Remember PreparedStatement?

Simple example using PreparedStatement

Miss the good ole' days when interacting with the database was simple, easy to understand SQL statements and a few lines of code?

Select

public static void main(String[] args) throws Exception {
    String driver = "org.apache.derby.jdbc.EmbeddedDriver";
    
    String dbLocation 
        = String.format("./db/Sample");
    
    String connectionUrl =
        String.format("jdbc:derby:%s;create=true;user=sample;password=elpmas",dbLocation);
    
    Class.forName(driver);
    Connection conn = DriverManager.getConnection(connectionUrl);
    StringBuilder sp = new StringBuilder();
    sp.append("select \n");
    sp.append("    integer_value \n");
    sp.append("  , decimal_value \n");
    sp.append("  , varchar_value \n");
    sp.append("  , timestamp_value \n");
    sp.append("from example \n");
    PreparedStatement stmt = conn.prepareStatement(sp.toString());
    
    ResultSet rs = stmt.executeQuery();
    System.out.printf("ResultSet\n");
    while (rs.next()) {
     int i = rs.getInt(1);
     BigDecimal bd = rs.getBigDecimal(2);
     String s = rs.getString(3);
     Timestamp ts = rs.getTimestamp(4);
     
     System.out.printf("%d\t%f\t%s\t%s\n",i,bd,s, ts.toString());
    }

    conn.commit();
    conn.close();        
    System.out.printf("Goodbye\n");
}

Insert

public static void main(String[] args) throws Exception {
    String driver = "org.apache.derby.jdbc.EmbeddedDriver";
    
    String dbLocation 
        = String.format("./db/Sample");
    
    String connectionUrl =
        String.format("jdbc:derby:%s;create=true;user=sample;password=elpmas",dbLocation);
    
    Class.forName(driver);
    Connection conn = DriverManager.getConnection(connectionUrl);
    StringBuilder sp = new StringBuilder();
    sp.append("insert into example ( \n");
    sp.append("    integer_value \n");
    sp.append("  , decimal_value \n");
    sp.append("  , varchar_value \n");
    sp.append("  , timestamp_value \n");
    sp.append(" ) values ( \n");
    sp.append("    ? \n");
    sp.append("  , ? \n");
    sp.append("  , ? \n");
    sp.append("  , ? \n");
    sp.append(" ) \n");
    PreparedStatement stmt = conn.prepareStatement(sp.toString());
    stmt.setInt(1, 19);
    stmt.setBigDecimal(2, new BigDecimal("100.45"));
    stmt.setString(3, "Hello");        
    stmt.setTimestamp(4, new Timestamp(System.currentTimeMillis()));
    
    int cnt = stmt.executeUpdate();
    
    System.out.printf("count = %d\n", cnt);

    conn.commit();
    conn.close();        
    System.out.printf("Goodbye\n");
}

Enjoy!

SSL JNDI Realm for Tomcat Catalina

Using JNDI as an authentication realm for Tomcat is quite common. What's also quite common is communication with the server needs to happen over SSL. In production, certificates are not a problem. In non-production (and especially development) environments, expired, self-signed, and untrusted SSL certificates are the norm. This project is an JNDI Realm for Tomcat Catalina which is designed to accept any SSL certificate, basically bypassing all security provided by certificates. So only use in development environments.

https://github.com/mjremijan/ferris-catalina-jndi-realm

end

Servlet Info WebApp

Ferris Servlet Info WebApp is a simple servlet which dumps a bunch of info about the request, session, init-params, and server machine to the page for troubleshooting purposes.  It also includes an AJAX call back to the server which can be started and stopped with the "Start" and "Stop" buttons and how many seconds between AJAX calls is determined by the number in the input text box.  When the AJAX response is received, the data on the page is replaced by whatever the server sent back.  This WebApp is especially helpful troubleshooting clustered environments.

Clone the Mavenized project from GitHub (https://github.com/mjremijan/ferris-servletinfo). 

Here is what the information on the page looks like (IP address information has been blacked out)