JAVA super simple crawler example (1), java crawler example

JAVA super simple crawler example (1), java crawler example

Crawls the data of the entire page and effectively extracts information. comments are not nonsense:

Public class Reptile {public static void main (String [] args) {String url1 = ""; // input the page address you want to crawl. InputStream is = null; // create an input stream for reading the stream BufferedReader br = null; // wrap the stream to speed up reading StringBuffer html = new StringBuffer (); // Save the data for reading the page. string temp = ""; // create a temporary String to save each row of data read, and then html calls the append method to write data to temp; try {URL url2 = new URL (url1 ); // obtain the URL; is = url2.openStream (); // open the stream and prepare to start reading data; br = new BufferedReader (new InputStream Reader (is); // package the stream into a response stream and call br. readLine () can improve reading efficiency, reading a row each time; while (temp = br. readLine ())! = Null) {// read data, call br. the readLine () method reads a row of data each time and assigns the value to temp. If no data exists, the value = null, which jumps out of the loop. html. append (temp); // append the temp value to html. Note that the difference between String and StringBuffere is that the former is not variable and the latter is variable.} // System. out. println (html); // print out all the code for crawling the page; if (is! = Null) // The next step is to close the stream to prevent resource waste. {is. close (); is = null;} Document doc = Jsoup. parse (html. toString (); // parse the page through Jsoup to generate a document object; Elements elements = doc. getElementsByClass ("XX"); // get it by class Name (XX). An array object named Elements contains the data we want, as for the div value, open the browser and press F12. for (Element element: elements) {System. out. println (element. text (); // print the information of each node; you can choose to retain the data you want, generally obtaining a fixed index;} catch (MalformedURLException e) {// TODO Auto-generated catch block e. printStackTrace ();} catch (IOException e) {// TODO Auto-generated catch block e. printStackTrace ();}}

Upload a self-crawled image and use fusioncharts to generate a report. (If int type data is captured, the report can be generated intuitively)