如何为Apache HttpClient的HttpPost请求设置URL参数？

问题分析 #

你的代码当前是将SMS对象转成Map后通过map.toString()生成字符串作为POST请求体发送，但存在两个可能导致"参数为空"的问题：

1. 如果短信接口要求的是URL查询参数（而非JSON请求体），当前代码完全没有传递URL参数，自然会出现参数为空；
2. 如果接口要求JSON请求体，map.toString()生成的不是标准JSON格式（Java Map的默认输出是{key=value}，而非合法的{"key":"value"}），导致后端无法解析参数，表现为参数为空。

解决方案 #

情况1：接口要求URL查询参数

如果接口需要通过URL传递参数（如http://example.com/sms?phone=13xxxx&content=xxx），使用URIBuilder构建带参数的请求地址：

public void sendSMS(SMS sms) throws IOException, URISyntaxException {
    String auth = smsUsername + ":" + smsPassword;
    byte[] encodedAuth = encodeBase64(auth.getBytes(StandardCharsets.ISO_8859_1));
    
    // 构建带查询参数的URI
    URIBuilder uriBuilder = new URIBuilder(smsEndpoint);
    ObjectMapper oMapper = new ObjectMapper();
    Map<String, Object> paramMap = oMapper.convertValue(sms, Map.class);
    // 将SMS对象的属性逐个添加为URL查询参数
    for (Map.Entry<String, Object> entry : paramMap.entrySet()) {
        uriBuilder.addParameter(entry.getKey(), entry.getValue().toString());
    }
    
    HttpPost post = new HttpPost(uriBuilder.build());
    post.setHeader(HttpHeaders.AUTHORIZATION, "Basic " + new String(encodedAuth));   
    post.setHeader("Accept", "application/json");
    
    try (CloseableHttpClient httpClient = HttpClients.createDefault();
            CloseableHttpResponse response = httpClient.execute(post)) {
        LOGGER.log(Level.INFO, () -> "the response: " + response.toString());
    }
}

情况2：接口要求JSON请求体

如果接口需要接收JSON格式的请求体，修正JSON字符串的生成方式，避免使用map.toString()，直接用ObjectMapper序列化SMS对象为标准JSON：

public void sendSMS(SMS sms) throws IOException {
    String auth = smsUsername + ":" + smsPassword;
    byte[] encodedAuth = encodeBase64(auth.getBytes(StandardCharsets.ISO_8859_1));
    
    ObjectMapper oMapper = new ObjectMapper();    
    // 直接将SMS对象序列化为标准JSON字符串
    String jsonBody = oMapper.writeValueAsString(sms);
    StringEntity params = new StringEntity(jsonBody, StandardCharsets.UTF_8);       

    HttpPost post = new HttpPost(smsEndpoint);
    post.setHeader(HttpHeaders.AUTHORIZATION, "Basic " + new String(encodedAuth));   
    post.setHeader("Accept", "application/json");
    post.setHeader("Content-type", "application/json");
    post.setEntity(params);       
    
    try (CloseableHttpClient httpClient = HttpClients.createDefault();
            CloseableHttpResponse response = httpClient.execute(post)) {
        LOGGER.log(Level.INFO, () -> "the response: " + response.toString());
    }
}

关键说明 #

• 先确认短信接口的参数传递规范：是URL查询参数还是JSON请求体，这是解决问题的核心；
• 若使用JSON请求体，必须保证发送的是标准JSON格式，否则后端无法正确解析。

内容的提问来源于stack exchange，提问作者slema imen