Android 原生代码实现网络请求

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本文导读

使用URL访问网络资源：下载图片
使用URLConnection进行网络请求：GET&POST
使用HttpURLConnection进行网络请求：GET&POST
原生代码实现及解析：注释
Demo代码下载

使用URL访问网络资源

URL对象代表统一资源定位器，指向互联网资源的指针，由协议名，主机，端口和资源组成。
URI代表统一资源标识符，不能用于定位资源，唯一的作用就是解析。
URL则包含一个可打开该资源书入输入流，因此可以说URL是URI的特例。

URL实现图片下载

private Bitmap bitmap;Handler handler = new Handler() { @Override public void handleMessage(Message msg) {   if (msg.what == 0x123) {               //使用ImageView显示图片               ivUrl.setImageBitmap(bitmap);            }         }      };      new Thread() {       @Override       public void run() {         try {           URL url = new URL("http://192.168.199.100:8080/image/D.png");//URl对象，指向本地服务器的一张图片           InputStream is = url.openStream();//打开输入流           bitmap = BitmapFactory.decodeStream(is);//解析成bitmap对象           handler.sendEmptyMessage(0x123);//handler机制UI显示图片           OutputStream os = openFileOutput("demon.png", MODE_PRIVATE);//打开一个文件对应的输入流           byte[] bytes = new byte[1024];           int has;           while ((has = is.read(bytes)) > 0) {             os.write(bytes, 0, has);//将URL对应的图片下载到本地          }          is.close();//关闭流          os.close();//关闭流       } catch (Exception e) {        e.printStackTrace();     }  }}.start();

使用URLConnection进行网络请求

URL的openConnection返回一个URLConnection对象，表示与该URL建议通信连接。通过该对象，可以发送请求，读取资源。
创建URL连接，发生请求，读取资源步骤如下：

使用openConnection创建一个URLConnection对象
设置URLConnection的参数和普通请求属性
GET请求，使用connect方法建立连接即可；POST请求，则需要获取URLConnection实例的输出流发送请求参数
访问资源的输入流读取数据

PS:必须先使用输出流发送请求参数，再使用输入流获取数据

实现URLConnection的GET,POST请求工具类

public class GetPostUrl {    public static GetPostUrl getPost = new GetPostUrl();//单例    public static GetPostUrl getGetPost() {        return getPost;    }    /**     * 发送get请求     *     * @param url     * @return     */    public static String get(final String url) {        final StringBuilder sb = new StringBuilder();        FutureTask<String> task = new FutureTask<String>(new Callable<String>() {            @Override            public String call() throws Exception {                BufferedReader br = null;                InputStreamReader isr = null;                URLConnection conn;                try {                    URL geturl = new URL(url);                    conn = geturl.openConnection();//创建连接                    conn.connect();//get连接                    InputStreamReader isr = new InputStreamReader(conn.getInputStream());//输入流                    br = new BufferedReader(isr);                    String line = null;                    while ((line = br.readLine()) != null) {                        sb.append(line);//获取输入流数据                    }                    System.out.println(sb.toString());                } catch (Exception e) {                    e.printStackTrace();                } finally {//执行流的关闭                    if (br != null) {                        try {                        if (br != null) {                            br.close();                        }                        if (isr != null) {                            isr.close();                        }                    } catch (IOException e) {                        e.printStackTrace();                    } }}                return sb.toString();            }        });        new Thread(task).start();        String s = null;        try {            s = task.get();//异步获取返回值        } catch (Exception e) {            e.printStackTrace();        }        return s;    } /**     * POST请求     *     * @param url url     * @param map 请求参数的map集合形式     * @return     */    public static String post(final String url, final Map<String, String> map) {        final StringBuilder sb = new StringBuilder();        FutureTask<String> task = new FutureTask<String>(new Callable<String>() {            @Override            public String call() throws Exception {                DataOutputStream out = null;                BufferedReader br = null;                URLConnection conn;                URL posturl = new URL(url);                try {                    conn = posturl.openConnection();//创建连接                    conn.setDoInput(true);//post请求必须设置                    conn.setDoOutput(true);//post请求必须设置                    out = new DataOutputStream(conn                            .getOutputStream());//输出流                    StringBuilder request = new StringBuilder();                    for (String key : map.keySet()) {                        request.append(key + "=" + URLEncoder.encode(map.get(key), "UTF-8") + "&");                    }//连接请求参数                    out.writeBytes(request.toString());//输出流写入请求参数                    out.flush();                    out.close();                    br = new BufferedReader(new InputStreamReader(conn.getInputStream()));//获取输入流                    String line;                    while ((line = br.readLine()) != null) {                        sb.append(line);                    }                    System.out.println(sb.toString());                } catch (Exception e) {                    e.printStackTrace();                } finally {//执行流的关闭                    if (br != null) {                        br.close();                    }                    if (out != null) {                        out.close();                    } }                return sb.toString(); }        });        String s = null;        new Thread(task).start();        try {            s = task.get();//异步获取返回值        } catch (Exception e) {            e.printStackTrace();        }        return s;    }}

使用HttpURLConnection进行网络请求

HttpURLConnection是URLConnection的子类，在URLConnection的基础上进一步改进增加了操作HTTP资源的便捷方法。
创建URL连接，发生请求，读取资源步骤与URLConnection基本一致。

区别

使用setRequestMethod()方法设置请求方式”GET”或者”POST”
使用getResponseCode()获取响应码，判断请求是否成功
可以使用disconnect()断开请求连接

HttpURLConnection实现GET与POST工具类

public class HttpConnectionUtil {    public static HttpConnectionUtil http = new HttpConnectionUtil();    public static HttpConnectionUtil getHttp() {        return http;    }    public String getRequset(final String url) {        final StringBuilder sb = new StringBuilder();        FutureTask<String> task = new FutureTask<String>(new Callable<String>() {            @Override            public String call() throws Exception {                HttpURLConnection connection = null;                BufferedReader reader = null;                try {                    URL requestUrl = new URL(url);                    connection = (HttpURLConnection) requestUrl.openConnection();                    connection.setRequestMethod("GET");                    connection.setConnectTimeout(8000);                    connection.setReadTimeout(8000);                    if (connection.getResponseCode() == 200) {                        InputStream in = connection.getInputStream();                        reader = new BufferedReader(new InputStreamReader(in));                        String line;                        while ((line = reader.readLine()) != null) {                            sb.append(line);                        }                        System.out.println(sb);                    }                } catch (Exception e) {                    e.printStackTrace();                } finally {                    if (reader != null) {                        reader.close();                    }                    if (connection != null) {                        connection.disconnect();//断开连接，释放资源                    }                }                return sb.toString();            }        });        new Thread(task).start();        String s = null;        try {            s = task.get();        } catch (Exception e) {            e.printStackTrace();        }        return s;    }    public String postRequset(final String url, final Map<String, String> map) {        final StringBuilder sb = new StringBuilder();        FutureTask<String> task = new FutureTask<String>(new Callable<String>() {            @Override            public String call() throws Exception {                HttpURLConnection connection = null;                BufferedReader reader = null;                try {                    URL requestUrl = new URL(url);                    connection = (HttpURLConnection) requestUrl.openConnection();                    connection.setRequestMethod("POST");                    connection.setConnectTimeout(8000);//链接超时                    connection.setReadTimeout(8000);//读取超时                    //发送post请求必须设置                    connection.setDoOutput(true);                    connection.setDoInput(true);                    connection.setUseCaches(false);                    connection.setInstanceFollowRedirects(true);                    connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");                    DataOutputStream out = new DataOutputStream(connection                            .getOutputStream());                    StringBuilder request = new StringBuilder();                    for (String key : map.keySet()) {                        request.append(key + "=" + URLEncoder.encode(map.get(key), "UTF-8") + "&");                    }                                  out.writeBytes(request.toString());//写入请求参数                    out.flush();                    out.close();                    if (connection.getResponseCode() == 200) {                        InputStream in = connection.getInputStream();                        reader = new BufferedReader(new InputStreamReader(in));                        String line;                        while ((line = reader.readLine()) != null) {                            sb.append(line);                        }                        System.out.println(sb);                    }                } catch (Exception e) {                    e.printStackTrace();                } finally {                    if (reader != null) {                        reader.close();//关闭流                    }                    if (connection != null) {                        connection.disconnect();//断开连接，释放资源                    }                }                return sb.toString();            }        });        new Thread(task).start();        String s = null;        try {            s = task.get();        } catch (Exception e) {            e.printStackTrace();        }        return s;    }}

运行测试

具体测试代码请下载查看，直接上效果图。

Demo Module项目下载

CSDN

http://download.csdn.net/detail/demonliuhui/9836919

GitHub

https://github.com/DeMonLiu623/StudyDemo/tree/master/AndroidNet

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