常州阿里云代理商：android 4.0 网络请求

常州阿里云代理商提供的关于Android 4.0的网络请求的解释：

在Android 4.0中，可以使用HttpURLConnection或Apache HttpClient的实现来进行网络请求。而目前推荐使用HttpURLConnection，因为它更加简洁、高效，并且支持较新的协议（如HTTP/2）。

以下是HttpURLConnection进行网络请求的示例代码:

URL url = new URL("http://www.example.com");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");

// 可添加请求头信息
// connection.setRequestProperty("header", "value");

int responseCode = connection.getResponseCode();
BufferedReader reader = new BufferedReader(new InputStreamReader(
        connection.getInputStream()));
String inputLine;
StringBuilder response = new StringBuilder();

while ((inputLine = reader.readLine()) != null) {
    response.append(inputLine);
}
reader.close();

// 得到响应内容后的处理

对于POST请求，需要设置请求方法为POST，并且设置请求体内容：

URL url = new URL("http://www.example.com");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);

// 添加请求体内容并设置Content-Type
OutputStream outputStream = connection.getOutputStream();
outputStream.write("request body".getBytes("UTF-8"));
outputStream.flush();
outputStream.close();

int responseCode = connection.getResponseCode();
BufferedReader reader = new BufferedReader(new InputStreamReader(
        connection.getInputStream()));
String inputLine;
StringBuilder response = new StringBuilder();

while ((inputLine = reader.readLine()) != null) {
    response.append(inputLine);
}
reader.close();

// 得到响应内容后的处理

需要注意的是，在Android 4.0中，网络请求不能在主线程中进行，需要在子线程中运行。最简单的实现方式是使用AsyncTask。

在Android 4.0上发送网络请求可以使用以下方法：

1.使用HttpURLConnection

HttpURLConnection是Android自带的网络连接类，可以用于发送HTTP请求和接收响应。

URL url = new URL("http://www.example.com/api/sample");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");

InputStream inputStream = connection.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
StringBuffer response = new StringBuffer();
String line;
while ((line = reader.readLine()) != null) {
    response.append(line);
}
reader.close();
connection.disconnect();
String result = response.toString();

2.使用HttpClient

HttpClient是一个第三方库，可以在Android 4.0上使用。

HttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet("http://www.example.com/api/sample");

HttpResponse response = httpClient.execute(httpGet);
HttpEntity entity = response.getEntity();
InputStream inputStream = entity.getContent();

BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
StringBuffer result = new StringBuffer();
String line;
while ((line = reader.readLine()) != null) {
    result.append(line);
}
reader.close();
entity.consumeContent();
String resultString = result.toString();

注意：Android 6.0及以上版本已经移除了HttpClient库，应该使用HttpURLConnection代替。