1.网络配置
在res/xml
新建network_security_config

<network-security-config>
    <base-config cleartextTrafficPermitted="true"/>
</network-security-config>

在Manifeste

android:networkSecurityConfig="@xml/network_security_config"
 <uses-permission android:name="android.permission.INTERNET"/>

2.get请求
网络请求必须新开一个线程

 new Thread() {
                    @Override
                    public void run() {
                        super.run();
                        get();
                    }
                }.start();

private void get() {
        try {
            URL url = new URL("http://class.imooc.com/sc/60/learn");
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(6000);
            if (conn.getResponseCode() == HttpsURLConnection.HTTP_OK) {
                InputStream in = conn.getInputStream();
                int len = 0;
                byte[] b = new byte[1024];
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                while ((len = in.read()) > -1) {
                    baos.write(b, 0, len);
                }
                String str = new String(baos.toByteArray());
                Log.e("***********************", str);
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

3.POST请求

    private void post() {

        try {
            URL url = new URL("http://www.imooc.com/api/okhttp/postmethod");
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            conn.setConnectTimeout(6000);
            conn.setDoOutput(true);

            //根据网站自己设置
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            OutputStream os = conn.getOutputStream();
            os.write(("account=111&pwd=111").getBytes());
            if (conn.getResponseCode() == HttpsURLConnection.HTTP_OK) {
                int len = 0;
                byte[] b = new byte[1024];
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                InputStream in = conn.getInputStream();
                while ((len = in.read(b)) > -1) {
                    baos.write(b, 0, len);
                }
                String str = new String(baos.toByteArray());
                Log.e("**************", str);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }