https://www.meitulu.com/ java下载图片

package downloadpic;

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.select.Elements;

import javax.print.Doc;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;

public class donloadBeauty extends constantString {
    public static int target = 18;
    public static void main(String argv[]) throws IOException {
        Document document = Jsoup.connect(new constantString().url_root).get();
        //System.out.println(document.text());
        Elements number_beauty_elements = document.getElementsByClass("p_title");
        int number_beauty = number_beauty_elements.size();
        System.out.println(number_beauty);

        //to get all the name and url
        String[] beauty = new String[number_beauty];
        String[] beauty_title = new String[number_beauty];
        for (int i = 0; i < number_beauty; i++) {
            beauty[i] = number_beauty_elements.get(i)
                    .select("a[href]").attr("href").toString();
            beauty_title[i] = number_beauty_elements.get(i)
                    .text();
            System.out.println(i + ":	file name:" + beauty_title[i] + "
" + "url is: " + beauty[i]);
        }

        //test just one url
        //to get user name
        String user_home = "/home/" + System.getProperty("user.name") + "/Beauty/";
        //to creat folder
        String file_full_path = user_home + beauty_title[target].replaceAll("/", "");
        File file = new File(file_full_path);
        if (file.exists()) {
            System.out.println("file already exits");
        } else {
            file.mkdirs();
        }

        //get first element content
        Document document1_beauty = Jsoup.connect(beauty[target]).get();
        String pic_number_string = null;
        //pic_number.startsWith("图片数量：");
        //int pic_number = Integer.parseInt(pic_number_string);
        Elements elements_p = document1_beauty.getElementsByClass("c_l").select("p");
        int size_p = elements_p.size();
        int position = 0;
        for(int n = 0; n < size_p; n ++){
            pic_number_string = elements_p.get(n).text().toString();
            if(pic_number_string.endsWith("张")){
                position = n;
                break;
            }
        }
        pic_number_string = document1_beauty.getElementsByClass("c_l")
                .select("p").get(position).text().toString();
        System.out.println(pic_number_string);

        //to get the number
        int index_last_0 = pic_number_string.lastIndexOf(" ");
        String temp_string = pic_number_string.substring(0, index_last_0);
        System.out.println(temp_string);
        int index_last_1 = temp_string.lastIndexOf(" ");
        //System.out.println(pic_number_string.substring(index_last_1));

        String number_string = pic_number_string.substring(index_last_1, index_last_0)
                .replaceAll(" ", "");
        System.out.println(number_string);
        int pic_number = Integer.parseInt(number_string);
        System.out.println("the pic number is: " + pic_number);

        //get specific url
        Document document_1 = Jsoup.connect(beauty[target]).get();
        Elements elements = new Elements();
        int i = document_1.getElementsByClass("content").select("img").size();

        System.out.println("" + i);
        for (int j = 0; j < i; j++) {
            String href = document_1.getElementsByClass("content").select("img")
                    .get(j).attr("src").toString();
            System.out.println(j + "," + "the url is:" + href);
        }
        String url_people = document_1.getElementsByClass("content").select("img")
                .get(0).attr("src").toString();
        System.out.println(url_people);

        //to get all the pic file url
        int pic_index_last_0 = url_people.lastIndexOf("/");
        String temp_string_temp = url_people.substring(0, pic_index_last_0);//to get https://mtl.gzhuibei.com/images/img/20779
        String userful_string = url_people.substring(pic_index_last_0);//to get 1.jpg
        int to_get_dot = userful_string.lastIndexOf(".");
        String extension_string = userful_string.substring(to_get_dot);//to get .jpg
        System.out.println(extension_string);
        System.out.println(userful_string);
        System.out.println(temp_string_temp);
        String[] beauty_full_url = new String[pic_number];
        for (int k = 0; k < pic_number; k++) {
            beauty_full_url[k] = temp_string_temp + "/" + (k+1) + extension_string;
            System.out.println(k +"	" + beauty_full_url[k]);
        }

        //to download the file
        int bytesum = 0;
        int byteread = 0;
        System.out.println(file_full_path +  "	url is:	" + target + ":	"+ beauty[target]);
        //System.out.println(target + beauty[target]);
        for(int l = 0; l < pic_number; l ++){
            URL url = new URL(beauty_full_url[l]);
            String file_name = l + 1 + extension_string;
            String file_full_name = file_full_path + "/" + file_name;
            File file_new = new File(file_full_name);
            if(file_new.exists()){
                System.out.println("file already exists!");
            }else{
                try{
                    URLConnection conn = url.openConnection();
                    InputStream inStream = conn.getInputStream();
                    FileOutputStream fs = new FileOutputStream(file_full_name);

                    byte[] buffer = new byte[2048];
                    int length;
                    while ((byteread = inStream.read(buffer)) != -1) {
                        bytesum += byteread;
                        //System.out.println(bytesum / 1024);
                        fs.write(buffer, 0, byteread);
                    }
                    System.out.println("**********" + file_name + "**********");

                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }
}