How to download content from HTTPS (Secured) website using Java

I spent lot of time to accomplish downloading a content from HTTPS(secured) website, I couldn't find right place to get enough information to resolve certificate related errors/exceptions while trying to connecting to https website, I thought of documenting all my findings so that others no need to spend time on researching root cause for certificates related information

       

import java.io.BufferedInputStream;
import java.io.FileOutputStream;

import java.net.URL;

import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;


public class HTTPSFileDownload {
    public HTTPSFileDownload() {
        super();
    }

    /**
     *  This method trust all the certificates.
     */
    private void trustAllCertificates() {

        //Manager to trust all certificates
        TrustManager[] trustAllCerts =
            new TrustManager[] { new X509TrustManager() {
                public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                    return null;
                }

                public void checkClientTrusted(java.security.cert.X509Certificate[] certs,
                                               String authType) {
                }

                public void checkServerTrusted(java.security.cert.X509Certificate[] certs,
                                               String authType) {
                }
            } };

        // Activate the new trust manager
        try {
            SSLContext sc = SSLContext.getInstance("SSL");
            sc.init(null, trustAllCerts, new java.security.SecureRandom());
            HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        HTTPSFileDownload s = new HTTPSFileDownload();
        s.trustAllCertificates();
        String https_url = "https://google.com";
        URL url;
        try{
            url = new URL(https_url);
            HttpsURLConnection con = (HttpsURLConnection)url.openConnection();
            BufferedInputStream in = null;
            FileOutputStream fout = null;
            if (con != null) {
                in = new BufferedInputStream(con.getInputStream());
                fout = new FileOutputStream("C:/RKP/httpsFile.csv");

                byte data[] = new byte[1024];
                int count;
                while ((count = in.read(data, 0, 1024)) != -1) {
                    fout.write(data, 0, count);
                }
            }
            
        }catch(Exception ex){
            ex.printStackTrace();
        }
    }
}
       
 

I hope this would helpful

How to read from CSV file and Writes into Oracle Database using Java

This blog explains about reading content from CSV file and writes into Oracle database table using Java

- Below code reads the data from CSV file, Ensure to give absolute path for the fileName

       

     /**
     * This method reads the file content based on given file name
     * File Name should be absolute path.
     * @param fileName
     * @return
     */
    public List readCSVFile(String fileName) {
        List content = new ArrayList();
        try {
            BufferedReader br = new BufferedReader(new FileReader(fileName));
            String strLine = "";
            StringTokenizer st = null;
            int lineNumber = 0, tokenNumber = 0;
            while ((strLine = br.readLine()) != null) {
                content.add(strLine.split(","));
            }
        } catch (Exception fnfe) {
            fnfe.printStackTrace();
        }

        return content;
    }
       
 

- Below code translates the String array to POJO

       

    /**
     * This method convert given String array to CustomerDTO
     * @param fileContent
     * @return
     */
    public List convertArryToDTO(List fileContent) {
        List custList = null;
        CustomerDTO dto = null;
        if (fileContent != null && fileContent.size() > 0) {
            custList = new ArrayList();
            for (String[] row : fileContent) {
                if (row != null) {
                    dto = new CustomerDTO();
                    dto.setFirstName(row[0]);
                    dto.setMiddleName(row[1]);
                    dto.setLastName(row[2]);
                    dto.setCity(row[4]);
                    custList.add(dto);
                }
            }
        }

        return custList;
    }
       
 

- Below code writes to Database

       

      /**
     * dbURL =jdbc:oracle:thin:@server:port:serviceID
     * @return
     */
    private Connection getDBConnection(String dbURL) {
        Connection conn=null;
        try {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            conn =
                DriverManager.getConnection(dbURL, "hr", "hr");
        } catch (Exception cnfe) {
            cnfe.printStackTrace();
        }
        return conn;
    }

    /**
     *
     * @param custList
     * @return
     */
    public String saveCustomersToDB(List custList) {
        String result = null;
        Connection conn=null;
        String dbURL = "jdbc:oracle:thin:@localhost:1521:XE";
        PreparedStatement stmt=null;
        try {
            conn = getDBConnection(dbURL);
            String query = "INSERT INTO CUSTOMER(ID,FNAME,LNAME,CITY) VALUES (?,?,?,?)";
            stmt = conn.prepareStatement(query);
            Random random = new Random();
            for (CustomerDTO customerDTO : custList) {
                stmt.setInt(1, random.nextInt(3400));
                stmt.setString(2, customerDTO.getFirstName());
                stmt.setString(3, customerDTO.getLastName());
                stmt.setString(4, customerDTO.getCity());
                stmt.execute();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if(stmt != null){
                try {
                    stmt.close();
                } catch (SQLException sqle) {
                    sqle.printStackTrace();
                }
            }
            if(conn != null){
                try {
                    conn.close();
                } catch (SQLException sqle) {
                    sqle.printStackTrace();
                }
            }

        }
        return result;
    }
       
 

- Below method retrieves employee information from database based on given employee ID

       

   public List getCustomerList()
  {
  /**
   * This method retrieves employee information based on employee ID
   * @param empID
   * @return
   */
  public EmployeeDTO readEmployeeDetailsFromDB(int empID)
  {
    EmployeeDTO dto = null;
    Connection conn = null;
    PreparedStatement stmt = null;
    String dbURL = "jdbc:oracle:thin:@localhost:1521:XE";
    try
    {
      conn = getDBConnection(dbURL);
      String query = "SELECT EMP_ID,FNAME,LNAME,DESCRIPTION FROM SRC_EMP WHERE EMP_ID= " + empID;
      stmt = conn.prepareStatement(query);
      stmt.execute();
      ResultSet rs = stmt.executeQuery(query);
      while (rs.next())
      {
        dto = new EmployeeDTO();
        String fName = rs.getString("FNAME");
        int supplierID = rs.getInt("EMP_ID");
        String lName= rs.getString("LNAME");
        String desc = rs.getString("DESCRIPTION");
        dto.setId(supplierID);
        dto.setFName(fName);
        dto.setLName(lName);
        dto.setDesc(desc);
      }
    }
    catch (Exception ex)
    {
      ex.printStackTrace();
    }
    return dto;
  }