java.lang.NoClassDefFoundError: Failed resolution of: Lorg/apache/commons/logging/LogFactory 错误解决方案

环境: Android Studio 4.1.2

记录一次简单的出包过程遇到的问题。接入小米的sdk的时候，遇到crash，查看日志发现

    --------- beginning of crash
2021-01-29 15:18:06.435 28062-29203/? E/AndroidRuntime: FATAL EXCEPTION: Thread-18
    Process: cn.xxxxxx.xxx.mi, PID: 28062
    java.lang.NoClassDefFoundError: Failed resolution of: Lorg/apache/commons/logging/LogFactory;
        at org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager.<init>(ThreadSafeClientConnManager.java:155)
        at com.xxxxxx.sdk.tools.HttpTools.getNewHttpClient(HttpTools.java:1918)
        at com.xxxxxx.sdk.tools.HttpTools.access$100(HttpTools.java:154)
        at com.xxxxxx.sdk.tools.HttpTools$11.run(HttpTools.java:1651)
        at java.lang.Thread.run(Thread.java:929)
     Caused by: java.lang.ClassNotFoundException: Didn't find class "org.apache.commons.logging.LogFactory" on path: DexPathList[[zip file "/data/app/cn.xxxxxx.xxx.mi-nkXbCPUYbnY7-dXsVuKWBw==/base.apk"],nativeLibraryDirectories=[/data/app/cn.xxxxxx.xxx.mi-nkXbCPUYbnY7-dXsVuKWBw==/lib/arm, /data/app/cn.xxxxxx.xxx.mi-nkXbCPUYbnY7-dXsVuKWBw==/base.apk!/lib/armeabi, /system/lib, /hw_product/lib]]
        at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:196)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
        at org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager.<init>(ThreadSafeClientConnManager.java:155) 
        at com.xxxxxx.sdk.tools.HttpTools.getNewHttpClient(HttpTools.java:1918) 
        at com.xxxxxx.sdk.tools.HttpTools.access$100(HttpTools.java:154) 
        at com.xxxxxx.sdk.tools.HttpTools$11.run(HttpTools.java:1651) 
        at java.lang.Thread.run(Thread.java:929) 

我的代码：

private static HttpClient getNewHttpClient() {
    try {
        KeyStore trustStore = KeyStore.getInstance(KeyStore
                .getDefaultType());
        trustStore.load(null, null);

        SSLSocketFactory sf = new SSLSocketFactoryEx(trustStore);
        sf.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);

        HttpParams params = new BasicHttpParams();
        HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
        HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);
        SchemeRegistry registry = new SchemeRegistry();
        registry.register(new Scheme("http", PlainSocketFactory
                .getSocketFactory(), 80));
        registry.register(new Scheme("https", sf, 443));

        ClientConnectionManager ccm = new ThreadSafeClientConnManager(
                params, registry);

        return new DefaultHttpClient(ccm, params);
    } catch (Exception e) {
        return new DefaultHttpClient();
    }
}

看上去好像是没有 Lorg/apache/commons/logging/LogFactory 这个包， 于是我就把它下载下来给导进去

这里下载： http://commons.apache.org/proper/commons-logging/download_logging.cgi 

导进去又报了这样一个莫名其妙的错误

Dex file with version '39' cannot be used with min sdk level '29'

通篇没有找到 这个版本号在哪里设置的，这个问题找到一个方案。 我没有尝试  

因为我意识到可能是 由于导入的这个包引起的。

我把它重新删掉，不报这个错了！但是还是会引发上面的 crash。 所以我觉得是方向错了。

后面找到这个解决方案 解决了我的问题  androidmanifest.xml 文件中添加以下库的引用

<uses-library android:name ="org.apache.http.legacy" android:required ="false"/>

或者

build.gradle中添加下面的代码
android {
　　useLibrary 'org.apache.http.legacy'
}

那么问题来了，为什么会报这个问题呢？

org.apache.http.legacy.jar 是如何解决这个问题的？