Java ApacheHTTP客户端POST抛出500

我正在尝试使用ApacheHTTP客户端执行POST请求

下面是代码片段

        CloseableHttpClient client = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost("http://xav.com/asd");

        JSONObject jon = new JSONObject();
        jon.put("param", "val");
        jon.put("param2", "val2");

        String json = jon.toString();
        StringEntity entity = new StringEntity(json);
        httpPost.setEntity(entity);
        httpPost.setHeader("Accept", "application/json");
        httpPost.setHeader("Content-type", "application/json");

        CloseableHttpResponse response = client.execute(httpPost);
        BufferedReader rd = new BufferedReader
                (new InputStreamReader(
                response.getEntity().getContent()));

            String line = "";
            while ((line = rd.readLine()) != null) {
                System.out.println(line);
            }
        client.close();

但我有一个500的错误。我可以使用现有的招摇过市UI执行相同的POST请求。我假设我的请求的构造有问题，并且参数没有正确地传递到后端

---

我是否正确创建了POST请求？有没有办法在添加参数后获取实际的URL？

它只起作用，返回404，而不是500

...
<title>Error 404 Document Not Found on http://xav.com/asd</title>
...

下面是我使用的库：

<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.3</version>
</dependency>

<!-- https://mvnrepository.com/artifact/org.json/json -->
<dependency>
    <groupId>org.json</groupId>
    <artifactId>json</artifactId>
    <version>20170516</version>
</dependency>

以下是节目：

package com.stackoverflow;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.json.JSONObject;

public class ApacheHttpClientTest {
    public static void main(String[] args) throws ClientProtocolException, IOException {
        CloseableHttpClient client = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost("http://xav.com/asd");

        JSONObject jon = new JSONObject();
        jon.put("param", "val");
        jon.put("param2", "val2");

        String json = jon.toString();
        StringEntity entity = new StringEntity(json);
        httpPost.setEntity(entity);
        httpPost.setHeader("Accept", "application/json");
        httpPost.setHeader("Content-type", "application/json");

        CloseableHttpResponse response = client.execute(httpPost);
        BufferedReader rd = new BufferedReader
                (new InputStreamReader(
                response.getEntity().getContent()));

            String line = "";
            while ((line = rd.readLine()) != null) {
                System.out.println(line);
            }
        client.close();
    }
}

package com.stackoverflow;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.json.JSONObject;

public class ApacheHttpClientTest {
    public static void main(String[] args) throws ClientProtocolException, IOException {
        CloseableHttpClient client = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost("http://posttestserver.com/post.php");

        JSONObject jon = new JSONObject();
        jon.put("param", "val");
        jon.put("param2", "val2");

        // Returns the original request URI. Please note URI remains 
        // unchanged in the course of request execution and is not 
        // updated if the request is redirected to another location.
        System.out.println("URI: " + httpPost.getURI());
        // URI: http://posttestserver.com/post.php            

        String json = jon.toString();
        StringEntity entity = new StringEntity(json);
        httpPost.setEntity(entity);
        httpPost.setHeader("Accept", "application/json");
        httpPost.setHeader("Content-type", "application/json");

        CloseableHttpResponse response = client.execute(httpPost);
        BufferedReader rd = new BufferedReader
                (new InputStreamReader(
                response.getEntity().getContent()));

            String line = "";
            while ((line = rd.readLine()) != null) {
                System.out.println(line);
            }
        client.close();
    }
}

---

谢谢，请注意，我在这篇文章中使用了一个垃圾URL。所以你会得到404，因为这个网站在我的答案中不存在，我也尝试过：，它得到200。我的建议是，仔细检查您正在使用的库。好的，有没有办法查看由http客户端创建的完整格式的url？不确定您是否需要

httpPost.getURI（）

。（参见更新答案中的第二个示例）

package com.stackoverflow;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.json.JSONObject;

public class ApacheHttpClientTest {
    public static void main(String[] args) throws ClientProtocolException, IOException {
        CloseableHttpClient client = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost("http://posttestserver.com/post.php");

        JSONObject jon = new JSONObject();
        jon.put("param", "val");
        jon.put("param2", "val2");

        // Returns the original request URI. Please note URI remains 
        // unchanged in the course of request execution and is not 
        // updated if the request is redirected to another location.
        System.out.println("URI: " + httpPost.getURI());
        // URI: http://posttestserver.com/post.php            

        String json = jon.toString();
        StringEntity entity = new StringEntity(json);
        httpPost.setEntity(entity);
        httpPost.setHeader("Accept", "application/json");
        httpPost.setHeader("Content-type", "application/json");

        CloseableHttpResponse response = client.execute(httpPost);
        BufferedReader rd = new BufferedReader
                (new InputStreamReader(
                response.getEntity().getContent()));

            String line = "";
            while ((line = rd.readLine()) != null) {
                System.out.println(line);
            }
        client.close();
    }
}