android通過HttpClient與伺服器JSON互動

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通過昨天對HttpClient的學習，今天封裝了HttpClient類

代碼如下：

package com.tp.soft.util;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.util.ArrayList;import java.util.List;import java.util.Map;import org.apache.http.HttpResponse;import org.apache.http.HttpStatus;import org.apache.http.NameValuePair;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.HttpPost;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.message.BasicNameValuePair;import org.apache.http.protocol.HTTP;public class HttpUtil {    public static String postRequest(String serverPath, Map<String, String> params, String encoding){        List<NameValuePair> paramPair = new ArrayList<NameValuePair>();        if(params != null && !params.isEmpty()){            for(Map.Entry<String, String> entry : params.entrySet()){                paramPair.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));            }        }        try {            HttpClient client = new DefaultHttpClient();            HttpPost post = new HttpPost(serverPath);            post.setEntity(new UrlEncodedFormEntity(paramPair, HTTP.UTF_8));            HttpResponse response = client.execute(post);            if(response.getStatusLine().getStatusCode() == HttpStatus.SC_OK){                BufferedReader br = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));                //資料                String reqData = null;                String responseData = "";                while((reqData = br.readLine()) != null){                    responseData += reqData;                }                br.close();                return responseData;            }        } catch (ClientProtocolException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }        return "postRequest error";    }}

然後通過調用HttpUtil類來達成與伺服器互動

package com.tp.soft.app;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import android.app.Activity;import android.os.Bundle;import android.view.LayoutInflater;import android.view.Menu;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ListView;import android.widget.TextView;import com.google.gson.Gson;import com.google.gson.reflect.TypeToken;import com.tp.soft.entity.User;import com.tp.soft.util.HttpUtil;public class MainActivity extends Activity {        private ListView mListView;    private TextView mContentTxt;    private TextView mTimeTxt;        private String serverPath = "http://122.226.178.54:8080/uploadApp/LoginServlet";    private static final String ENCODING = "utf-8";    private List<User> userList;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        loadList();         mListView = (ListView) findViewById(R.id.list_id);        mListView.setAdapter(new BaseAdapter() {                        @Override            public View getView(int position, View convertView, ViewGroup parent) {                if(null == convertView){                    convertView = LayoutInflater.from(getApplicationContext()).inflate(R.layout.item, null);                }                                TextView textView = (TextView) convertView.findViewById(R.id.contentTxt);                textView.setText(userList.get(position).getUsername());                return convertView;            }                        @Override            public long getItemId(int position) {                return position;            }                        @Override            public Object getItem(int position) {                return position;            }                        @Override            public int getCount() {                return userList.size();            }        });    }    private List<User> loadList() {        Map<String, String> params = new HashMap<String, String>();        String data = HttpUtil.postRequest(serverPath, params, ENCODING);        userList = new Gson().fromJson(data, new TypeToken<List<User>>() {}.getType());            return userList;    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        getMenuInflater().inflate(R.menu.main, menu);        return true;    }}

伺服器端則採用了servlet

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        response.setCharacterEncoding("utf-8");        String uname = request.getParameter("uname");        String pwd = request.getParameter("pwd");                PrintWriter pw = response.getWriter();        Gson gson = new GsonBuilder().create();        List<User> userList = new ArrayList<User>();        User user = new User();        user.setUsername("zs");        user.setPassword("1");        userList.add(user);                User user1 = new User();        user1.setUsername("lisi");        user1.setPassword("2");        userList.add(user1);        String json = gson.toJson(userList);        pw.print(json);    }