Question

我有一个网址数组，我想存储我在数据库中读取的网址中的信息。我的问题是我的数据列表太大url如果读取序列化每个url从上面露水存储在数据库中需要时间。

我知道有一种方法可以使用线程进行操作，但我不知道该怎么做，请帮助我。或者无论你的方法是什么

try {
    String lstUrls = "http://www.java2s.com/Tutorials/Java/Scala/index.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0020__Scala_Variables.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0040__Scala_Variable_Declarations.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0060__Scala_Semicolons.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0080__Scala_Code_Blocks.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0090__Scala_Comments.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0100__Scala_Type_Hierarchy.htm\n";
    String[] urls = lstUrls.split("\n");
    for (String url : urls) {
        Document doc = Jsoup.connect(url).userAgent("Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.152 Safari/537.36").get();
        Elements select = doc.select("div.row");
        String html = select.html();
        System.out.println(html);
        /*
         insert html to database
         */
    }
} catch (IOException ex) {
    ex.printStackTrace();
}

Answer 1

我建议在插入数据库之前压缩数据。

//PreparedStatement.setBytes(1,compress(html));

public static byte[] compress(String str) throws Exception {
    if (str == null || str.length() == 0) {
        return null;
    }
    ByteArrayOutputStream obj = new ByteArrayOutputStream();
    GZIPOutputStream gzip = new GZIPOutputStream(obj);
    gzip.write(str.getBytes("UTF-8"));
    gzip.close();
    return obj.toByteArray();
} 

public static String decompress(byte[] bytes) throws Exception {
    GZIPInputStream gis = new GZIPInputStream(new ByteArrayInputStream(bytes));
    BufferedReader bf = new BufferedReader(new InputStreamReader(gis,"UTF-8"));
    String outStr = "";
    String line;
    while ((line = bf.readLine()) != null) {
        outStr += line;
    }
    return outStr;
}

第二种方法，将html数据保存到文件中，并仅存储数据库中的文件路径。

long ts = System.currentTimeMillis();
String filePath = String.valueOf(ts)+".gz"; 
saveToFile(filePath ,html);
--------    
public static void saveToFile(String filePath, String text) {
    try {
        GZIPOutputStream gzos = new GZIPOutputStream(new FileOutputStream(filePath));
        gzos.write(text.getBytes("UTF-8"));
        gzos.finish();
        gzos.close();

    } catch (IOException ex) {
        ex.printStackTrace();
    }
}

Answer 2

要使用多个线程来检索数据，您可以执行以下操作：

    Executor ex = Executors.newFixedThreadPool(3);
    String lstUrls = "http://www.java2s.com/Tutorials/Java/Scala/index.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0020__Scala_Variables.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0040__Scala_Variable_Declarations.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0060__Scala_Semicolons.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0080__Scala_Code_Blocks.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0090__Scala_Comments.htm\n"
            + "http://www.java2s.com/Tutorials/Java/Scala/0100__Scala_Type_Hierarchy.htm\n";
    String[] urls = lstUrls.split("\n");
    for (final String url : urls) {
        try {
            ex.execute(new Runnable() {
                @Override
                public void run() {
                    try {
                        Document doc = Jsoup
                                .connect(url)
                                .userAgent(
                                        "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.152 Safari/537.36")
                                .get();
                        Elements select = doc.select("div.row");
                        String html = select.html();
                        System.out.println(html);
                        /*
                         * insert html to database
                         */
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            });
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

这将使用3个线程同时处理网址，如果你想使用3个以上的线程更改此行Executor ex = Executors.newFixedThreadPool(3);并将3替换为你想要的任何数字。

您可以找到有关Executors here

的更多信息

Jsoup将内容保存到数据库中

2 个答案: