爬取页面的json数据

package pachong;

import java.io.BufferedReader;

import java.io.FileOutputStream;

import java.io.FileWriter;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStreamWriter;

import java.net.MalformedURLException;

import java.net.URL;

import java.net.URLConnection;

public class Spider {public static void main(String[] args) {

String filepath = "d:/125.html";

String url_str = "http://aqicn.org/forecast/beijing/cn/";

URL url = null;

try {

url = new URL(url_str);

} catch (MalformedURLException e) {

e.printStackTrace();

}

String charset = "utf-8";

int sec_cont = 1000;

try {

URLConnection url_con = url.openConnection();

url_con.setDoOutput(true);

url_con.setReadTimeout(10 * sec_cont);

url_con.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)");

InputStream htm_in = url_con.getInputStream();

String htm_str = InputStream2String(htm_in,charset);

saveHtml(filepath,htm_str);

} catch (IOException e) {

e.printStackTrace();

}

}

/**

* Method: saveHtml

* Description: save String to file

* @param filepath

* file path which need to be saved

* @param str

* string saved

*/

public static void saveHtml(String filepath, String str){

try {

/*@SuppressWarnings("resource")

FileWriter fw = new FileWriter(filepath);

fw.write(str);

fw.flush();*/

OutputStreamWriter outs = new OutputStreamWriter(new FileOutputStream(filepath, true), "utf-8");

outs.write(str);

System.out.print(str);

outs.close();

} catch (IOException e) {

System.out.println("Error at save html...");

e.printStackTrace();

}

}

/**

* Method: InputStream2String

* Description: make InputStream to String

* @param in_st

* inputstream which need to be converted

* @param charset

* encoder of value

* @throws IOException

* if an error occurred

*/

public static String InputStream2String(InputStream in_st,String charset) throws IOException{

BufferedReader buff = new BufferedReader(new InputStreamReader(in_st, charset));

StringBuffer res = new StringBuffer();

String line = "";

while((line = buff.readLine()) != null){

res.append(line);

}

return res.toString();

}

}