線程“主”java.lang.NoSuchFieldError 中的異常：實例

Question

我正在嘗試使用 HTTPClient 編寫一個簡單的 WebService 測試。 我已經加載了所有的罐子，但收到了上述錯誤消息。

為什么我會收到此錯誤消息？

這是代碼：

package HTTPClientTest;

import java.io.IOException;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.impl.client.HttpClientBuilder;
import org.junit.Assert;


public class RESTTester {

    public static void main (String args[]) {

    String restURL_XML = "http://parabank.parasoft.com/parabank/services/bank/customers/12212/";


    try {

    testStatusCode(restURL_XML);

    } catch (ClientProtocolException e) {

    e.printStackTrace();
    } catch (IOException e) {
    e.printStackTrace();
    } 
}


public static void testStatusCode(String restURL) throws ClientProtocolException, IOException {
    HttpUriRequest request = new HttpGet(restURL);
    HttpResponse httpResponse = HttpClientBuilder.create().build().execute(request);
    Assert.assertEquals(httpResponse.getStatusLine().getStatusCode(),HttpStatus.SC_OK);
    }

}

下面是錯誤堆棧跟蹤，

Exception in thread "main" java.lang.NoSuchFieldError: INSTANCE
    at org.apache.http.conn.ssl.SSLConnectionSocketFactory.<clinit>(SSLConnectionSocketFactory.java:144)
    at org.apache.http.impl.client.HttpClientBuilder.build(HttpClientBuilder.java:966)
    at HTTPClientTest.RESTTester.testStatusCode(RESTTester.java:37)
    at HTTPClientTest.RESTTester.main(RESTTester.java:22)

Answer 1

我收到上述錯誤是因為我的項目中有多個舊版本的 HTTPClient。 我刪除了舊版本的 HTTPClient，現在錯誤消息消失了。

Answer 2

通過分析你的堆棧跟蹤，我發現你的程序寫得很好。 似乎 apache HTTP API 編譯錯誤。 也許包org.apache.http.impl.client是針對與您使用的不同版本的org.apache.http.conn.ssl編譯的？ 將這兩個軟件包升級到最新版本並重試。 將其報告給 HTTPClient 錯誤跟蹤器。

Answer 3

我ve come across this error(java.lang.NoSuchFieldError: INSTANCE) several times. With different reasons here it is INSTANCE. This error is conveying about the mismatch between the aws-java-sdk-core library and one of the service-specific SDK ve come across this error(java.lang.NoSuchFieldError: INSTANCE) several times. With different reasons here it is INSTANCE. This error is conveying about the mismatch between the aws-java-sdk-core library and one of the service-specific SDK ve come across this error(java.lang.NoSuchFieldError: INSTANCE) several times. With different reasons here it is INSTANCE. This error is conveying about the mismatch between the aws-java-sdk-core library and one of the service-specific SDK s aws-sdk-s3 或 aws-java-sdk-sqs 之一不匹配。

我在將 aws-java-sdk-core(1.11.289) 與 aws-sdk-s3(1.11.428) 一起使用時遇到了這個錯誤。 通過將以下 aws-java-sdk-core(1.11.289) 與 aws-sdk-s3(1.11.186) 一起使用來修復它。