URLConnection sends post and get requests

1. Request class example

package com.until;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;

/**
 * Public class for sending http requests
 * @author Administrator
 */
public class HttpRequest {
	/**
	 * Send a GET method request to the specified URL
	 * @param url the URL to send the request to
	 * @param param Request parameter, the request parameter should be in the form of name1=value1&name2=value2.
	 * The response result of the remote resource represented by the @return URL
	 */
	public static String sendGet(String url, String param) {
		String result = "";
		BufferedReader in = null;
		try {
			String urlNameString = url + "?" + param;
			URL realUrl = new URL(urlNameString);
			//Open the connection to the URL
			URLConnection connection = realUrl.openConnection();
			//Set common request attributes
			connection.setRequestProperty("accept", "*/*");
			connection.setRequestProperty("connection", "Keep-Alive");
			connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
			//establish the actual connection
			connection.connect();
			// get all response header fields
			Map<String, List<String>> map = connection.getHeaderFields();
			// loop through all response header fields
			for (String key : map.keySet()) {
				System.out.println(key + "--->" + map.get(key));
			}
			//Define the BufferedReader input stream to read the response of the URL
			in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
			String line;
			while ((line = in.readLine()) != null) {
				result += line;
			}
		} catch (Exception e) {
			System.out.println("An exception occurred when sending a GET request!" + e);
			e.printStackTrace ();
		}
		// use finally block to close the input stream
		finally {
			try {
				if (in != null) {
					in.close();
				}
			} catch (Exception e2) {
				e2.printStackTrace();
			}
		}
		return result;
	}

	/**
	 * Send a POST request to the specified URL
	 * @param url the URL to send the request to
	 * @param param Request parameter, the request parameter should be in the form of name1=value1&name2=value2.
	 * The response result of the remote resource represented by @return
	 */
	public static String sendPost(String url, String param) {
		PrintWriter out = null;
		BufferedReader in = null;
		String result = "";
		try {
			URL realUrl = new URL (url);
			//Open the connection to the URL
			URLConnection conn = realUrl.openConnection();
			//Set common request attributes
			conn.setRequestProperty("accept", "*/*");
			conn.setRequestProperty("connection", "Keep-Alive");
			conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
			//To send a POST request, the following two lines must be set
			conn.setDoOutput(true);
			conn.setDoInput(true);
			// Get the output stream corresponding to the URLConnection object
			out = new PrintWriter(conn.getOutputStream());
			//Send request parameters
			out.print(param);
			//flush the buffer of the output stream
			out.flush();
			//Define the BufferedReader input stream to read the response of the URL, (processing garbled characters)
			in = new BufferedReader(new InputStreamReader(conn.getInputStream(),"utf-8"));
			
			String line;
			while ((line = in.readLine()) != null) {
				result += line;
			}
		} catch (Exception e) {
			System.out.println("Error sending POST request!" + e);
			e.printStackTrace ();
		}
		// Use finally block to close output stream, input stream
		finally {
			try {
				if (out != null) {out.close();}
				if (in != null) {in.close();}
			} catch (IOException ex) {
				ex.printStackTrace();
			}
		}
		return result;
	}	
}

 

2. Test class example

package com.test;

import com.until.HttpRequest;

public class HttpUtilTest {
	public static void main(String[] args) {
		 //Send GET request
//        String s=HttpRequest.sendGet("http://localhost:6144/Home/RequestString", "key=123&v=456");
//        System.out.println(s);
        
        // send POST request
        String sr = HttpRequest.sendPost("http://php.weather.sina.com.cn/xml.php", "city=武汉&password=DJOYnieT8234jlsK&day=0");
        System.out.println(sr);
	}
}