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前言说明：当前我的工程中使用的httpclient-4.3.6.jar和httpcore-4.3.3.jar版本的包。

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpcore</artifactId>
    <version>4.3.3</version>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.3.6</version>
</dependency>   

今天执行阿里云的OSS相关操作时，首先提示以下异常:

java.lang.ClassNotFoundException: org.apache.http.ssl.TrustStrategy

详细如下：

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/ssl/TrustStrategy
    at com.aliyun.oss.OSSClient.<init>(OSSClient.java:246)
    at com.aliyun.oss.OSSClient.<init>(OSSClient.java:206)
    at com.autonavi.oss.client.DefaultOSSClient.<clinit>(DefaultOSSClient.java:12)
    at com.autonavi.oss.put.Upload.put(Upload.java:20)
    at com.autonavi.oss.put.Upload.main(Upload.java:58)
Caused by: java.lang.ClassNotFoundException: org.apache.http.ssl.TrustStrategy
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    ... 5 more

从上面报错提示可以看出，是org/apache/http/ssl/TrustStrategy下面找不到TrustStrategy这个类，我查了下依赖中的httpclient-4.3.6.jar和httpcore-4.3.3.jar两个包，均没有这个类。

而4.4版本中有ssl路径：

及对应org/apache/http/ssl/TrustStrategy方法。

很明显是版本不对，应该换成新版本。

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpcore</artifactId>
    <version>4.4</version>
</dependency> 

重新执行代码，上面异常已经消失，不过出现新异常：

java.lang.NoClassDefFoundError: org/apache/http/conn/ssl/NoopHostnameVerifier

异常详细：

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/conn/ssl/NoopHostnameVerifier
    at com.aliyun.oss.common.comm.DefaultServiceClient.createHttpClientConnectionManager(DefaultServiceClient.java:230)
    at com.aliyun.oss.common.comm.DefaultServiceClient.<init>(DefaultServiceClient.java:78)
    at com.aliyun.oss.OSSClient.<init>(OSSClient.java:246)
    at com.aliyun.oss.OSSClient.<init>(OSSClient.java:206)
    at com.autonavi.oss.client.DefaultOSSClient.<clinit>(DefaultOSSClient.java:12)
    at com.autonavi.oss.put.Upload.put(Upload.java:20)
    at com.autonavi.oss.put.Upload.main(Upload.java:58)
Caused by: java.lang.ClassNotFoundException: org.apache.http.conn.ssl.NoopHostnameVerifier
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    ... 7 more

很明显是版本不对，是由于httpclient-4.3.6.jar缺少NoopHostnameVerifier方法：

而4.4版本中有这个方法：

应该换成新版本，即换成httpclient-4.4.jar

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.4</version>
</dependency>   

查看下jar包中相应路径存在上面那个类。

最后再次执行，执行成功，无异常！

所以，下次碰到以下两个异常时：
1、

java.lang.ClassNotFoundException: org.apache.http.ssl.TrustStrategy

2、

java.lang.NoClassDefFoundError: org/apache/http/conn/ssl/NoopHostnameVerifier

需要升级httpclient.jar和httpcore.jar两个包的版本，4.3的版本中不含有上述两个类，需要同时升级到4.4版本。

即替换为httpclient-4.4.jar和httpcore-4.4.jar