第4个HttpClient 例子，下载指定图片并保存到请定目录

<dependencies>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.2</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.5</version>
</dependency>

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.commons.io.FileUtils;
import java.io.File;
import java.io.InputStream;

public class Demo02 {
public static void main(String[] args) throws Exception {
//创建HttpClient实例
CloseableHttpClient client = HttpClients.createDefault();
//创建httpget实例
HttpGet get = new HttpGet("https://www.oracle.com/us/assets/hp10p2-oracle-code-sprite-3861772.jpg");
//设置请求头信息
get.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:50.0) Gecko/20100101 Firefox/50.0");
//执行http get 请求
CloseableHttpResponse execute = client.execute(get);
//获取返回的实体
HttpEntity entity = execute.getEntity();
if (entity!=null){
//输入返回的内容
System.out.println("Content-Type:"+entity.getContentType().getValue());
InputStream inputStream=entity.getContent();
//保存到指定的目录
FileUtils.copyToFile(inputStream, new File("C://dljd4.jpg"));
}

//response 关闭
execute.close();
//httpclient 关闭
client.close();
}
}

Content-Type:image/jpeg; charset=

Process finished with exit code 0