This article does not explain, it is a tool class HttpUtils, which can be used directly!
/**
* Send a GET request
*
* @param url
* Destination address
* @param parameters
* Request parameters, Map type.
* @return remote response result
*/
public static String sendGet(String url, Map<String, String> parameters) {
String result = "";
BufferedReader in = null;// Read the response input stream
StringBuffer sb = new StringBuffer();// store parameters
String params = "";// parameters after encoding
try {
// encode request parameters
if (parameters.size() == 1) {
for (String name : parameters.keySet()) {
sb.append(name).append("=").append(java.net.URLEncoder.encode(parameters.get(name), "UTF-8"));
}
params = sb.toString();
} else {
for (String name : parameters.keySet()) {
sb.append(name).append("=").append(java.net.URLEncoder.encode(parameters.get(name), "UTF-8")).append("&");
}
String temp_params = sb.toString();
params = temp_params.substring(0, temp_params.length() - 1);
}
String full_url = url + "?" + params;
System.out.println(full_url);
// create URL object
java.net.URL connURL = new java.net.URL(full_url);
// Open the URL connection (a tcp connection to the server is established, no http request is actually sent!)
URLConnection urlConnection=connURL.openConnection();
java.net.HttpURLConnection httpConn = (java.net.HttpURLConnection) urlConnection;
// Set the generic request attribute (if an attribute with this keyword already exists, overwrite its value with the new value.)
httpConn.setRequestProperty("Accept", "*/*");
httpConn.setRequestProperty("Connection", "Keep-Alive");
httpConn.setRequestProperty("User-Agent","Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)");
// Establish the actual connection (the remote object becomes available. The header fields and contents of the remote object become accessible)
httpConn.connect();
// get response header
Map<String, List<String>> headers = httpConn.getHeaderFields();
// loop through all response header fields
for (String key : headers.keySet()) {
System.out.println(key + "\t：\t" + headers.get(key));
}
// Define the BufferedReader input stream to read the response of the URL and set the encoding method
in = new BufferedReader(new InputStreamReader(httpConn.getInputStream(), "UTF-8"));
String line;
// read the returned content
while ((line = in.readLine()) != null) {
result += line;
}
} catch (Exception e) {
e.printStackTrace ();
} finally {
try {
if (in != null) {
in.close();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
return result;
}
/**
* Send POST request
*
* @param url
* Destination address
* @param parameters
* Request parameters, Map type.
* @return remote response result
*/
public static String sendPost(String url, Map<String, String> parameters) {
String result = "";// Returned result
BufferedReader in = null;// Read the response input stream
PrintWriter out = null;
StringBuffer sb = new StringBuffer();// Process request parameters
String params = "";// parameters after encoding
try {
// encode request parameters
if (parameters.size() == 1) {
for (String name : parameters.keySet()) {
sb.append(name).append("=").append(java.net.URLEncoder.encode(parameters.get(name), "UTF-8"));
}
params = sb.toString();
} else {
for (String name : parameters.keySet()) {
sb.append(name).append("=").append(java.net.URLEncoder.encode(parameters.get(name), "UTF-8")).append("&");
}
String temp_params = sb.toString();
params = temp_params.substring(0, temp_params.length() - 1);
}
// create URL object
java.net.URL connURL = new java.net.URL(url);
// open URL connection
java.net.HttpURLConnection httpConn = (java.net.HttpURLConnection) connURL.openConnection();
// set common properties
httpConn.setRequestProperty("Accept", "*/*");
httpConn.setRequestProperty("Connection", "Keep-Alive");
httpConn.setRequestProperty("User-Agent","Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)");
// set the POST method
httpConn.setDoInput(true);
httpConn.setDoOutput(true);
// Get the output stream corresponding to the HttpURLConnection object
out = new PrintWriter(httpConn.getOutputStream());
// send request parameters
out.write(params);
// flush the buffer of the output stream
out.flush();
// Define the BufferedReader input stream to read the response of the URL and set the encoding method
in = new BufferedReader(new InputStreamReader(
httpConn.getInputStream(), "UTF-8"));
String line;
// read the returned content
while ((line = in.readLine()) != null) {
result += line;
}
} catch (Exception e) {
e.printStackTrace ();
} finally {
try {
if (out != null) {
out.close();
}
if (in != null) {
in.close();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
return result;
}