Android客户端使用HttpClient发起web数据访问
HttpClient与服务器数据交互方式：HttpPost和HttpGet 分别对应Post和Get提交。因为要做Android客户端的缘故，所以就必须实现客户端与服务器实现数据交互，以保证数据链条的通畅，实现数据闭环。由于之前对Android客户端访问web数据没有设置权限，所以可以很好的访问系统资源，但是如果是开发应用这种方式就存在极大的安全隐患，一个Host或Get提交过去数据就获取到了，web端系统完全就是裸奔。所以web端权限管理很有必要，也就不用过于担心Android客户端带来的安全隐患。Android新手学习一般都会遇到问题，前两天就遇到web端设置了权限而Android客户端发起访问获取不到数据的问题。
获取JSON遇到权限问题：http://my.oschina.net/boonya/blog/317057 这篇文章和本文要讲的内容有点关系。
1.HttpPost与HttpGet实现用户登录和列表展现
编写一个测试Activity，MainActivity.
package com.boonya.httpclienttest;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.json.JSONArray;
import org.json.JSONObject;
import com.boonya.httpclienttest.utils.HtttpClientUtil;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
public class MainActivity extends Activity
{
private static final String TAG = "MainActivity";
private List> videos = null;
private HashMap video = null;
private ListView listView = null;
private static String loginurl = "http://192.168.1.147:8090/wtms/androidservice/login";
private static String getdataurl = "http://192.168.1.147:8090/wtms/androidservice/videos.avd";
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
listView = (ListView) findViewById(R.id.videos);
postMethod();
getMethod();
}
/**
* HttpGet获取服务器数据显示
*
* @param url
*/
protected void getMethod()
{
HttpGet request = new HttpGet(getdataurl);
//request.setHeader("Cookie", HtttpClientUtil.getCookie());//设置cookie
try
{
//设置请求参数项
//request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
HttpClient client = HtttpClientUtil.getInstance();
//执行请求返回相应
HttpResponse response = client.execute(request);
// 判断请求是否成功
if (response.getStatusLine().getStatusCode() == 200)
{ // 200表示请求成功
StringBuilder builder = new StringBuilder();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String s = null;
while ((s = bufferedReader.readLine()) != null)
{
builder.append(s);
}
// String out = EntityUtils.toString(entity, "UTF-8");
String msg = builder.toString();
Log.d("log", ">>>>执行 方法 getMethod()获取到范围值："+msg);
JSONArray jsonArray = new JSONArray(msg);
videos = new ArrayList>();
for (int i = 0; i < jsonArray.length(); i++)
{
JSONObject jsonObject = (JSONObject) jsonArray.get(i);
int id = jsonObject.getInt("id");
String name = jsonObject.getString("name");
int timelength = jsonObject.getInt("time");
video = new HashMap();
video.put("id", id);
video.put("name", name);
video.put("timelength", "时长为:" + timelength);
videos.add(video);
}
SimpleAdapter adapter = new SimpleAdapter(this, videos, R.layout.item, new String[]
{ "name", "timelength" }, new int[]
{ R.id.title, R.id.timelength });
listView.setAdapter(adapter);
}
} catch (Exception e)
{
e.printStackTrace();
Log.e(TAG, e.toString());
Toast.makeText(MainActivity.this, "获取数据失败", Toast.LENGTH_LONG).show();
}
}
/**
* HttpPost提交数据
*/
@SuppressWarnings(
{ "unchecked", "rawtypes" })
protected void postMethod()
{
try
{
// 使用ApacheHttp客户端进行连接(重要方法)
HttpClient client = HtttpClientUtil.getInstance();
// 如果是Get提交则创建HttpGet对象，否则创建HttpPost对象
// POST提交的方式
HttpPost request = new HttpPost(loginurl);
// 如果是Post提交可以将参数封装到集合中传递
List params = new ArrayList();
params.add(new BasicNameValuePair("username", "test"));
params.add(new BasicNameValuePair("password", "test"));
// UrlEncodedFormEntity用于将集合转换为Entity对象
request.setEntity(new UrlEncodedFormEntity(params,HTTP.UTF_8));
try
{
// 获取相应消息
HttpResponse response = client.execute(request);
StringBuilder builder = new StringBuilder();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
// 操作cookie
/* List cookies = ((AbstractHttpClient) client).getCookieStore().getCookies();
if(cookies!=null&&cookies.size()>0)
{
for (int i = 0; i < cookies.size(); i++)
{
HtttpClientUtil.setCookie(cookies.get(i).getValue());
}
}*/
String s =null;
while((s = bufferedReader.readLine())!=null){
builder.append(s);
}
String string=builder.toString();
Log.d("log", ">>>>执行 方法 postMethod()获取到范围值："+string);
} catch (ClientProtocolException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
}
} catch (UnsupportedEncodingException e)
{
e.printStackTrace();
}
}
}
2.实现客户端与服务器cookie共享
这里采用单例模式实现HttpClient对象在Android客户端的唯一性，用户在登录系统后，这个对象会记录用户的Cookie，一旦建立客户端与服务器的访问认证，以后就可以任意发送HTTP请求到服务器请求或操作资源了。
package com.boonya.httpclienttest.utils;
import org.apache.http.client.HttpClient;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
public class HtttpClientUtil
{
/** 设置请求超时10秒钟 */
private static final int REQUEST_TIMEOUT = 10 * 1000;
/** 设置等待数据超时时间10秒钟 */
private static final int SO_TIMEOUT = 10 * 1000;
private static HttpClient instance;
/** 记住cookie字符串*/
private static String cookie;
/**
* 自定义方法：初始化HttpClient，并设置超时
*
* @return 返回：HttpClient 对象
*/
private HtttpClientUtil()
{
}
public static String getCookie()
{
return cookie;
}
public static void setCookie(String cookie)
{
HtttpClientUtil.cookie = cookie;
}
public static HttpClient getInstance()
{
if (instance == null)
{
BasicHttpParams httpParams = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParams, REQUEST_TIMEOUT);
HttpConnectionParams.setSoTimeout(httpParams, SO_TIMEOUT);
instance = new DefaultHttpClient(httpParams);
}
return instance;
}
}
优化HttpClientUtil的cookie获取方法：
package com.boonya.httpclienttest.utils;
import java.util.List;
import org.apache.http.client.HttpClient;
import org.apache.http.cookie.Cookie;
import org.apache.http.impl.client.AbstractHttpClient;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
public class HtttpClientUtil
{
/** 设置请求超时10秒钟 */
private static final int REQUEST_TIMEOUT = 10 * 1000;
/** 设置等待数据超时时间10秒钟 */
private static final int SO_TIMEOUT = 10 * 1000;
private static HttpClient instance;
/** 记住cookie字符串 */
private static String cookie = null;
/**
* 自定义方法：初始化HttpClient，并设置超时
*
* @return 返回：HttpClient 对象
*/
private HtttpClientUtil()
{
}
public static String getCookie()
{
// 确保实例存在
HtttpClientUtil.getInstance();
// 获取cookie
List cookies = ((AbstractHttpClient) instance).getCookieStore().getCookies();
if (cookies != null && cookies.size() > 0)
{
for (int i = 0; i < cookies.size(); i++)
{
cookie = cookies.get(i).getValue();
}
}
return cookie;
}
public static HttpClient getInstance()
{
if (instance == null)
{
BasicHttpParams httpParams = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParams, REQUEST_TIMEOUT);
HttpConnectionParams.setSoTimeout(httpParams, SO_TIMEOUT);
instance = new DefaultHttpClient(httpParams);
}
return instance;
}
}