在Java中使用HttpClient调用HTTPS接口，具体方法如下：

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.message.BasicHeader;
import org.apache.http.util.EntityUtils;
public class HttpClientUtil {
@SuppressWarnings("resource")
public static String doPost(String url,String jsonstr,String charset){
HttpClient httpClient = null;
HttpPost httpPost = null;
String result = null;
try{
httpClient = new SSLClient();
httpPost = new HttpPost(url);
httpPost.addHeader("Content-Type", "application/json");
StringEntity se = new StringEntity(jsonstr);
se.setContentType("text/json");
se.setContentEncoding(new BasicHeader("Content-Type", "application/json"));
httpPost.setEntity(se);
HttpResponse response = httpClient.execute(httpPost);
if(response != null){
HttpEntity resEntity = response.getEntity();
if(resEntity != null){
result = EntityUtils.toString(resEntity,charset);
}
}
}catch(Exception ex){
ex.printStackTrace();
}
return result;
}
}