无法从 Java 应用程序正确使用 http POST 方法

Question

我正在开发一个 Java 桌面应用程序，该应用程序接受用户输入并使用 HTTP POST 方法针对网站的 API 对其进行验证。如果用户输入的信息与网站的数据库相匹配，该方法将返回 200 OK 的响应代码，允许用户前进到 Java 应用程序的下一页。

    FOR THE CODE TO WORK, TWO INPUT PARAMETERS ARE REQUIRED

    1. license key = Smx22Mar
    2. deviceid = Laptop
    Content Type must be: application/x-www-form-urlencoded     

在通过 Java 应用程序运行 POST 方法之前，我们使用 POSTMAN 验证了此设置，它采用相同的输入，根据数据库检查它并提供 200 OK 的响应代码。

但是当通过Java应用程序提供相同的输入参数时，它返回的响应码是204 No Content found。

整个应用的代码如下：

//FXML 控制器类 包认证；

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.ResourceBundle;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.TextField;


public class FXMLDocumentController implements Initializable {

    @FXML private TextField productKeyField;
    @FXML private TextField deviceIdField;

   @FXML private void Validate(ActionEvent event){

    String authKey=productKeyField.getText();
    String devicetype= deviceIdField.getText();

    boolean serverResponse=getServerKeyStatus(authKey,devicetype);
    System.out.println("Server Response"+serverResponse);

    if(serverResponse){ 
    //THIS IS THE DESIRED OUTPUT,WITH A STATUS OF 200 OK 
    System.out.println("License key is Authorised-------ACCESS GRANTED------");

    try {
    } catch (Exception e) {
    // TODO Auto-generated catch block
    e.printStackTrace(); }
    } else {
    System.out.println("Unauthorized License key");
    }
    }

    public static boolean getServerKeyStatus(String authkey,String devicetype){
    FXMLDocumentController http=new FXMLDocumentController();
    int status_code = 0;
    try {
        System.out.println(" Key is:"+authkey+ " Device Type is "+ devicetype);
        status_code=http.sendPost(authkey,devicetype);
        } catch (Exception e) {
        System.out.println("Exception while license key "+ e.getMessage());
        }
        if(status_code==200){
        //Logic to go to the next page
        return true;
        }
        else{
         System.out.println("Please enter the right KEY to proceed");
        return false;
        }
}


    private int sendPost(String authkey,String devicetype) throws Exception {

        final String USER_AGENT = "Mozilla/5.0";
        int status_code=0;
        try {

        String url = "http://www.example.com/api/software/activate";

        HttpClient client = new DefaultHttpClient();
        HttpPost post = new HttpPost(url);
        post.setHeader("User-Agent", USER_AGENT);
        List<NameValuePair> urlParameters = new ArrayList<>();
        urlParameters.add(new BasicNameValuePair("licensekey",authkey));
        urlParameters.add(new BasicNameValuePair("deviceid",devicetype));

        HttpResponse response = client.execute(post);
        response.setEntity(new UrlEncodedFormEntity(urlParameters));

        System.out.println("\nSending 'POST' request to URL : " + url);
        System.out.println("Post parameters : " + post.getEntity());
        System.out.println("Response Code : " + response.getStatusLine().getStatusCode());
        status_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());
        } catch (Exception e) {
        }
      return status_code;
    }   


    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    }
}

//GUI的FXML代码

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.AnchorPane?>

<AnchorPane id="AnchorPane" prefHeight="200" prefWidth="320" style="-fx-background-color: lightblue;" xmlns="http://javafx.com/javafx/8.0.60" xmlns:fx="http://javafx.com/fxml/1" fx:controller="authentication.FXMLDocumentController">
    <children>
        <Button layoutX="144.0" layoutY="147.0" onAction="#Validate" text="Validate" />
        <Label fx:id="label" layoutX="126" layoutY="120" minHeight="16" minWidth="69" />
      <TextField fx:id="productKeyField" layoutX="121.0" layoutY="52.0" />
      <TextField fx:id="deviceIdField" layoutX="121.0" layoutY="100.0" />
      <Label layoutX="20.0" layoutY="56.0" text="Authorisation key" />
      <Label layoutX="36.0" layoutY="104.0" text="Device type" />
    </children>
</AnchorPane>

//主类

public class Authentication extends Application {

    @Override
    public void start(Stage stage) throws Exception {
        Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));
        Scene scene = new Scene(root);
        stage.setScene(scene);
        stage.show();
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }

}

我是这些 Servlet 方法的新手，因此我无法理解为什么通过 POSTMAN 输入的输入参数有效，而通过 Java 应用程序的 POST 方法调用同样无效。

对于很长的代码和问题，我们深表歉意。请有人指导我哪里出错以及如何解决这个问题。提前致谢。

Answer 1

自从我上次使用这些 Apache 工具后，API 发生了变化。所以我展示的可能不是准确的答案。但在我看来，您确实将参数放入响应而不是帖子中，而且您的操作顺序错误。

不好：

    HttpResponse response = client.execute(post);
    response.setEntity(new UrlEncodedFormEntity(urlParameters));

（可能）好：

    post.setEntity(new UrlEncodedFormEntity(urlParameters));
    HttpResponse response = client.execute(post);

你不妨看看这篇文章 -> Sending HTTP POST Request In Java