HttpClient发送GET和POST请求所需的org.apache.http包

HttpClient发送GET和POST请求，传参需要用到StringEntity,NameValuePair,这两个类需要导入httpcore.jar。可以直接maven下载：
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpcore</artifactId>
    <version>4.4.9</version>
</dependency>