Java HttpClient 4.x 實現 HTTPS POST 請求：忽略證書驗證的完整方案

場景痛點

開發 HTTPS 應用時常遇兩類問題：

1. 測試服務器無有效 SSL 證書 → 拋出 SSLPeerUnverifiedException
2. 有證書但因未知原因仍報錯

解決核心：自定義 TrustManager 接受所有證書。

核心實現代碼

public class HttpClientUtil {
    
    public static void main(String[] args) throws Exception {
        Map<String, String> params = new HashMap<>();
        params.put("TransName", "IQSR");
        params.put("Plain", "transId=IQSR~|~originalOrderId=2012...");
        params.put("Signature", "9b759887e6ca9d4c24509d22ee4d2249...");
        sendSSLPostRequest("https://www.cebbank.com/per/QueryMerchantEpay.do", params);
    }

    @SuppressWarnings("finally")
    public static String sendSSLPostRequest(String reqURL, Map<String, String> params) {
        long responseLength = 0;
        String responseContent = null;
        
        HttpClient httpClient = new DefaultHttpClient();
        
        // 1. 創建信任所有證書的 TrustManager
        X509TrustManager xtm = new X509TrustManager() {
            public void checkClientTrusted(X509Certificate[] chain, String authType) {}
            public void checkServerTrusted(X509Certificate[] chain, String authType) {}
            public X509Certificate[] getAcceptedIssuers() { return null; }
        };

        try {
            // 2. 初始化 SSLContext
            SSLContext ctx = SSLContext.getInstance("TLS");
            ctx.init(null, new TrustManager[]{xtm}, null);
            
            // 3. 創建 SSLSocketFactory 並註冊
            SSLSocketFactory socketFactory = new SSLSocketFactory(ctx);
            httpClient.getConnectionManager().getSchemeRegistry()
                .register(new Scheme("https", 443, socketFactory));
            
            // 4. 構建 POST 請求
            HttpPost httpPost = new HttpPost(reqURL);
            List<NameValuePair> formParams = new ArrayList<>();
            for (Map.Entry<String, String> entry : params.entrySet()) {
                formParams.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
            }
            httpPost.setEntity(new UrlEncodedFormEntity(formParams, "UTF-8"));
            
            // 5. 執行請求並處理響應
            HttpResponse response = httpClient.execute(httpPost);
            HttpEntity entity = response.getEntity();
            
            if (entity != null) {
                responseLength = entity.getContentLength();
                responseContent = EntityUtils.toString(entity, "UTF-8");
                EntityUtils.consume(entity);
            }
            
            System.out.println("請求地址: " + httpPost.getURI());
            System.out.println("響應狀態: " + response.getStatusLine());
            System.out.println("響應長度: " + responseLength);
            System.out.println("響應內容: " + responseContent);
            
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            httpClient.getConnectionManager().shutdown();  // 釋放資源
            return responseContent;
        }
    }
}

關鍵技術點解析

生產環境安全提醒

⚠️ 僅限測試環境使用！ 生產環境必須驗證服務器證書，防止中間人攻擊。正確做法是將服務器 CA 證書導入客戶端信任庫，或使用有效的商業證書。

依賴坐標

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version>
</dependency>