Android手机app与服务器端进行通信（一）

正文

当前手机app与服务器端通信，通常有两种方式，一种是长连接利用Socket进行连接，另一种是短连接通过Http进行连接。相较而言，短连接不损耗系统资源，只有当客户端app进行操作时才会与服务器端进行连接，而长连接客户端与服务器端是一直保持连接的，适用于服务器端主动向客户端推送信息服务，一些即时通讯。

HTTP通信协议

最近做了一个移动输液系统，用到了HTTP通信协议。以前做项目时没有用到过，自己摸索查找资料学习的。现在，我把自己对Http的理解拿出来和大家交流一下，有不对的地方，欢迎大家提出。HTTP协议通信有两种方法，一种是HttpGet,，另一种是HttpPost

HttpGet客户端

    //通过HttpClient父类DefaultHttpClient获取client对象
    HttpClient client=new DefaultHttpClient();
    //url:服务器端和客户端当前是连在一个局域网中，180.104.151.72是服务器端的IP地址，8080是tomacat接口，MobileInfusionServer是在tomacat中运行的一个项目名称，LoginServlet是一个Servlet，loginName和loginPassword是Android端app传入服务器中的字符串。
    url="http://180.104.151.72:8080/MobileInfusionServer/LoginServlet?LoginName="+loginName+"&loginPassword="+loginPassword;
    //获取HttpGet方法的对象
    HttpGet get=new HttpGet(url);
    //响应
    HttpResponse response = client.execute(get);
    //statusCode是与服务器端Servlet请求返回的验证码
    int statusCode = response.getStatusLine().getStatusCode();
    //如果statusCode==200，说明请求成功，在Android里是HttpStatus中的SC_OK，否则返回异常
    if(statusCode!=HttpStatus.SC_OK){
    throw new ServiceRulesException(
        "服务器端异常";
     }
    //接收服务器返回值，编码方式是UTF-8
    String result=EntityUtils.toString(response.getEntity(), "UTF-8");
    //假设服务器端返回值是success字符串
    if(result.equals("success")){

    }else{
     throw new ServiceRulesException(
        "服务器端异常";
    }

HttpGet请求的服务器端LoginServlet

public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    //设置接收返回值的字符编码方式为UTF-8
    request.setCharacterEncoding("UTF-8");
    response.setCharacterEncoding("UTF-8");
    //接收客户端传入的字符串loginName，LoginPassword
    String loginName=request.getParameter("LoginName");
    String loginPassword=request.getParameter("LoginPassword");、
    //在控制台打印传入的值
    System.out.println(loginName);
    System.out.println(loginPassword);
    /**
     * text/html
     */
    response.setContentType("text/html;charset-UTF-8");
    /**
     *  通过response.getWriter()获取out对象返回给客户端值
     */
    PrintWriter out=null;
    try {
        out=response.getWriter();
        /**
         * 登陆的业务判断
         */
        if(loginName.equals("zcl")&&loginPassword.equals("123")){
            //登陆成功
            out.print("success");
        }else {
            out.print("failed");
        }
    } finally{
        if(out!=null){
            out.close();
        }
    }
}

HttpPost : Android客户端

public class UserServiceImpl implements UserService {
    private static final String TAG = "UserServiceImpl";

    @Override
    public void userLogin(String loginName, String loginPassword)
            throws Exception {
        // TODO Auto-generated method stub
        Log.d(TAG, loginName);
        Log.d(TAG, loginPassword);

        /**
         * NameValuePair----->List----->HttpEntity---->HttpPost--
         * -->HttpClient
         */
        HttpParams params = new BasicHttpParams();
        // 通过params设置请求字符集
        HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);
        // 设置客户端和服务器连接的超时时间
        HttpConnectionParams.setConnectionTimeout(params, 3000);
        // 设置服务器响应的超时时间------》SocketTimeOutException
        HttpConnectionParams.setSoTimeout(params, 3000);
        // 配置协议和端口
        SchemeRegistry schreg = new SchemeRegistry();
        schreg.register(new Scheme("http", PlainSocketFactory
                .getSocketFactory(), 80));
        schreg.register(new Scheme("https", PlainSocketFactory
                .getSocketFactory(), 433));
        ClientConnectionManager conman = new ThreadSafeClientConnManager(
                params, schreg);

        //通过HttpClient解析url地址
        HttpClient client = new DefaultHttpClient(conman, params);
        String url="http://180.104.151.72:8080/MobileInfusionServer/LoginServlet";
        HttpPost post = new HttpPost(url);

        //将要传入服务器端的字符串放入NameValuePair
        NameValuePair paramloginName = new BasicNameValuePair("LoginName",
                loginName);
        BasicNameValuePair paramloginPassword = new BasicNameValuePair(
                "LoginPassword", loginPassword);
        //传入的是两个字符串，可以放入List集合中
        List parameters = new ArrayList();
        parameters.add(paramloginName);
        parameters.add(paramloginPassword);
        post.setEntity(new UrlEncodedFormEntity(parameters, HTTP.UTF_8));
        HttpResponse response = client.execute(post);

        int statusCode = response.getStatusLine().getStatusCode();
        if (statusCode != HttpStatus.SC_OK) {
            throw new ServiceRulesException("服务器端异常");
        }

        String result = EntityUtils.toString(response.getEntity(), HTTP.UTF_8);

        if (result.equals("success")) {

        } else {

        }
}

HttpPost请求的服务器端LoginServlet

和HttpGet方法一样，基于安全的角度看，建议使用Post方法

将Http连接封装成一个工具类

在一个项目中，我们通常会有很多个方法需要与服务器端进行Http连接，每个方法，我们都需要这样一步步进行连接，这样就会显得代码冗余，为了节省程序猿的工作量，我们需要将他们封装成一个工具类，每次连接时，我们只需要调用这个工具类就可以了。

package com.xzit.mobileinfusion.util;
import java.util.List;

import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.ClientConnectionManager;
import org.apache.http.conn.scheme.PlainSocketFactory;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;

import android.util.Log;

import com.xzit.mobileinfusion.activity.LoginActivity;
import com.xzit.mobileinfusion.service.ServiceRulesException;


public class HttpConnectUtil {

    private HttpParams params;

    private ClientConnectionManager conman;

    private HttpClient client;

    private HttpPost post;

    private HttpResponse response;


    public HttpConnectUtil() {
        super();
        /**
         * NameValuePair----->List----->HttpEntity---->HttpPost--
         * -->HttpClient
         */
        params = new BasicHttpParams();
        // 通过params设置请求字符集
        HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);
        // 设置客户端和服务器连接的超时时间
        HttpConnectionParams.setConnectionTimeout(params, 3000);
        // 设置服务器响应的超时时间------》SocketTimeOutException
        HttpConnectionParams.setSoTimeout(params, 3000);
        // 配置协议和端口
        SchemeRegistry schreg = new SchemeRegistry();
        schreg.register(new Scheme("http", PlainSocketFactory
                .getSocketFactory(), 80));
        schreg.register(new Scheme("https", PlainSocketFactory
                .getSocketFactory(), 433));
        conman = new ThreadSafeClientConnManager(
                params, schreg);
        client = new DefaultHttpClient(conman, params);
    }

    /**
     * 连接Client,传入对象到服务上
     * @param uri
     * @return
     */
    public String postMessage(String uri,List parameters) throws Exception{
        post = new HttpPost(uri);
        post.setEntity(new UrlEncodedFormEntity(parameters, HTTP.UTF_8));
        response = client.execute(post);

        int statusCode = response.getStatusLine().getStatusCode();
        if (statusCode != HttpStatus.SC_OK) {
            throw new ServiceRulesException("服务器端错误");
        }

        String result = EntityUtils.toString(response.getEntity(), HTTP.UTF_8);
        return result;
    }


    /**
     * 连接Client，不传入对象到服务器上，直接从服务器端获取返回值
     * @param uri
     * @return
     */
    public String postMessage(String uri) throws Exception{
        post = new HttpPost(uri);
        response = client.execute(post);

        int statusCode = response.getStatusLine().getStatusCode();
        if (statusCode != HttpStatus.SC_OK) {
            throw new ServiceRulesException("服务器端错误");
        }
        Log.e("aa", "66666666");
        String result = EntityUtils.toString(response.getEntity(), HTTP.UTF_8);
        Log.e("aa", result);
        return result;
    }


}

调用HttpConnectUtil工具类进行连接

package com.xzit.mobileinfusion.serviceImpl;

import java.util.ArrayList;
import java.util.List;

import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;

import android.util.Log;

import com.xzit.mobileinfusion.service.PatientService;
import com.xzit.mobileinfusion.util.HttpConnectUtil;

public class PatientServiceImpl implements PatientService{
    private static final String TAG = "PatientServiceImpl";

    /**
     * 注册账号
     */
    @Override
    public String patientRegiter(String s_p_name, String s_sex, String s_id_card) throws Exception {
        Log.d(TAG,s_p_name);
        Log.d(TAG,s_id_card);

        String uri = "http://192.168.1.100:8080/MobileInfusionServer/AddPatientAction";

        /**
         * JSON数据的封装
         * **********************************************
         */
        JSONObject object = new JSONObject();
        object.put("p_name", s_p_name);
        object.put("sex", s_sex);
        object.put("id_card", s_id_card);

        NameValuePair parameter = new BasicNameValuePair("Patient",
                object.toString());
        List params = new ArrayList();
        params.add(parameter);

        /**
         *调用HttpConnectUtil工具类进行Http连接
         */
        String result = new HttpConnectUtil().postMessage(uri, params);

        return result;
    }