java 實現httpGet Post Put Delete httpsPost請求並返回結果

 /**
     * 向指定URL發送GET方法的請求
     *
     * @param url  發送請求的URL
     * @param param 請求參數，請求參數應該是 name1=value1&name2=value2 的形式。
     * @return URL 所代表遠程資源的響應結果
     */
    public static String sendGet(String url, String param) {
        
        String result = "";
        BufferedReader in = null;
        try {
            String urlNameString = url + "?" + param;
            URL realUrl = new URL(urlNameString);
            // 打開和URL之間的連接
            URLConnection connection = realUrl.openConnection();
            // 設置通用的請求屬性
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            connection.setRequestProperty("timestamp",timestamp);
            connection.setRequestProperty("CompanyCode",CompanyCode);
            connection.setRequestProperty("companyPassword",companyPassword);
            // 建立實際的連接
            connection.connect();
            // 獲取所有響應頭字段
            Map<String, List<String>> map = connection.getHeaderFields();
            // 遍歷所有的響應頭字段
            for (String key : map.keySet()) {
                logger.info(key + "--->" + map.get(key));
            }
            // 定義 BufferedReader輸入流來讀取URL的響應
            in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream(),"utf-8"));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            logger.info("發送GET請求出現異常！" + e);
            e.printStackTrace();
        }
        // 使用finally塊來關閉輸入流
        finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return result;
    }

    /**
     * 向指定 URL 發送POST方法的請求
     * @param url 發送請求的 URL
     * @param param  請求參數，請求參數應該是 name1=value1&name2=value2 的形式。
     * @return 所代表遠程資源的響應結果
     */
    public static String sendPost(String url, String param) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 打開和URL之間的連接
            URLConnection conn = realUrl.openConnection();
            // 設置通用的請求屬性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            conn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
            conn.setRequestProperty("timestamp",timestamp);
            conn.setRequestProperty("CompanyCode",CompanyCode);
            conn.setRequestProperty("companyPassword",companyPassword);
            // 發送POST請求必須設置如下兩行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 獲取URLConnection對象對應的輸出流
            out = new PrintWriter(conn.getOutputStream());
            // 發送請求參數
            out.print(param);
            // flush輸出流的緩衝
            out.flush();
            // 定義BufferedReader輸入流來讀取URL的響應
            in = new BufferedReader(new InputStreamReader(
                    conn.getInputStream(),"utf-8"));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            logger.info("發送 POST 請求出現異常！"+e);
            e.printStackTrace();
        }
        //使用finally塊來關閉輸出流、輸入流
        finally{
            try{
                if(out!=null){
                    out.close();
                }
                if(in!=null){
                    in.close();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }
        return result;
    }
    /**
     * 向指定 URL 發送Put方法的請求
     * @param url 發送請求的 URL
     * @param param  請求參數，
     * @return 所代表遠程資源的響應結果
     */
    public static String sendPut(String url, String param) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 打開和URL之間的連接
            HttpURLConnection  conn = (HttpURLConnection) realUrl.openConnection();
            // 設置通用的請求屬性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            conn.setRequestMethod("PUT");
            conn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
            conn.setRequestProperty("timestamp",timestamp);
            conn.setRequestProperty("CompanyCode",CompanyCode);
            conn.setRequestProperty("companyPassword",companyPassword);
            // 發送POST請求必須設置如下兩行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 獲取URLConnection對象對應的輸出流
            out = new PrintWriter(conn.getOutputStream());
            // 發送請求參數
            out.print(param);
            // flush輸出流的緩衝
            out.flush();
            // 定義BufferedReader輸入流來讀取URL的響應
            in = new BufferedReader(new InputStreamReader(
                    conn.getInputStream(),"utf-8"));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            logger.info("發送 POST 請求出現異常！"+e);
            e.printStackTrace();
        }
        //使用finally塊來關閉輸出流、輸入流
        finally{
            try{
                if(out!=null){
                    out.close();
                }
                if(in!=null){
                    in.close();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }
        return result;
    }
    /**
     * 向指定 URL 發送Put方法的請求
     * @param url 發送請求的 URL
     * @param param  請求參數，
     * @return 所代表遠程資源的響應結果
     */
    public static String sendDelete(String url, String param) {
         String result = "";
         BufferedReader in = null;
         try {
             String urlNameString = url + "?" + param;
             URL realUrl = new URL(urlNameString);
             // 打開和URL之間的連接
             HttpURLConnection connection = (HttpURLConnection) realUrl.openConnection();
             // 設置通用的請求屬性
             connection.setRequestProperty("accept", "*/*");
             connection.setRequestProperty("connection", "Keep-Alive");
             connection.setRequestProperty("user-agent",
                     "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
             connection.setRequestMethod("DELETE");
             connection.setRequestProperty("timestamp",timestamp);
             connection.setRequestProperty("CompanyCode",CompanyCode);
             connection.setRequestProperty("companyPassword",companyPassword);
             // 建立實際的連接
             connection.connect();
             // 獲取所有響應頭字段
             Map<String, List<String>> map = connection.getHeaderFields();
             // 遍歷所有的響應頭字段
             for (String key : map.keySet()) {
                 logger.info(key + "--->" + map.get(key));
             }
             // 定義 BufferedReader輸入流來讀取URL的響應
             in = new BufferedReader(new InputStreamReader(
                     connection.getInputStream(),"utf-8"));
             String line;
             while ((line = in.readLine()) != null) {
                 result += line;
             }
         } catch (Exception e) {
             logger.info("發送DELETE請求出現異常！" + e);
             e.printStackTrace();
         }
         // 使用finally塊來關閉輸入流
         finally {
             try {
                 if (in != null) {
                     in.close();
                 }
             } catch (Exception e2) {
                 e2.printStackTrace();
             }
         }
         return result;

當需要發送https的POST請求時 如果使用上述的POST就會出現

javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target 錯誤 原因是發送https請求需要驗證證書 當不需要驗證證書但是又要發送https請求時如下處理

爲了避免就要另外寫一個專門發送https請求的Post方法  方法如下：

首先自定義一個MyX509TrustManager   實現X509TrustManager就行

import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

import javax.net.ssl.X509TrustManager;


public class MyX509TrustManager implements X509TrustManager {

    @Override
    public void checkClientTrusted(X509Certificate[] arg0, String arg1)
            throws CertificateException {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void checkServerTrusted(X509Certificate[] arg0, String arg1)
            throws CertificateException {
        // TODO Auto-generated method stub
        
    }

    @Override
    public X509Certificate[] getAcceptedIssuers() {
        // TODO Auto-generated method stub
        return null;
    }

}

然後在重新寫POST方法 和上述HTTPpost相差只是多了紅色字體部分 

/**
     * 發送httpsPost請求
     * */
    public static String sendPostHttps(String url, String param) {
        OutputStreamWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 打開和URL之間的連接
            HttpsURLConnection conn = (HttpsURLConnection) realUrl.openConnection();
            // 設置通用的請求屬性
            SSLContext sslContext = SSLContext.getInstance("SSL");
            TrustManager[] tm = { new MyX509TrustManager() };
            // 初始化
            sslContext.init(null, tm, new java.security.SecureRandom());
            // 獲取SSLSocketFactory對象
            SSLSocketFactory ssf = sslContext.getSocketFactory();
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            conn.setRequestProperty("Accept-Charset", "UTF-8");
            conn.setRequestProperty("contentType", "UTF-8");
            conn.setRequestProperty("Content-type", "application/json;charset=UTF-8");
            // 發送POST請求必須設置如下兩行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setSSLSocketFactory(ssf);
            // 獲取URLConnection對象對應的輸出流
            //out = new PrintWriter(conn.getOutputStream());
            out = new OutputStreamWriter(conn.getOutputStream(),"UTF-8");
            // 發送請求參數
            out.write(param);
            // flush輸出流的緩衝
            out.flush();
            // 定義BufferedReader輸入流來讀取URL的響應
            in = new BufferedReader(new InputStreamReader(
                    conn.getInputStream(),"utf-8"));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            logger.info("發送 POST 請求出現異常！"+e);
            e.printStackTrace();
            return null;
        }
        //使用finally塊來關閉輸出流、輸入流
        finally{
            try{
                if(out!=null){
                    out.close();
                }
                if(in!=null){
                    in.close();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }
        return result;

    }

就可以了