Android网络开发中GET与POST请求详解
小徐加油 人气:01.URI与URL
URI(Uniform Resource Identifier,统一资源标志符),表示web上的每一种可用资源,具体的东西例如HTML文档,图像、视频、程序等。
URL(Uniform Resource Locator,统一资源定 位 器),也就是网络地址。
URL是URI的一种。
URI是对网络资源更宽泛的一种标识。
URL通常指的是网络连接,更多以http://www开头。
2.申请一个天气的免费API
网址:https://www.yiketianqi.com/index/doc,登陆后会自动生成属于自己的appid和appsecret
3.GET请求
主要目的:从服务端获取符合条件的数据。
会向服务端发送少量数据,携带的参数会拼接在URL后面,参数是少量而有限的
GET请求的URL举例:
https://www.tianqiapi.com/free/day?cityid=10010&cityname=北京&data=20220728
协议(https://)域名及端口(www.tianqiapi.com:80) 路径(/free/day)条件(cityid=10010&cityname=北京&data=20220728)
NetUtil程序如下:
public class NetUtil{ public static String BASE_URL="https://v0.yiketianqi.com/free/day"; public static String APP_ID="14846972"; public static String APP_SECRET="Guya4Gz2"; public static String doGet(String url){ BufferedReader reader = null; String bookHSONString = null; try{ //1.HttpURLConnection建立连接 HttpURLConnection httpURLConnection = null; URL requestUrl = new URL(url); httpURLConnection = (HttpURLConnection)requestUrl.openconnection();//打开连接 httpURLConnection.setRequestMethod("GET");//两种方法GET/POST httpURLConnection.setConnectionTimeout(5000);//设置超时连接时间 httpURLConnection.connect(); //2.InputStream获取二进制流 InputStream inputstream = httpURLConnection.getInputStream(); //3.InputStreamReader将二进制流进行包装成BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream)); //4.从BufferedReader中读取String字符串,用StringBulider接收 StringBulider bulider = new StringBulider(); String line; while((line=reader.readLine())!=null){ bulider.append(line); bulider.append("\n"); } if(bulider.length()==0) { return null; } //5.StringBulider将字符串进行拼接 bookJSONString = bulider.toString(); }catch(MalformedURLException e){ e.printStackTrace(); }finally { // 关闭连接 if (urlConnection != null) { urlConnection.disconnect(); } if (reader != null) { try { reader.close(); } catch (IOException e) { e.printStackTrace(); } } } return bookJSONString; } public static String getWeatherOfCity(String city){ //拼接处get请求的url String weatherUrl = BASE_URL+"?"+"appid="+APP_ID+"&"+"appsecret="+APP_SECRET+"&"+"city="+city; //打印上面的url Log.d("fan","-----weatherUrl----"+weatherUrl); //调用上文所写的doGet方法,传参 String weatherResult = doGet(weatherUrl); return decodeUnicode(weatherResult); } //解码Unicode,将其转化为我们认识的汉字 public static String decodeUnicode(String unicodeStr) { if (unicodeStr == null) { return null; } StringBuffer retBuf = new StringBuffer(); int maxLoop = unicodeStr.length(); for (int i = 0; i < maxLoop; i++) { if (unicodeStr.charAt(i) == '\\') { if ((i < maxLoop - 5) && ((unicodeStr.charAt(i + 1) == 'u') || (unicodeStr.charAt(i + 1) == 'U'))) try { retBuf.append((char) Integer.parseInt(unicodeStr.substring(i + 2, i + 6), 16)); i += 5; } catch (NumberFormatException localNumberFormatException) { retBuf.append(unicodeStr.charAt(i)); } else retBuf.append(unicodeStr.charAt(i)); } else { retBuf.append(unicodeStr.charAt(i)); } } return retBuf.toString(); } }
MainActivity.java程序如下:
public class MainActivity extends AppCompatActivity{ private TextView tvContent; //此处写一个handler程序 private Handler mHandler = new Handler(Looper.myLooper()){ @Override public void handleMessage(@NonNull Message msg){ super.handlerMessage(msg); if(msg.what==0){ String strData = (String)msg.obj; tvContent.setText(strData); Toast.makeText(MainActivity.this,"主线程收到网络消息啦!",Toast.LENGTH_SHORT).show(); } } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); tvContent = findViewById(R.id.tv_content); } public void start(View view){ //做一个耗时任务 new Thread(new Runnable(){ @Override public void run(){ String stringFormNet = getStringFormNet(); //使用handler来发送消息 Message message = new Message(); message.what = 0;//用于区分是谁发的消息 message.obj = stringFormNet; mHandler.sendMessage(meaasge); } }).start(); Toast.makeText(MainActivity.this,"开启子线程请求网络!",Toast.LENGTH_SHORT).show(); } private String getStringFormNet(){ //从网络上获取字符串 return NetUtil.getWeatherofCity("深圳"); } }
运行结果:
4.POST请求
主要目的:向服务端提交数据。
也会接收少量服务端的响应数据,携带的参数会单独放到map中,参数是大量的。
POST请求的URL举例:
https://www.tianqiapi.com/free/day+Map<String,String><city_id,1010><city_name,北京><date,20220728>
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