Java URLConnection請求的參數進行封裝

package com.hospital.netengine;

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.net.URLEncoder;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.lang3.StringUtils;

/**
 * 網絡請求入口
 * 
 * @author scott
 *
 */
public class NetHttpClient {

	/**
	 * 向指定URL發送GET方法的請求
	 * 
	 * @param url
	 *            發送請求的URL
	 * @param param
	 *            請求參數
	 * @return 請求結果
	 */
	public static String sendGet(String url, Map<String, String> params) {
		StringBuilder result = new StringBuilder();
		BufferedReader in = null;
		try {
			String urlNameString = url + "?" + getUrlParamsFromMap(params);
			URL realUrl = new URL(urlNameString);
			// 打開和URL之間的連接
			URLConnection connection = realUrl.openConnection();
			// 設置通用的請求屬性
			connection.setRequestProperty("accept", "*/*");
			connection.setRequestProperty("connection", "Keep-Alive");
			connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
			// 建立實際的連接
			connection.connect();
			// 獲取所有響應頭字段
			Map<String, List<String>> map = connection.getHeaderFields();
			System.out.println("響應頭信息:");
			// 遍歷所有的響應頭字段
			for (String key : map.keySet()) {
				System.out.println(key + "--->" + map.get(key));
			}
			// 定義 BufferedReader輸入流來讀取URL的響應
			in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
			String line;
			while ((line = in.readLine()) != null) {
				result.append(line);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally {// 使用finally塊來關閉輸入流
			try {
				if (in != null) {
					in.close();
				}
			} catch (Exception e2) {
				e2.printStackTrace();
			}
		}
		return result.toString();
	}

	/**
	 * 發送POST方法的請求
	 * 
	 * @param url
	 *            發送請求的 URL
	 * @param param
	 *            請求參數。
	 * @return 響應結果
	 */
	public static String sendPost(String url, Map<String, String> params) {
		PrintWriter out = null;
		BufferedReader in = null;
		StringBuilder result = new StringBuilder();
		try {
			URL realUrl = new URL(url);
			// 打開和URL之間的連接
			URLConnection conn = realUrl.openConnection();
			// 設置通用的請求屬性
			conn.setRequestProperty("accept", "*/*");
			conn.setRequestProperty("connection", "Keep-Alive");
			conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
			// 發送POST請求必須設置如下兩行
			conn.setDoOutput(true);
			conn.setDoInput(true);
			// 獲取URLConnection對象對應的輸出流
			out = new PrintWriter(conn.getOutputStream());
			// 發送請求參數
			out.print(getUrlParamsFromMap(params));
			// flush輸出流的緩衝
			out.flush();
			// 定義BufferedReader輸入流來讀取URL的響應
			in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
			String line;
			while ((line = in.readLine()) != null) {
				result.append(line);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally {// 使用finally塊來關閉輸出流、輸入流
			try {
				if (out != null) {
					out.close();
				}
				if (in != null) {
					in.close();
				}
			} catch (IOException ex) {
				ex.printStackTrace();
			}
		}
		return result.toString();
	}

	/**
	 * description:將map轉換成url參數格式: name1=value1&name2=value2
	 * 
	 * @param map
	 * @return
	 */
	public static String getUrlParamsFromMap(Map<String, String> map) {
		try {
			if (null != map) {
				StringBuilder stringBuilder = new StringBuilder();
				for (Map.Entry<String, String> entry : map.entrySet()) {
					stringBuilder.append(URLEncoder.encode(entry.getKey(), "UTF-8")).append("=")
							.append(URLEncoder.encode(entry.getValue(), "UTF-8")).append("&");
				}
				String content = stringBuilder.toString();
				if (content.endsWith("&")) {
					content = StringUtils.substringBeforeLast(content, "&");
				}
				return content;
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}
}