Java-发送HTTP参数通过后的方法很容易

StackOverflow https://stackoverflow.com/questions/4205980

题

我成功地使用这个代码发送 HTTP 请求的一些参数通过 GET 方法

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();
}

现在我可能需要发送的参数(即param1,param2,param3)通过 POST 方法，因为他们都非常长。我想添加一个额外的参数，方法(即串httpMethod).

我如何可以改变上述代码尽可能少能够发送参数可以通过 GET 或 POST?

我希望，改变

connection.setRequestMethod("GET");

要

connection.setRequestMethod("POST");

会做的伎俩，但是参数仍然通过得到的方法。

已 HttpURLConnection 有任何方法，这将帮助吗？是否有任何有用的Java构?

任何帮助将非常赞赏。

有帮助吗？

解决方案

在GET请求，参数被作为URL的一部分被发送。

在POST请求，参数作为请求的主体发送，则报头之后。

做一个HttpURLConnection的POST，你需要你已经打开了连接后的参数写入到连接。

此代码应该让你开始：

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 );
}

其他提示

下面是一个简单的例子，然后提交一个表单转储结果页面System.out。改变当然URL和POST PARAMS酌情：

import java.io.*;
import java.net.*;
import java.util.*;

class Test {
    public static void main(String[] args) throws Exception {
        URL url = new URL("http://example.net/new-message.php");
        Map<String,Object> params = new LinkedHashMap<>();
        params.put("name", "Freddie the Fish");
        params.put("email", "fishie@seamail.example.com");
        params.put("reply_to_thread", 10394);
        params.put("message", "Shark attacks in Botany Bay have gotten out of control. We need more defensive dolphins to protect the schools here, but Mayor Porpoise is too busy stuffing his snout with lobsters. He's so shellfish.");

        StringBuilder postData = new StringBuilder();
        for (Map.Entry<String,Object> param : params.entrySet()) {
            if (postData.length() != 0) postData.append('&');
            postData.append(URLEncoder.encode(param.getKey(), "UTF-8"));
            postData.append('=');
            postData.append(URLEncoder.encode(String.valueOf(param.getValue()), "UTF-8"));
        }
        byte[] postDataBytes = postData.toString().getBytes("UTF-8");

        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        conn.setRequestProperty("Content-Length", String.valueOf(postDataBytes.length));
        conn.setDoOutput(true);
        conn.getOutputStream().write(postDataBytes);

        Reader in = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));

        for (int c; (c = in.read()) >= 0;)
            System.out.print((char)c);
    }
}

如果你想要的结果作为String而不是直接打印出来做：

        StringBuilder sb = new StringBuilder();
        for (int c; (c = in.read()) >= 0;)
            sb.append((char)c);
        String response = sb.toString();

我无法得到 Alan的例子真正做到岗位，所以我结束了这一点：

String urlParameters = "param1=a&param2=b&param3=c";
URL url = new URL("http://example.com/index.php");
URLConnection conn = url.openConnection();

conn.setDoOutput(true);

OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());

writer.write(urlParameters);
writer.flush();

String line;
BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));

while ((line = reader.readLine()) != null) {
    System.out.println(line);
}
writer.close();
reader.close();

我觉得真的HttpURLConnection繁琐的使用。你必须写很多的样板，易出错的代码。我需要一个轻量级封装为我的Android项目，并与一个库，你可以使用，以及就出来了： DavidWebb

在上面的例子可以写成这样：

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

可以找到的所提供的链接替代库的列表。

我看到一些其他的答案已经给出了选择，我个人认为，凭直觉你正在做正确的事情）。对不起，在这里devoxx几位发言者已经咆哮着这样的事情。

这就是为什么我个人使用Apache的了HTTPClient / 的HttpCore 库做这样的工作，我觉得他们的API更容易使用比Java的原生HTTP支持。当然情况因人而异！

我已阅读上述答案和已创建了一个实用类来简化HTTP请求。我希望它会帮助你。

方式呼叫 

  // 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);
        }
    });

<强>工具类 

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
 }
}

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();

    }

}

GET和POST方法集像这样...两种类型的对API调用1）得到（）和2）后（）。得到（）方法来获得从API JSON数组值来获得值post（）方法的使用在我们的URL数据后和获得响应。

 public class HttpClientForExample {

    private final String USER_AGENT = "Mozilla/5.0";

    public static void main(String[] args) throws Exception {

        HttpClientExample http = new HttpClientExample();

        System.out.println("Testing 1 - Send Http GET request");
        http.sendGet();

        System.out.println("\nTesting 2 - Send Http POST request");
        http.sendPost();

    }

    // HTTP GET request
    private void sendGet() throws Exception {

        String url = "http://www.google.com/search?q=developer";

        HttpClient client = new DefaultHttpClient();
        HttpGet request = new HttpGet(url);

        // add request header
        request.addHeader("User-Agent", USER_AGENT);

        HttpResponse response = client.execute(request);

        System.out.println("\nSending 'GET' request to URL : " + url);
        System.out.println("Response Code : " + 
                       response.getStatusLine().getStatusCode());

        BufferedReader rd = new BufferedReader(
                       new InputStreamReader(response.getEntity().getContent()));

        StringBuffer result = new StringBuffer();
        String line = "";
        while ((line = rd.readLine()) != null) {
            result.append(line);
        }

        System.out.println(result.toString());

    }

    // HTTP POST request
    private void sendPost() throws Exception {

        String url = "https://selfsolve.apple.com/wcResults.do";

        HttpClient client = new DefaultHttpClient();
        HttpPost post = new HttpPost(url);

        // add header
        post.setHeader("User-Agent", USER_AGENT);

        List<NameValuePair> urlParameters = new ArrayList<NameValuePair>();
        urlParameters.add(new BasicNameValuePair("sn", "C02G8416DRJM"));
        urlParameters.add(new BasicNameValuePair("cn", ""));
        urlParameters.add(new BasicNameValuePair("locale", ""));
        urlParameters.add(new BasicNameValuePair("caller", ""));
        urlParameters.add(new BasicNameValuePair("num", "12345"));

        post.setEntity(new UrlEncodedFormEntity(urlParameters));

        HttpResponse response = client.execute(post);
        System.out.println("\nSending 'POST' request to URL : " + url);
        System.out.println("Post parameters : " + post.getEntity());
        System.out.println("Response Code : " + 
                                    response.getStatusLine().getStatusCode());

        BufferedReader rd = new BufferedReader(
                        new InputStreamReader(response.getEntity().getContent()));

        StringBuffer result = new StringBuffer();
        String line = "";
        while ((line = rd.readLine()) != null) {
            result.append(line);
        }

        System.out.println(result.toString());

    }

}

我有同样的问题。我想通过POST发送数据。 我用下面的代码：

    URL url = new URL("http://example.com/getval.php");
    Map<String,Object> params = new LinkedHashMap<>();
    params.put("param1", param1);
    params.put("param2", param2);

    StringBuilder postData = new StringBuilder();
    for (Map.Entry<String,Object> param : params.entrySet()) {
        if (postData.length() != 0) postData.append('&');
        postData.append(URLEncoder.encode(param.getKey(), "UTF-8"));
        postData.append('=');
        postData.append(URLEncoder.encode(String.valueOf(param.getValue()), "UTF-8"));
    }
    String urlParameters = postData.toString();
    URLConnection conn = url.openConnection();

    conn.setDoOutput(true);

    OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());

    writer.write(urlParameters);
    writer.flush();

    String result = "";
    String line;
    BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));

    while ((line = reader.readLine()) != null) {
        result += line;
    }
    writer.close();
    reader.close()
    System.out.println(result);

我用Jsoup用于解析：

    Document doc = Jsoup.parseBodyFragment(value);
    Iterator<Element> opts = doc.select("option").iterator();
    for (;opts.hasNext();) {
        Element item = opts.next();
        if (item.hasAttr("value")) {
            System.out.println(item.attr("value"));
        }
    }

尝试这种模式：

public static PricesResponse getResponse(EventRequestRaw request) {

    // String urlParameters  = "param1=a&param2=b&param3=c";
    String urlParameters = Piping.serialize(request);

    HttpURLConnection conn = RestClient.getPOSTConnection(endPoint, urlParameters);

    PricesResponse response = null;

    try {
        // POST
        OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());
        writer.write(urlParameters);
        writer.flush();

        // RESPONSE
        BufferedReader reader = new BufferedReader(new InputStreamReader((conn.getInputStream()), StandardCharsets.UTF_8));
        String json = Buffering.getString(reader);
        response = (PricesResponse) Piping.deserialize(json, PricesResponse.class);

        writer.close();
        reader.close();

    } catch (Exception e) {
        e.printStackTrace();
    }

    conn.disconnect();

    System.out.println("PricesClient: " + response.toString());

    return response;
}

public static HttpURLConnection getPOSTConnection(String endPoint, String urlParameters) {

    return RestClient.getConnection(endPoint, "POST", urlParameters);

}


public static HttpURLConnection getConnection(String endPoint, String method, String urlParameters) {

    System.out.println("ENDPOINT " + endPoint + " METHOD " + method);
    HttpURLConnection conn = null;

    try {
        URL url = new URL(endPoint);
        conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod(method);
        conn.setDoOutput(true);
        conn.setRequestProperty("Content-Type", "text/plain");

    } catch (IOException e) {
        e.printStackTrace();
    }

    return conn;
}

在这里，我发jsonobject作为参数//jsonobject={"名称"："撒旦"，"通过"："abc"}//serverUrl="http://192.168.100.12/testing"//host=192.168.100.12 

  public static String getJson(String serverUrl,String host,String jsonobject){

    StringBuilder sb = new StringBuilder();

    String http = serverUrl;

    HttpURLConnection urlConnection = null;
    try {
        URL url = new URL(http);
        urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setDoOutput(true);
        urlConnection.setRequestMethod("POST");
        urlConnection.setUseCaches(false);
        urlConnection.setConnectTimeout(50000);
        urlConnection.setReadTimeout(50000);
        urlConnection.setRequestProperty("Content-Type", "application/json");
        urlConnection.setRequestProperty("Host", host);
        urlConnection.connect();
        //You Can also Create JSONObject here 
        OutputStreamWriter out = new OutputStreamWriter(urlConnection.getOutputStream());
        out.write(jsonobject);// here i sent the parameter
        out.close();
        int HttpResult = urlConnection.getResponseCode();
        if (HttpResult == HttpURLConnection.HTTP_OK) {
            BufferedReader br = new BufferedReader(new InputStreamReader(
                    urlConnection.getInputStream(), "utf-8"));
            String line = null;
            while ((line = br.readLine()) != null) {
                sb.append(line + "\n");
            }
            br.close();
            Log.e("new Test", "" + sb.toString());
            return sb.toString();
        } else {
            Log.e(" ", "" + urlConnection.getResponseMessage());
        }
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (JSONException e) {
        e.printStackTrace();
    } finally {
        if (urlConnection != null)
            urlConnection.disconnect();
    }
    return null;
}

我高度推荐 http请求 建立在apache http api。

对于你的情况，你可以看到的例子：

private static final HttpRequest<String.class> HTTP_REQUEST = 
      HttpRequestBuilder.createPost("http://example.com/index.php", String.class)
           .responseDeserializer(ResponseDeserializer.ignorableDeserializer())
           .build();

public void sendRequest(String request){
     String parameters = request.split("\\?")[1];
     ResponseHandler<String> responseHandler = 
            HTTP_REQUEST.executeWithQuery(parameters);

   System.out.println(responseHandler.getStatusCode());
   System.out.println(responseHandler.get()); //prints response body
}

如果你不感兴趣，在响应的身体

private static final HttpRequest<?> HTTP_REQUEST = 
     HttpRequestBuilder.createPost("http://example.com/index.php").build();

public void sendRequest(String request){
     ResponseHandler<String> responseHandler = 
           HTTP_REQUEST.executeWithQuery(parameters);
}

对于一般发送后的请求 http请求:阅读该文件，并看看我的答案 HTTP POST请求结果的方式String in JAVA, 发送HTTP POST请求在Java, HTTP POST使用JSON在Java

您好请使用这个类来提高你的POST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;
}

此答案涵盖使用定制的Java POJO的POST调用的特定情况。

使用Maven依赖于 GSON 连载我们的Java对象到JSON。

使用下面GSON依赖安装。

<dependency>
  <groupId>com.google.code.gson</groupId>
  <artifactId>gson</artifactId>
  <version>2.8.5</version>
  <scope>compile</scope>
</dependency>

有关那些使用gradle这个可以使用以下

dependencies {
implementation 'com.google.code.gson:gson:2.8.5'
}

使用的其他进口：

import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.*;
import org.apache.http.impl.client.CloseableHttpClient;
import com.google.gson.Gson;

现在，我们可以继续使用通过的阿帕奇 

private CloseableHttpClient httpclient = HttpClients.createDefault();
HttpPost httppost = new HttpPost("https://example.com");

Product product = new Product(); //custom java object to be posted as Request Body
    Gson gson = new Gson();
    String client = gson.toJson(product);

    httppost.setEntity(new StringEntity(client, ContentType.APPLICATION_JSON));
    httppost.setHeader("RANDOM-HEADER", "headervalue");
    //Execute and get the response.
    HttpResponse response = null;
    try {
        response = httpclient.execute(httppost);
    } catch (IOException e) {
        throw new InternalServerErrorException("Post fails");
    }
    Response.Status responseStatus = Response.Status.fromStatusCode(response.getStatusLine().getStatusCode());
    return Response.status(responseStatus).build();

上面的代码将与来自POST调用

接收到的响应代码返回

我把Boann答案，并用它来创建一个更加灵活的查询字符串生成器，支持列表和数组，就如同PHP的http_build_query方法：

public static byte[] httpBuildQueryString(Map<String, Object> postsData) throws UnsupportedEncodingException {
    StringBuilder postData = new StringBuilder();
    for (Map.Entry<String,Object> param : postsData.entrySet()) {
        if (postData.length() != 0) postData.append('&');

        Object value = param.getValue();
        String key = param.getKey();

        if(value instanceof Object[] || value instanceof List<?>)
        {
            int size = value instanceof Object[] ? ((Object[])value).length : ((List<?>)value).size();
            for(int i = 0; i < size; i++)
            {
                Object val = value instanceof Object[] ? ((Object[])value)[i] : ((List<?>)value).get(i);
                if(i>0) postData.append('&');
                postData.append(URLEncoder.encode(key + "[" + i + "]", "UTF-8"));
                postData.append('=');            
                postData.append(URLEncoder.encode(String.valueOf(val), "UTF-8"));
            }
        }
        else
        {
            postData.append(URLEncoder.encode(key, "UTF-8"));
            postData.append('=');            
            postData.append(URLEncoder.encode(String.valueOf(value), "UTF-8"));
        }
    }
    return postData.toString().getBytes("UTF-8");
}

显示，您还必须callconnection.getOutputStream()“至少一次”（以及setDoOutput(true)）为它把它作为一个POST。

因此，所需的最小的代码是：

    URL url = new URL(urlString);
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    //connection.setRequestMethod("POST"); this doesn't seem to do anything at all..so not useful
    connection.setDoOutput(true); // set it to POST...not enough by itself however, also need the getOutputStream call...
    connection.connect();
    connection.getOutputStream().close();

您甚至可以使用在urlString“GET”样式参数，令人惊讶。虽然这可能会混淆的东西。

您还可以使用的NameValuePair 显然。

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