Android http 请求

转载来自：Alex Zhou，本文链接：http://codingnow.cn/android/723.html

这篇文章主要实现了在Android中使用JDK的HttpURLConnection和Apache的HttpClient访问网络资源，服务端采用python+flask编写，使用Servlet太麻烦了。关于Http协议的相关知识，可以在网上查看相关资料。代码比较简单，就不详细解释了。

1. 使用JDK中HttpURLConnection访问网络资源

(1)get请求

public String executeHttpGet() {
        String result = null ;
        URL url = null ;
        HttpURLConnection connection = null ;
        InputStreamReader in = null ;
        try {
            url = new URL( "http://10.0.2.2:8888/data/get/?token=alexzhou" );
            connection = (HttpURLConnection) url.openConnection();
            in = new InputStreamReader(connection.getInputStream());
            BufferedReader bufferedReader = new BufferedReader(in);
            StringBuffer strBuffer = new StringBuffer();
            String line = null ;
            while ((line = bufferedReader.readLine()) != null ) {
                strBuffer.append(line);
            }
            result = strBuffer.toString();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (connection != null ) {
                connection.disconnect();
            }
            if (in != null ) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        }
        return result;
    }

注意：因为是通过android模拟器访问本地pc服务端，所以不能使用localhost和127.0.0.1，使用127.0.0.1会访问模拟器自身。Android系统为实现通信将PC的IP设置为10.0.2.2

(2)post请求

public String executeHttpPost() {
        String result = null ;
        URL url = null ;
        HttpURLConnection connection = null ;
        InputStreamReader in = null ;
        try {
            url = new URL( "http://10.0.2.2:8888/data/post/" );
            connection = (HttpURLConnection) url.openConnection();
            connection.setDoInput( true );
            connection.setDoOutput( true );
            connection.setRequestMethod( "POST" );
            connection.setRequestProperty( "Content-Type" , "application/x-www-form-urlencoded" );
            connection.setRequestProperty( "Charset" , "utf-8" );
            DataOutputStream dop = new DataOutputStream(
                    connection.getOutputStream());
            dop.writeBytes( "token=alexzhou" );
            dop.flush();
            dop.close();

            in = new InputStreamReader(connection.getInputStream());
            BufferedReader bufferedReader = new BufferedReader(in);
            StringBuffer strBuffer = new StringBuffer();
            String line = null ;
            while ((line = bufferedReader.readLine()) != null ) {
                strBuffer.append(line);
            }
            result = strBuffer.toString();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (connection != null ) {
                connection.disconnect();
            }
            if (in != null ) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        }
        return result;
    }

如果参数中有中文的话，可以使用下面的方式进行编码解码：

URLEncoder.encode( "测试" , "utf-8" )
URLDecoder.decode( "测试" , "utf-8" );

2.使用Apache的HttpClient访问网络资源
(1)get请求

public String executeGet() {
        String result = null ;
        BufferedReader reader = null ;
        try {
            HttpClient client = new DefaultHttpClient();
            HttpGet request = new HttpGet();
            request.setURI( new URI(
                    "http://10.0.2.2:8888/data/get/?token=alexzhou" ));
            HttpResponse response = client.execute(request);
            reader = new BufferedReader( new InputStreamReader(response
                    .getEntity().getContent()));

            StringBuffer strBuffer = new StringBuffer( "" );
            String line = null ;
            while ((line = reader.readLine()) != null ) {
                strBuffer.append(line);
            }
            result = strBuffer.toString();

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (reader != null ) {
                try {
                    reader.close();
                    reader = null ;
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        return result;
    }

（2）post请求

public String executePost() {
        String result = null ;
        BufferedReader reader = null ;
        try {
            HttpClient client = new DefaultHttpClient();
            HttpPost request = new HttpPost();
            request.setURI( new URI( "http://10.0.2.2:8888/data/post/" ));
            List<NameValuePair> postParameters = new ArrayList<NameValuePair>();
            postParameters.add( new BasicNameValuePair( "token" , "alexzhou" ));
            UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(
                    postParameters);
            request.setEntity(formEntity);

            HttpResponse response = client.execute(request);
            reader = new BufferedReader( new InputStreamReader(response
                    .getEntity().getContent()));

            StringBuffer strBuffer = new StringBuffer( "" );
            String line = null ;
            while ((line = reader.readLine()) != null ) {
                strBuffer.append(line);
            }
            result = strBuffer.toString();

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (reader != null ) {
                try {
                    reader.close();
                    reader = null ;
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        return result;
    }

3.服务端代码实现
上面是采用两种方式的get和post请求的代码，下面来实现服务端的代码编写，使用python+flask真的非常的简单，就一个文件，前提是你得搭建好python+flask的环境，代码如下：

#coding=utf-8

import json
from flask import Flask,request,render_template

app = Flask(__name__)

def send_ok_json(data = None ):
    if not data:
        data = {}
    ok_json = { 'ok' : True , 'reason' :' ',' data':data}
    return json.dumps(ok_json)

@app .route( '/data/get/' ,methods = [ 'GET' ])
def data_get():
    token = request.args.get( 'token' )
    ret = '%s**%s' % (token, 'get' )
    return send_ok_json(ret)

@app .route( '/data/post/' ,methods = [ 'POST' ])
def data_post():
    token = request.form.get( 'token' )
    ret = '%s**%s' % (token, 'post' )
    return send_ok_json(ret)

if __name__ = = "__main__" :
    app.run(host = "localhost" ,port = 8888 ,debug = True )

运行服务器，如图：

4. 编写单元测试代码
右击项目：new–》Source Folder取名tests，包名是：com.alexzhou.androidhttp.test（随便取，没有要求），结构如图：

在该包下创建测试类HttpTest，继承自AndroidTestCase。编写这四种方式的测试方法，代码如下:

public class HttpTest extends AndroidTestCase {

    @Override
    protected void setUp() throws Exception {
        Log.e( "HttpTest" , "setUp" );
    }

    @Override
    protected void tearDown() throws Exception {
        Log.e( "HttpTest" , "tearDown" );
    }

    public void testExecuteGet() {
        Log.e( "HttpTest" , "testExecuteGet" );
        HttpClientTest client = HttpClientTest.getInstance();
        String result = client.executeGet();
        Log.e( "HttpTest" , result);
    }

    public void testExecutePost() {
        Log.e( "HttpTest" , "testExecutePost" );
        HttpClientTest client = HttpClientTest.getInstance();
        String result = client.executePost();
        Log.e( "HttpTest" , result);
    }

    public void testExecuteHttpGet() {
        Log.e( "HttpTest" , "testExecuteHttpGet" );
        HttpClientTest client = HttpClientTest.getInstance();
        String result = client.executeHttpGet();
        Log.e( "HttpTest" , result);
    }

    public void testExecuteHttpPost() {
        Log.e( "HttpTest" , "testExecuteHttpPost" );
        HttpClientTest client = HttpClientTest.getInstance();
        String result = client.executeHttpPost();
        Log.e( "HttpTest" , result);
    }
}

附上HttpClientTest.java的其他代码：

public class HttpClientTest {

    private static final Object mSyncObject = new Object();
    private static HttpClientTest mInstance;

    private HttpClientTest() {

    }

    public static HttpClientTest getInstance() {
        synchronized (mSyncObject) {
            if (mInstance != null ) {
                return mInstance;
            }
            mInstance = new HttpClientTest();
        }
        return mInstance;
    }

  /**...上面的四个方法...*/
}

现在还需要修改Android项目的配置文件AndroidManifest.xml，添加网络访问权限和单元测试的配置，AndroidManifest.xml配置文件的全部代码如下：

< manifest xmlns:android = "http://schemas.android.com/apk/res/android"
    package = "com.alexzhou.androidhttp"
    android:versionCode = "1"
    android:versionName = "1.0" >

    < uses-permission android:name = "android.permission.INTERNET" />

    < uses-sdk
        android:minSdkVersion = "8"
        android:targetSdkVersion = "15" />

    < application
        android:icon = "@drawable/ic_launcher"
        android:label = "@string/app_name"
        android:theme = "@style/AppTheme" >
        < uses-library android:name = "android.test.runner" />

        < activity
            android:name = ".MainActivity"
            android:label = "@string/title_activity_main" >
            < intent-filter >
                < action android:name = "android.intent.action.MAIN" />

                < category android:name = "android.intent.category.LAUNCHER" />
            </ intent-filter >
        </ activity >
    </ application >

    < instrumentation
        android:name = "android.test.InstrumentationTestRunner"
        android:targetPackage = "com.alexzhou.androidhttp" />

</ manifest >

注意：
android:name=”android.test.InstrumentationTestRunner”这部分不用更改
android:targetPackage=”com.alexzhou.androidhttp”，填写应用程序的包名

5.测试结果
展开测试类HttpTest，依次选中这四个测试方法，右击：Run As–》Android Junit Test。
(1)运行testExecuteHttpGet，结果如图：
(2)运行testExecuteHttpPost，结果如图：
(3)运行testExecuteGet，结果如图：
(4)运行testExecutePost，结果如图：