尝试使用Java中的Google电子表格API读取数据时获取nullpointer异常。创建了电子表格并启用了Google Spreadsheet API。还下载了client_services.json文件并添加到src / resources / path中。在运行时仍然会出现nullpointer异常。
package main.java;
import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.extensions.java6.auth.oauth2.AuthorizationCodeInstalledApp;
import com.google.api.client.extensions.jetty.auth.oauth2.LocalServerReceiver;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.util.store.FileDataStoreFactory;
import com.google.api.services.sheets.v4.SheetsScopes;
import com.google.api.services.sheets.v4.model.*;
import com.google.api.services.sheets.v4.Sheets;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.List;
public class Quickstart {
/** Application name. */
private static final String APPLICATION_NAME =
"Google Sheets API Java Quickstart";
/** Directory to store user credentials for this application. */
private static final java.io.File DATA_STORE_DIR = new java.io.File(
System.getProperty("user.home"), ".credentials/sheets.googleapis.com-java-quickstart");
/** Global instance of the {@link FileDataStoreFactory}. */
private static FileDataStoreFactory DATA_STORE_FACTORY;
/** Global instance of the JSON factory. */
private static final JsonFactory JSON_FACTORY =
JacksonFactory.getDefaultInstance();
/** Global instance of the HTTP transport. */
private static HttpTransport HTTP_TRANSPORT;
/** Global instance of the scopes required by this quickstart.
*
* If modifying these scopes, delete your previously saved credentials
* at ~/.credentials/sheets.googleapis.com-java-quickstart
*/
private static final List<String> SCOPES =
Arrays.asList(SheetsScopes.SPREADSHEETS_READONLY);
static {
try {
HTTP_TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
DATA_STORE_FACTORY = new FileDataStoreFactory(DATA_STORE_DIR);
} catch (Throwable t) {
t.printStackTrace();
System.exit(1);
}
}
/**
* Creates an authorized Credential object.
* @return an authorized Credential object.
* @throws IOException
*/
public static Credential authorize() throws IOException {
// Load client secrets.
InputStream in =
Quickstart.class.getResourceAsStream("//client_secret.json");
GoogleClientSecrets clientSecrets =
GoogleClientSecrets.load(JSON_FACTORY, new InputStreamReader(in));
// Build flow and trigger user authorization request.
GoogleAuthorizationCodeFlow flow =
new GoogleAuthorizationCodeFlow.Builder(
HTTP_TRANSPORT, JSON_FACTORY, clientSecrets, SCOPES)
.setDataStoreFactory(DATA_STORE_FACTORY)
.setAccessType("offline")
.build();
Credential credential = new AuthorizationCodeInstalledApp(
flow, new LocalServerReceiver()).authorize("user");
System.out.println(
"Credentials saved to " + DATA_STORE_DIR.getAbsolutePath());
return credential;
}
/**
* Build and return an authorized Sheets API client service.
* @return an authorized Sheets API client service
* @throws IOException
*/
public static Sheets getSheetsService() throws IOException {
Credential credential = authorize();
return new Sheets.Builder(HTTP_TRANSPORT, JSON_FACTORY, credential)
.setApplicationName(APPLICATION_NAME)
.build();
}
public static void main(String[] args) throws IOException {
// Build a new authorized API client service.
Sheets service = getSheetsService();
// https://docs.google.com/spreadsheets/d/1BxiMVs0XRA5nFMdKvBdBZjgmUUqptlbs74OgvE2upms/edit
String spreadsheetId = "12tEQZqb-12N-a8hF-4TG-1E0qqJuhrYTl5CYAeIg0Sc";
String range = "Sheet1!A1:E";
ValueRange response = service.spreadsheets().values()
.get(spreadsheetId, range)
.execute();
List<List<Object>> values = response.getValues();
if (values == null || values.size() == 0) {
System.out.println("No data found.");
} else {
for (List row : values) {
// Print columns A and E, which correspond to indices 0 and 4.
System.out.printf("%s, %s\n", row.get(0), row.get(4));
}
}
}
}
另外，添加了＆＃34; client_secret.json＆＃34;文件在src / main / resources / path中。 这是痕迹。想知道为什么即使在client_secret文件有数据之后它也显示为null。想知道即使client_secret有正确的数据，它显示为null的正当理由。它也被添加到正确的路径中。
> java.lang.NullPointerException
at java.io.Reader.<init>(Reader.java:78)
at java.io.InputStreamReader.<init>(InputStreamReader.java:72)
at main.java.Quickstart.authorize(Quickstart.java:73)
at main.java.Quickstart.getSheetsService(Quickstart.java:102)
at main.java.Quickstart.main(Quickstart.java:110)
Exception in thread "main" com.google.api.client.googleapis.json.GoogleJsonResponseException: 403 Forbidden
{
"code" : 403,
"errors" : [ {
"domain" : "global",
"message" : "The request is missing a valid API key.",
"reason" : "forbidden"
} ],
"message" : "The request is missing a valid API key.",
"status" : "PERMISSION_DENIED"
}
at com.google.api.client.googleapis.json.GoogleJsonResponseException.from(GoogleJsonResponseException.java:146)
at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:113)
at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:40)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest$1.interceptResponse(AbstractGoogleClientRequest.java:321)
at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:1065)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:419)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:352)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.execute(AbstractGoogleClientRequest.java:469)
at main.java.Quickstart.main(Quickstart.java:118)