用Java發送POST數據

Question

我試圖用POST提交表單。我想發送一些值並將它們存儲在Web服務器上的一個SQL數據庫中。我在堆棧中發現了這個例子，但是我沒有正確理解它。

URL應該引用接受POST請求的php文件嗎？其他值在這裏我必須考慮。我geuss的參數是好的，他們應該匹配我的PHP文件上的POST檢查。

這是成功發送數據與POST從Java到我的網絡服務器所需的全部嗎？

URL url = new URL("http://g.php"); 
     Map<String,Object> params = new LinkedHashMap<>(); 
     params.put("value", 5); 
     params.put("id", 17); 

     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); 

Answer 1

相同，但註釋：

URL url = new URL("http://g.php"); // URL to your application 
    Map<String,Object> params = new LinkedHashMap<>(); 
    params.put("value", 5); // All parameters, also easy 
    params.put("id", 17); 

    StringBuilder postData = new StringBuilder(); 
    // POST as urlencoded is basically key-value pairs, as with GET 
    // This creates key=value&key=value&... pairs 
    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")); 
    } 

    // Convert string to byte array, as it should be sent 
    byte[] postDataBytes = postData.toString().getBytes("UTF-8"); 

    // Connect, easy 
    HttpURLConnection conn = (HttpURLConnection)url.openConnection(); 
    // Tell server that this is POST and in which format is the data 
    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); 

    // This gets the output from your server 
    Reader in = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8")); 

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