HttpClient是目前我們通訊組件中最常見的一個Api了吧。至少從我目前接觸到與外部系統通訊的話是這樣的。下面我將我自己常用的一些知識總結一下。

因為本猿也是邊寫邊總結，有啥不對的還望多多指出。

1：利用httpClient發送https請求。

第一次遇到這種情況是開發與微信支付的接口。適用情形https請求，報文格式：字符串（包含json字符串和xml字符串）。

public String doPost(String url,String charset,String reqXmlData){
??HttpClient httpClient = null;
??HttpPost httpPost = null;
??String result = null;
??try{
???//這里是關鍵，SSLClient繼承了DefaultHttpClient 忽略https校驗過程。SSLClient具體如下。
???httpClient = new SSLClient();
???logger.info("call weixin pay url："+url);
???httpPost = new HttpPost(url);
???logger.info("call weixin pay requestXmlData："+reqXmlData);
???//設置最簡單的字符串請求參數
???StringEntity strEntity = new StringEntity(reqXmlData, charset);
???httpPost.setEntity(strEntity);
???HttpResponse response = httpClient.execute(httpPost);
???int code = response.getStatusLine().getStatusCode();???
???if(code == 200){
????HttpEntity resEntity = response.getEntity();
????if(resEntity != null){
?????result = EntityUtils.toString(resEntity,charset);
????}
???}else{
????//這里就不對其他code處理了
???}
???logger.info("call weixin pay responseXmlData："+result);
??}catch(Exception ex){
???ex.printStackTrace();
??}finally{
???if (httpClient != null){
????httpClient = null;
???}
??}
??return result;
?}

/**
?* 用于進行Https請求的HttpClient
?*/
public class SSLClient extends DefaultHttpClient{
?public SSLClient() throws Exception{
??????? super();
??????? SSLContext ctx = SSLContext.getInstance("TLS");
??????? X509TrustManager tm = new X509TrustManager() {
??????????????? @Override
??????????????? public void checkClientTrusted(X509Certificate[] chain,
??????????????????????? String authType) throws CertificateException {
??????????????? }
??????????????? @Override
??????????????? public void checkServerTrusted(X509Certificate[] chain,
??????????????????????? String authType) throws CertificateException {
??????????????? }
??????????????? @Override
??????????????? public X509Certificate[] getAcceptedIssuers() {
??????????????????? return null;
??????????????? }
??????? };
??????? ctx.init(null, new TrustManager[]{tm}, null);
??????? SSLSocketFactory ssf = new SSLSocketFactory(ctx,SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
??????? ClientConnectionManager ccm = this.getConnectionManager();
??????? SchemeRegistry sr = ccm.getSchemeRegistry();
??????? sr.register(new Scheme("https", 443, ssf));
??? }
}

?

好了，今天就先更新到這里了。下班肥家。20151207

?

?

第二點：利用httpclient來模擬表單提交（兼容http請求和https請求）

相信有很多人遇到過和我一樣的情形，與外部系統對接時。經常是測試環境使用的是http請求而生產正式環境則是https請求。這時候我是這樣做的。

public static String httpPost(String reqUrl, BaseDto baseDto){
??DefaultHttpClient httpclient = new DefaultHttpClient();
??String result = "";
???try {
????if(reqUrl.startsWith("https")){
?????logger.debug("請求地址為https請求");
?????httpclient = new SSLClient();
????}

　//設置超時時間
????httpclient.getParams().setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, TIME_OUT * 1000);
????httpclient.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT, TIME_OUT * 1000);
????HttpPost httppost = new HttpPost(reqUrl);
????logger.debug("調用地址"+reqUrl);

????//定義一個用來存儲表單數據的集合
????List<BasicNameValuePair> formParams = new ArrayList<BasicNameValuePair>();
????formParams.add(new BasicNameValuePair("merchant_id", baseDto.getMerchant_id()));
????formParams.add(new BasicNameValuePair("key_enc", baseDto.getKey_enc()));
????formParams.add(new BasicNameValuePair("sign", baseDto.getSign()));
????formParams.add(new BasicNameValuePair("xml_enc", baseDto.getXml_enc()));

????//UrlEncodedFormEntity與StringEntity相比較的話只能接受鍵值對的形式，試用與表單提交
????HttpEntity entity = new UrlEncodedFormEntity(formParams, "UTF-8");
????httppost.setEntity(entity);
????HttpResponse response=httpclient.execute(httppost);
????int httpCode = response.getStatusLine().getStatusCode();
????logger.debug("返回的code："+httpCode);
????switch (httpCode) {
????case 200:
?????HttpEntity resEntity=response.getEntity();
?????result = EntityUtils.toString(resEntity,"UTF-8");
?????logger.debug("通訊原始結果："+result);
?????return result;
????case 401:
?????logger.debug("請求要求進行身份驗證");
????case 403:
?????logger.debug("請求被拒絕，請檢查IP地址是否已經加入對方白名單");
????case 404:
?????logger.debug("未找到，服務器找不到請求的地址");
????case 405:
?????logger.debug("方法不允許，請確認是否為POST請求方式");
????case 500:
?????logger.debug("查詢請求失敗，內部錯誤");
????default:
?????logger.debug("未知的返回碼：" + httpCode);
????}
???}? catch (Exception e) {
????e.printStackTrace();
????throw new ServiceException(e,"0006","獲取渠道返回信息失敗了，可能是超時了");
???}
?}

好了，今天就先更新到這里了，后面繼續來整理利用httpclient來進行爬蟲。httpclient的超時設置等等。20151208

轉載于:https://www.cnblogs.com/hisunhyx/p/5027419.html

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