java后台調用接口並返回值

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
public class HttpOrderUtil {
	// 接口
	private static final String post_url = "接口的地址";

	public static String httpURLConnectionPOST(需要傳的參數) {
		StringBuilder sb = new StringBuilder();
		try {
			URL url = new URL(post_url);//把字符串轉換為URL請求地址
			HttpURLConnection connection = (HttpURLConnection) url
					.openConnection();//此時cnnection只是為一個連接對象,待連接中 
			connection.setConnectTimeout(5 * 1000);//設置連接超時時間為5秒  
			connection.setReadTimeout(20 * 1000);//設置讀取超時時間為20秒   
			connection.setDoOutput(true);//設置連接輸出流為true,默認false
			connection.setDoInput(true);//設置連接輸入流為true  
			connection.setRequestMethod("POST");//設置請求方式為post 
			connection.setUseCaches(false);// post請求緩存設為false  
			connection.setInstanceFollowRedirects(true);//設置該HttpURLConnection實例是否自動執行重定向 
			connection.setRequestProperty("Content-Type",
					"application/x-www-form-urlencoded;charset=utf-8");//請求的content-type為application/x-www-form-urlencoded;
																		//charset=UTF-8
			connection.connect();//建立連接
			DataOutputStream dataout = new DataOutputStream(
					connection.getOutputStream());//創建輸入輸出流,用於往連接里面輸出攜帶的參數
			String 參數= "參數="
					+ URLEncoder.encode(需要傳的參數, "utf-8");
			dataout.writeBytes(參數);
			dataout.flush();//輸出完成后刷新並關閉流  
			dataout.close();
			//System.out.println(connection.getResponseCode());
			// 如果請求響應碼是200，則表示成功 
			if (connection.getResponseCode() == 200) {
				BufferedReader bf = new BufferedReader(new InputStreamReader(
						connection.getInputStream(), "UTF-8"));
				String line;
				while ((line = bf.readLine()) != null) {
					sb.append(line);
				}
				bf.close();
			}
			connection.disconnect();//斷開連接
		} catch (IOException e) {
			e.printStackTrace();
		}
		return sb.toString();
	}

}