Apache HttpClient JSON 帖子答案

【问题标题】：Apache HttpClient JSON PostApache HttpClient JSON 帖子
【发布时间】：2015-03-14 02:26:08
【问题描述】：

我尝试在应用程序 (SWT/JFace) 中使用 HttpClient 4.4 直接发送 JSON 字符串：

    public String postJSON(String urlToRead,Object o) throws ClientProtocolException, IOException {
    String result="";
    CloseableHttpClient httpClient = HttpClients.createDefault();
    try {
        HttpPost postRequest = new HttpPost(urlToRead);
        postRequest.setHeader("content-type", "application/x-www-form-urlencoded");
        //postRequest.setHeader("Content-type", "application/json");

        //{"mail":"admin@localhost", "password":"xyz"}
        String jsonString=gson.toJson(o);
        StringEntity params =new StringEntity(jsonString);
        params.setContentType("application/json");
        params.setContentEncoding("UTF-8");
        postRequest.setEntity(params);
        ResponseHandler<String> responseHandler = new BasicResponseHandler();
        result = httpClient.execute(postRequest, responseHandler);
    }finally {
        httpClient.close();;
    }
    return result;
}

我尝试使用 $POST 从服务器 (Apache/PHP) 获取响应

$POST 的正确内容应该是：

array("mail"=>"admin@localhost","password"=>"xyz")

当我使用content-type : application/x-www-form-urlencoded时

$POST 内容为：

array( "{"mail":"admin@localhost","password":"xyz"}"=> )

当我使用content-type : application/json时

$POST 为空：array()

有没有办法使用 HttpClient 发布 JSON 字符串，或者我应该使用 ArrayList<NameValuePair> 并将我的对象的每个成员添加到实体中？

【问题讨论】：

标签： json post httpclient

【解决方案1】：

我提出了“NameValuePair”解决方案（不在 cmets 中，答案太长），但我认为 StringEntity 能够理解 JSON，参见 How to POST JSON request using Apache HttpClient? 和那里：HTTP POST using JSON in Java

public String postJSON(String urlToRead,Object o) throws ClientProtocolException, IOException {
    String result="";
    CloseableHttpClient httpClient = HttpClients.createDefault();
    try {
        HttpPost postRequest = new HttpPost(urlToRead);
        postRequest.setHeader("content-type", "application/x-www-form-urlencoded");

        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();

        //{"mail":"admin@localhost", "password":"xyz"}    
        JsonElement elm= gson.toJsonTree(o);
        JsonObject jsonObj=elm.getAsJsonObject();
        for(Map.Entry<String, JsonElement> entry:jsonObj.entrySet()){
            nameValuePairs.add(new BasicNameValuePair(entry.getKey(),entry.getValue().getAsString()));
        }
         postRequest.setEntity(new UrlEncodedFormEntity(nameValuePairs));
        ResponseHandler<String> responseHandler = new BasicResponseHandler();
        result = httpClient.execute(postRequest, responseHandler);
    }finally {
        httpClient.close();;
    }
    return result;
}

这样，$POST 的内容是正确的：array("mail"=>"admin@localhost","password"=>"xyz")

【讨论】：