android客户端访问网络工具类

package com.yqq.loginclient.utils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

/**
 * 连接服务器
 *
 * @author yqq_coder
 *
 */
public class LoginUtils {

	public LoginUtils() {
		// TODO Auto-generated constructor stub
	}
	/**
	 * http://10.1.17.208:8080/LoginService/LoginServlet?userName=Lihua&passWord=123456
	 * http://localhost:8080/?userName=Lihua&passWord=123456
	 * @param ip 服务器IP
	 * @param userName GET方式传递参数用户名
	 * @param passWord 密码
	 * @return
	 */
	public static String connect(String ip, String userName, String passWord) {
		String str = "http://" + ip
				+ ":8080/LoginService/LoginServlet?userName="+userName+"&passWord="+passWord;
		URL url=null;
		InputStream inputStream = null;
		HttpURLConnection connection = null;
		StringBuffer sb = null;// 线程安全
		try {
			url = new URL(str);//获得URL对象
			try {
				connection = (HttpURLConnection) url.openConnection();
				connection.setConnectTimeout(3000);
				connection.setRequestMethod("GET");//GET方式提交参数
				connection.setDoOutput(true);//设置可以向服务器读写
				connection.setDoInput(true);
				//请求成功
				if (connection.getResponseCode() == 200) {
					inputStream = connection.getInputStream();
					Reader reader = new InputStreamReader(inputStream, "UTF-8");
					//打包成字符流
					BufferedReader bufferedReader = new BufferedReader(reader);
					String str1 = null;
					sb = new StringBuffer();
					while ((str1 = bufferedReader.readLine()) != null) {
						sb.append(str1);
					}

				}

			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		} catch (MalformedURLException e) {

			e.printStackTrace();
			//关闭流很重要
		} finally {
			if (inputStream != null) {
				try {
					inputStream.close();
					inputStream = null;
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}

			}
			if (connection != null) {
				connection.disconnect();
				connection = null;
			}

		}
		if (sb != null) {
			return new String(sb);
		}

		return "服务器异常！";

	}

}