本帖最后由 renwuqiangg 于 2018-4-25 23:07 编辑
我发现这个网站的壁纸还不错 ，这些壁纸都是必应首页的背景，每天只更新一张！https://bing.ioliu.cn/ranking
如果一张一张下载太慢了，遂写了一个批量下载工具，原理也比较简单，适合初学者。输入页码，不一会儿就下载完了。只要明白了其中的原理，下载别的网站的壁纸改改相关代码就行了。
下载完后可以设置win10的背景为幻灯片，并定位到该文件夹。
只有3个类，DownloadThread.java，Msg.java，Test.java。一个jar包 ：Jsoup-1.8.2.jar。
[Java] 纯文本查看 复制代码 package com.ren;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
public class DownloadThread extends Thread {
private String filePath = "";
private String imgUrl = "";
private Msg msg;
public DownloadThread(String filePath, String imgUrl,Msg msg) {
this.filePath = filePath;
this.imgUrl = imgUrl;
this.msg = msg;
}
@Override
public void run() {
msg.addCount();
downImages(filePath, imgUrl);
}
/**
* 下载图片到指定目录
*
* @param filePath 文件路径
* @param imgUrl 图片URL
*/
public void downImages(String filePath, String imgUrl) {
// 若指定文件夹没有，则先创建
File dir = new File(filePath);
if (!dir.exists()) {
dir.mkdirs();
}
// 截取图片文件名
String fileName = imgUrl.substring(imgUrl.lastIndexOf('/') + 1, imgUrl.length());
String fileName0 = lexicalAnalysis(fileName)+".jpg";
// 写出的路径
File file = new File(filePath + File.separator + fileName0);
if(file.exists()){
System.out.println("文件已存在["+fileName+"]");
msg.addRepeat();
return ;
}
try {
URL url = new URL(imgUrl);
URLConnection connection = url.openConnection();
// 设置10秒的相应时间
connection.setConnectTimeout(10 * 1000);
InputStream in = connection.getInputStream();
BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(file));
byte[] buf = new byte[4096];
int size;
// 写入到文件
while (-1 != (size = in.read(buf))) {
out.write(buf, 0, size);
}
out.close();
in.close();
} catch (MalformedURLException e) {
msg.addError();
e.printStackTrace();
} catch (IOException e) {
msg.addError();
e.printStackTrace();
}
msg.addSuccess();
}
//原文件名似乎含有特殊字符导致程序出错，简易的词法分析过滤一下
public static String lexicalAnalysis(String str){
StringBuffer sb = new StringBuffer();
int status = 0;
for (int i = 0; i < str.length(); i++) {
char c = str.charAt(i);
if((c>='a'&&c<='z')||(c>='A'&&c<='Z')||(c>='0'&&c<='9')){
if(status==0){
status=1;
sb.append(c);
}else if(status==1){
sb.append(c);
}
}else{
if(status==1){
break;
}
}
}
return sb.toString();
}
}
Msg.java主要用于记录总共下载了多少，成功了多少等
[Java] 纯文本查看 复制代码 package com.ren;
public class Msg {
private int count;
private int repeat;
private int success;
private int error;
public synchronized void addCount(){
count++;
}
public synchronized void addRepeat(){
repeat++;
}
public synchronized void addSuccess(){
success++;
}
public synchronized void addError(){
error++;
}
@Override
public String toString() {
// TODO Auto-generated method stub
return "总共["+count+"]，成功["+success+"]，重复["+repeat+"]，异常["+error+"]";
}
}
这里采用线程池，开启10个线程进行下载，但好像网速还是只有100kb/s，可能是服务器的原因吧。
[Java] 纯文本查看 复制代码 package com.ren;
import java.io.IOException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
public class Test {
public static void main(String[] args) {
long start = System.currentTimeMillis();
try {
new Test().downloadBing(0,10);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
long end = System.currentTimeMillis();
System.out.println("耗时："+((end-start)/1000)+"s");
}
/**
* 必应下载榜
* @param formpage
* @param topage
* @throws IOException
* @throws ExecutionException
* @throws InterruptedException
*/
public void downloadBing(int formpage,int topage) throws IOException, InterruptedException, ExecutionException{
String downloadUrlPre = "https://bing.ioliu.cn";
String hostUrlPre = "https://bing.ioliu.cn/ranking?p=";
String filePath = "D:/renwu/Pictures/壁纸";
Msg msg = new Msg();
ExecutorService pool =Executors.newFixedThreadPool(10);
for (int i = formpage; i < topage; i++) {
System.out.println("正在下载第["+i+"]页，url:"+hostUrlPre+i);
Document doc = Jsoup.connect(hostUrlPre+i).get();
Elements divs = doc.select("a.ctrl.download");
for (Element element : divs) {
String href = element.attr("href");
String downloadUrl = downloadUrlPre+href;
pool.submit(new DownloadThread(filePath, downloadUrl,msg));
}
}
pool.shutdown();
while(true){
if(pool.isTerminated()){
System.out.println(msg);
break;
}
Thread.sleep(1000);
}
}
}
如何运行：在eclipse新建项目，百度下载Jsoup-1.8.2.jar，加入项目的build path。新建DownloadThread.java，Msg.java，Test.java三个类并将代码复制进去，运行test即可。 | 
发表于 2018-4-25 16:15
有成品吗？
