HttpClientBuilder - java.lang.NoSuchFieldError：INSTANCE [英] HttpClientBuilder - java.lang.NoSuchFieldError: INSTANCE

问题描述

我有一个使用HttpClient执行HTTP请求的Maven Java项目。在我的本地Java Web Server上，一切正常。但在我将其部署到SAP Hana Cloud Platform后，我收到以下错误：

I have a Maven Java project that uses an HttpClient to execute HTTP requests. On my local Java Web Server everything works fine. But after I deploy it to the SAP Hana Cloud Platform I get the following error:

java.lang.NoSuchFieldError: INSTANCE
at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.<init>(DefaultHttpRequestWriterFactory.java:52)
at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.<init>(DefaultHttpRequestWriterFactory.java:56)
at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.<clinit>(DefaultHttpRequestWriterFactory.java:46)
at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.<init>(ManagedHttpClientConnectionFactory.java:72)
at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.<init>(ManagedHttpClientConnectionFactory.java:84)
at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.<clinit>(ManagedHttpClientConnectionFactory.java:59)
at org.apache.http.impl.conn.PoolingHttpClientConnectionManager$InternalConnectionFactory.<init>(PoolingHttpClientConnectionManager.java:493)
at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.<init>(PoolingHttpClientConnectionManager.java:149)
at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.<init>(PoolingHttpClientConnectionManager.java:138)
at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.<init>(PoolingHttpClientConnectionManager.java:114)
at org.apache.http.impl.client.HttpClientBuilder.build(HttpClientBuilder.java:726)
at com.sap.hana.cloud.odata.service.OlingoSampleApp.getHttpclient(OlingoSampleApp.java:382)
at com.sap.hana.cloud.odata.service.OlingoSampleApp.getCsrfToken(OlingoSampleApp.java:374)
at com.sap.hana.cloud.odata.service.ODataCalls.doGet(ODataCalls.java:163)
...

我的依赖关系如下：

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.3.5</version>
    <scope>compile</scope>
</dependency>

根据这个问题 Java应用程序中的Mashape Unirest的java.lang.NoSuchFieldError：org.apache.http.message.BasicLineFormatter.INSTANCE 我试过用以下代码获取ClassLoader Ressource。

According to this question java.lang.NoSuchFieldError: org.apache.http.message.BasicLineFormatter.INSTANCE from Mashape Unirest in Java application I tried to use the following code to get the ClassLoader Ressource.

ClassLoader classLoader = this.getClass().getClassLoader();
URL resource = classLoader.getResource("org/apache/http/impl/client/HttpClientBuilder.class");
return resource;

并返回以下内容

"jar:file:/some/path/WEB-INF/lib/httpclient-4.3.5.jar!/org/apache/http/impl/client/HttpClientBuilder.class"

您可以看到jar版本是相同的。我看到的每个类似的问题都有不连贯的jar版本作为失败的根源。这个错误还有其他原因吗？

You can see that the jar-versions are the same. Every similar question I looked at had incoherent jar-versions as the source of failure. Could there be another reason for this error?

更新

讨论后在评论中我将更新我的问题：

After the discussion in the comments I'll update my question:

依赖树：

所以现在我看到版本冲突了，我删除了新Java的Web-API 。 classLoader现在再次返回版本4.3.2。但我仍然从一开始就得到错误。

So now I could see the version conflict and I removed the neo-java-web-api. The classLoader now returns version 4.3.2 again. But I still get the error from the beginning.

现在，没有 neo-java-web-api 的新的完整依赖关系树如下所示：

The new, complete dependency tree without the neo-java-web-api now looks like the following:

推荐答案

我仍然无法找到实际问题的解决方案。但至少我可以找到一个解决方法。我将范围更改为< scope>提供< / scope> 并仅使用版本4.1.4中提供的函数。例如 new DefaultHttpClient（cm）; 而不是 HttpClientBuilder.create（）。build（）;

I still couldn't find a solution for the actual problem. But at least I could find a workaround. I changed the scope to <scope>provided</scope> and only use functions, which are also available in version 4.1.4. For example new DefaultHttpClient(cm); instead of HttpClientBuilder.create().build();

这篇关于HttpClientBuilder - java.lang.NoSuchFieldError：INSTANCE的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！