我成功地使用这段代码通过GET方法发送带有一些参数的HTTP请求

void sendRequest(String request)
{
    // i.e.: request = "http://example.com/index.php?param1=a&param2=b&param3=c";
    URL url = new URL(request); 
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();           
    connection.setDoOutput(true); 
    connection.setInstanceFollowRedirects(false); 
    connection.setRequestMethod("GET"); 
    connection.setRequestProperty("Content-Type", "text/plain"); 
    connection.setRequestProperty("charset", "utf-8");
    connection.connect();
}

现在我可能需要通过POST方法发送参数(即param1, param2, param3),因为它们非常长。 我想添加一个额外的参数,该方法(即字符串httpMethod)。

我怎样才能尽可能少地更改上面的代码,以便能够通过GET或POST发送参数?

我希望情况会有所改变

connection.setRequestMethod("GET");

to

connection.setRequestMethod("POST");

可以完成这个任务,但是参数仍然通过GET方法发送。

HttpURLConnection有任何方法可以帮助吗? 有什么有用的Java构造吗?

任何帮助都将不胜感激。


当前回答

我发现HttpURLConnection使用起来非常麻烦。你必须写大量样板,容易出错的代码。我需要一个轻量级的包装为我的Android项目,并提出了一个库,你可以使用:DavidWebb。

上面的例子可以这样写:

Webb webb = Webb.create();
webb.post("http://example.com/index.php")
        .param("param1", "a")
        .param("param2", "b")
        .param("param3", "c")
        .ensureSuccess()
        .asVoid();

您可以在提供的链接上找到备选库的列表。

其他回答

import java.net.*;

public class Demo{

  public static void main(){

       String data = "data=Hello+World!";
       URL url = new URL("http://localhost:8084/WebListenerServer/webListener");
       HttpURLConnection con = (HttpURLConnection) url.openConnection();
       con.setRequestMethod("POST");
       con.setDoOutput(true);
       con.getOutputStream().write(data.getBytes("UTF-8"));
       con.getInputStream();

    }

}

在GET请求中,参数作为URL的一部分发送。

在POST请求中,参数作为请求体发送,位于请求头之后。

要使用HttpURLConnection进行POST,需要在打开连接后将参数写入连接。

这段代码应该让你开始:

String urlParameters  = "param1=a&param2=b&param3=c";
byte[] postData       = urlParameters.getBytes( StandardCharsets.UTF_8 );
int    postDataLength = postData.length;
String request        = "http://example.com/index.php";
URL    url            = new URL( request );
HttpURLConnection conn= (HttpURLConnection) url.openConnection();           
conn.setDoOutput( true );
conn.setInstanceFollowRedirects( false );
conn.setRequestMethod( "POST" );
conn.setRequestProperty( "Content-Type", "application/x-www-form-urlencoded"); 
conn.setRequestProperty( "charset", "utf-8");
conn.setRequestProperty( "Content-Length", Integer.toString( postDataLength ));
conn.setUseCaches( false );
try( DataOutputStream wr = new DataOutputStream( conn.getOutputStream())) {
   wr.write( postData );
}

我已经阅读了上面的答案,并创建了一个实用工具类来简化HTTP请求。我希望它能帮助你。

方法调用

  // send params with Hash Map
    HashMap<String, String> params = new HashMap<String, String>();
    params.put("email","me@example.com");
    params.put("password","12345");

    //server url
    String url = "http://www.example.com";

    // static class "HttpUtility" with static method "newRequest(url,method,callback)"
    HttpUtility.newRequest(url,HttpUtility.METHOD_POST,params, new HttpUtility.Callback() {
        @Override
        public void OnSuccess(String response) {
        // on success
           System.out.println("Server OnSuccess response="+response);
        }
        @Override
        public void OnError(int status_code, String message) {
        // on error
              System.out.println("Server OnError status_code="+status_code+" message="+message);
        }
    });

实用程序类

import java.io.*;
import java.net.*;
import java.util.HashMap;
import java.util.Map;
import static java.net.HttpURLConnection.HTTP_OK;

public class HttpUtility {

 public static final int METHOD_GET = 0; // METHOD GET
 public static final int METHOD_POST = 1; // METHOD POST

 // Callback interface
 public interface Callback {
  // abstract methods
  public void OnSuccess(String response);
  public void OnError(int status_code, String message);
 }
 // static method
 public static void newRequest(String web_url, int method, HashMap < String, String > params, Callback callback) {

  // thread for handling async task
  new Thread(new Runnable() {
   @Override
   public void run() {
    try {
     String url = web_url;
     // write GET params,append with url
     if (method == METHOD_GET && params != null) {
      for (Map.Entry < String, String > item: params.entrySet()) {
       String key = URLEncoder.encode(item.getKey(), "UTF-8");
       String value = URLEncoder.encode(item.getValue(), "UTF-8");
       if (!url.contains("?")) {
        url += "?" + key + "=" + value;
       } else {
        url += "&" + key + "=" + value;
       }
      }
     }

     HttpURLConnection urlConnection = (HttpURLConnection) new URL(url).openConnection();
     urlConnection.setUseCaches(false);
     urlConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); // handle url encoded form data
     urlConnection.setRequestProperty("charset", "utf-8");
     if (method == METHOD_GET) {
      urlConnection.setRequestMethod("GET");
     } else if (method == METHOD_POST) {
      urlConnection.setDoOutput(true); // write POST params
      urlConnection.setRequestMethod("POST");
     }

     //write POST data 
     if (method == METHOD_POST && params != null) {
      StringBuilder postData = new StringBuilder();
      for (Map.Entry < String, String > item: params.entrySet()) {
       if (postData.length() != 0) postData.append('&');
       postData.append(URLEncoder.encode(item.getKey(), "UTF-8"));
       postData.append('=');
       postData.append(URLEncoder.encode(String.valueOf(item.getValue()), "UTF-8"));
      }
      byte[] postDataBytes = postData.toString().getBytes("UTF-8");
      urlConnection.setRequestProperty("Content-Length", String.valueOf(postDataBytes.length));
      urlConnection.getOutputStream().write(postDataBytes);

     }
     // server response code
     int responseCode = urlConnection.getResponseCode();
     if (responseCode == HTTP_OK && callback != null) {
      BufferedReader reader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
      StringBuilder response = new StringBuilder();
      String line;
      while ((line = reader.readLine()) != null) {
       response.append(line);
      }
      // callback success
      callback.OnSuccess(response.toString());
      reader.close(); // close BufferReader
     } else if (callback != null) {
      // callback error
      callback.OnError(responseCode, urlConnection.getResponseMessage());
     }

     urlConnection.disconnect(); // disconnect connection
    } catch (IOException e) {
     e.printStackTrace();
     if (callback != null) {
      // callback error
      callback.OnError(500, e.getLocalizedMessage());
     }
    }
   }
  }).start(); // start thread
 }
}

现在我要做一个HTTP请求类,它可能不是最有效的类,但它可以工作。 我从这个页面中收集了一些代码,并使其更加动态。

任何需要完整代码的人,我在下面附上了它。 关于如何使用它的示例,您可以查看main方法。

此外,如果你愿意改进在线课程,非常欢迎你来帮助我使这门课变得更好。

import java.net.*;
import java.util.*;
import java.nio.charset.*;
import java.io.*;
  
public class HttpRequest {
    
    
    String result = "";
    
    HttpRequest(String _url, String _method, Map<String, String> _postData, String _contentType) {
        
        try {
            URL url = new URL( _url );
            URLConnection con = url.openConnection();
            HttpURLConnection http = (HttpURLConnection)con;
            http.setRequestMethod(_method); // PUT is another valid option
            http.setDoOutput(true);         
            
            StringJoiner sj = new StringJoiner("&");
            for(Map.Entry<String,String> entry : _postData.entrySet())
                sj.add(URLEncoder.encode(entry.getKey(), "UTF-8") + "=" + entry.getValue());
                //sj.add(URLEncoder.encode(entry.getKey(), "UTF-8") + "=" + URLEncoder.encode(entry.getValue()));
            byte[] out = sj.toString().getBytes(StandardCharsets.UTF_8);
            int length = out.length;
            http.setFixedLengthStreamingMode(length);
            http.setRequestProperty("Content-Type", _contentType);
            http.setRequestProperty( "charset", "utf-8");
            http.setRequestProperty( "Content-Length", Integer.toString( length ));
            http.setInstanceFollowRedirects( false );
            http.setUseCaches( false );
            http.connect();
            try(OutputStream os = http.getOutputStream()) {
                os.write(out);
            }
            if (http.getResponseCode() == HttpURLConnection.HTTP_OK) {
                try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(http.getInputStream()))) {
                String line;
                while ((line = bufferedReader.readLine()) != null) {
                  result = result + line;
                }
            }
          } else {
            System.out.println("Bad response!");
          }
        }catch (IOException e) {
            // writing exception to log
            e.printStackTrace();
        }
        
    }
    
    
    HttpRequest(String _url, String _method, Map<String, String> _postData) {
        this(_url, _method, _postData, "text/html");
    }
    
    HttpRequest(String _url, String _method) {
        this(_url, _method, new HashMap<String, String>());
    }
    
    HttpRequest(String _url) {
        this(_url, "GET");
    }
    
    
    public String toString() {
        return result;
    }
    
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Map<String, String> postData = new HashMap<String, String>();
        postData.putIfAbsent("email", "test@test.com");
        postData.putIfAbsent("password", "test");
        
        HttpRequest result = new HttpRequest("https://httpbin.org/anything", "POST", postData, "application/x-www-form-urlencoded");
        System.out.println(result.toString());
    }
}

你好,请使用这个类来改善你的张贴方法

public static JSONObject doPostRequest(HashMap<String, String> data, String url) {

    try {
        RequestBody requestBody;
        MultipartBuilder mBuilder = new MultipartBuilder().type(MultipartBuilder.FORM);

        if (data != null) {


            for (String key : data.keySet()) {
                String value = data.get(key);
                Utility.printLog("Key Values", key + "-----------------" + value);

                mBuilder.addFormDataPart(key, value);

            }
        } else {
            mBuilder.addFormDataPart("temp", "temp");
        }
        requestBody = mBuilder.build();


        Request request = new Request.Builder()
                .url(url)
                .post(requestBody)
                .build();

        OkHttpClient client = new OkHttpClient();
        Response response = client.newCall(request).execute();
        String responseBody = response.body().string();
        Utility.printLog("URL", url);
        Utility.printLog("Response", responseBody);
        return new JSONObject(responseBody);

    } catch (UnknownHostException | UnsupportedEncodingException e) {

        JSONObject jsonObject=new JSONObject();

        try {
            jsonObject.put("status","false");
            jsonObject.put("message",e.getLocalizedMessage());
        } catch (JSONException e1) {
            e1.printStackTrace();
        }
        Log.e(TAG, "Error: " + e.getLocalizedMessage());
    } catch (Exception e) {
        e.printStackTrace();
        JSONObject jsonObject=new JSONObject();

        try {
            jsonObject.put("status","false");
            jsonObject.put("message",e.getLocalizedMessage());
        } catch (JSONException e1) {
            e1.printStackTrace();
        }
        Log.e(TAG, "Other Error: " + e.getLocalizedMessage());
    }
    return null;
}