Android多线程编程

Handler
AsyncTask

HTTPURLConnection使用

1. get方式使用

private void initData() {
    new Thread(() -> {
        try {
            //创建远程url连接对象
            URL url = new URL(smartUrl);
            //通过远程url对象打开一个连接，强制转换为HttpUrlConnection类型
            HttpURLConnection con = (HttpURLConnection) url.openConnection();
            //获取结果码
            int responseCode = con.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) {
                //通过连接对象获取一个输入流，向远程读取
                InputStream inputStream = con.getInputStream();
                //封装输入流is，并指定字符集
                InputStreamReader ist = new InputStreamReader(inputStream);
                char[] chars = new char[1024];
                int len = 0;
                StringBuffer sb = new StringBuffer();
                while ((len = ist.read(chars)) != -1) {
                    sb.append(chars, 0, len);
                }
                String json = sb.toString();
                Message message = Message.obtain();
                message.what = 1;
                message.obj = json;
                handler.sendMessage(message);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }).start();
}

Handler handler = new Handler() {
    @Override
    public void handleMessage(@NonNull Message msg) {
        super.handleMessage(msg);
        switch (msg.what) {
            case 1:
                String json = (String) msg.obj;
                SmartBean smartBean = new Gson().fromJson(json, SmartBean.class);
                List<SmartBean.ResultsBean> results = smartBean.getResults();
                ArrayList<SmartBean.ResultsBean> list = new ArrayList<>();
                list.addAll(results);
                SmartAdapter adapter = new SmartAdapter(MainActivity.this, list);
                lv_smart.setAdapter(adapter);
                break;
        }
    }
};

2. post方式使用

private void login() {
    new Thread(() -> {
        try {
            //登录url
            String loginUrl = "https://www.wanandroid.com/user/login";
            // 创建远程url连接对象
            URL url = new URL(loginUrl);
            //通过远程url对象打开一个连接，强制转换为HttpUrlConnection类型
            HttpURLConnection con = (HttpURLConnection) url.openConnection();
            //设置连接方式：POST
            con.setRequestMethod("POST");
            //设置超时
            con.setConnectTimeout(10000);
            con.setReadTimeout(10000);
            //设置是否向httpUrlConnection输出，设置是否从httpUrlConnection读入，此外发送post请求必须设置这两个
            //setDoOutput默认值为：false，当向远程服务器传送数据/写数据时，需要设置为true
            con.setDoOutput(true);
            //setDoInput默认值为：true，当前向远程服务读取数据时，设置为true，该参数可有可无
            con.setDoInput(true);
            //设置传入参数的格式:请求参数应该是 name1=value1&name2=value2 的形式
            con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

            //通过连接对象获取一个输出流
            OutputStream os = con.getOutputStream();
            //通过输出流对象将参数写出去/传输出去，它是通过字节数组写出的
            String param = "username=anfly&password=123456";
            os.write(param.getBytes());

            //获取结果码
            int responseCode = con.getResponseCode();
            if (responseCode == 200) {
                //通过连接对象获取一个输入流，向远程读取
                InputStream is = con.getInputStream();
                //封装输入流is，并指定字符集
                InputStreamReader isr = new InputStreamReader(is);
                char[] chars = new char[1024];
                StringBuffer sb = new StringBuffer();
                int len = 0;
                while ((len = isr.read(chars)) != -1) {
                    sb.append(chars, 0, len);
                }

                //sb转为string
                String json = sb.toString();
                Log.e("TAG", "json=" + json);

                //关流
                is.close();
                isr.close();
            }
            //关流
            os.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }).start();
}