java8 实现网页下载，大致分为4步，分别是:给定目标网页链接->与目标主机建立连接->读入网页文件流->写入本地文件 。会用到java io 和 java net库。程序代码如下，留有注释。

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import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;

public class test {
    public static void main(String[] args) {
        try {
            new test().downloadPage();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private String downloadPage() throws IOException {
        // 目标网页链接
        String url = "https://hexo.io/zh-cn/";
        String inputLine = null;
        try {
            URL pageUrl = new URL(url);
            BufferedReader br = new BufferedReader(
                new InputStreamReader(pageUrl.openStream(), "utf-8"));
            //程序文件目录建目录 download，用于存放下载的网页
            File file = new File("D:\\Test\\maliang\\index.html"); 
            FileOutputStream out = new FileOutputStream(file);
            OutputStreamWriter write = new OutputStreamWriter(out, "utf-8");
            // 将输入流读入到变量中，再写入到文件
            while ((inputLine = br.readLine()) != null) {
                write.write(inputLine);
                System.out.println(inputLine);
            }
            br.close();
            write.close();
            System.err.println("下载完毕!");
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
        return url;
    }
}