs() 
       .getQueryResults(query.getJobReference().getProjectId(), query.getJobReference().getJobId()).execute(); 

     List<TableRow> rows = queryResult.getRows(); 
     return rows; 
    } 

내가 주석에 익숙하지 그리고 난 BigQuery에서이 JSON 변환에서 응답을 얻는 방법을 모른다, 누군가가 도와 드릴까요?

Answer 1

당신은 ... 당신의 자신의 JSON 개체를 구축해야

public void update() { 
    String r = "{\"rows\": ["; 
    List<TableRow> bqresults; 
    if (!this.sql.isEmpty()){ 
     try { 
      Bigquery bq = createAuthorizedClient(); 
      bqresults = executeQuery(bq, this.sql); 
      int rowIx = 0; 
      int rowMax = bqresults.size() - 1; 
      for(TableRow row : bqresults) { 
       r += row.toString(); 
       rowIx++; 
       if (rowIx <= rowMax) r += ","; 
      } 
      r += "]}"; 
      this.results = r; 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 
}