import java.io.ByteArrayOutputStream;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URL;

 import javax.net.ssl.HttpsURLConnection;

 public class FirstTest {

     public static void main(String[] args) throws Exception {

         // TODO 自动生成的方法存根

         long start=System.currentTimeMillis();

         System.out.println("开始");

         for(int i=1;i<=100;i++) {

 //            double r=(0+Math.random()*10000);

 //            System.out.println(r);

             String url="https://source.unsplash.com/random";//一个随机图片接口

 //            +(0+Math.random()*10000);可以在random后面加入一个随机数避免图片重复

             getImg(url,i);

             System.out.println("完成"+i);

         }

         long end=System.currentTimeMillis();

         System.out.println("运行时间:"+(end-start)/1000+"秒");

     }

     private static void getImg(String u,int i){

         URL url;

         try {

             url = new URL(u);

             HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();

             conn.setRequestMethod("GET");

             conn.setConnectTimeout(5*1000);

             InputStream in = conn.getInputStream();

             byte[] data = readInputStream(in);

             File f = new File("C:\\Users\\Administrator\\Desktop\\img\\"+i+".jpg");

             FileOutputStream out = new FileOutputStream(f);

             out.write(data);

             out.close();

         } catch (IOException e) {

             // TODO 自动生成的 catch 块

             e.printStackTrace();

         }

     }

     private static byte[] readInputStream(InputStream ins) throws IOException {

         // TODO 自动生成的方法存根

         ByteArrayOutputStream out = new ByteArrayOutputStream();

         byte[] buffer = new byte[1024];

         int len = 0;

         while ((len = ins.read(buffer)) != -1) {

             out.write(buffer, 0, len);

         }

         ins.close();

         return out.toByteArray();

     }

 }