Hradyesh Chaturvedi

In Java Spring, constructor-based dependency injection is a way to provide dependencies to a class by passing them in through the constructor. This is done by annotating the constructor with the @Autowired annotation. When a class is instantiated, Spring will automatically call the constructor and pass in any dependencies that have been defined.  

Self-studying Java Spring can be a challenging but rewarding process. Here are a few tips to help you get started:

1. Start with the basics: Before diving into the details of Spring, make sure you have a solid understanding of the Java programming language. Spring is built on top of Java, so it's important to be comfortable with the language before trying to learn the framework.

2. Use online tutorials and documentation: The Spring Framework documentation is a great place to start learning the basics of the framework. Additionally, there are many online tutorials and articles that cover different aspects of Spring and provide examples to help you understand the concepts.

3. Practice and experiment: The best way to learn Spring is by building your own applications. Try to build small projects that implement the features you're learning, and don't be afraid to experiment and try new things.

4. Join a community: There are many online communities, such as forums and social media groups, where developers share their experiences and knowledge about Spring. Joining a community can be a great way to get help when you're stuck and to learn new things from more experienced developers.

5. Take a course or read a book: There are many courses and books available that can help you learn Spring, such as the popular book "Spring in Action" by Craig Walls. These resources can provide a structured learning experience and can be a great way to supplement your self-study.

Remember to take your time, don't get overwhelmed and don't hesitate to seek help if needed. With patience and persistence, you'll be able to master the Spring Framework.

The MEAN stack (MongoDB, Express.js, AngularJS, and Node.js) is becoming more popular in web development because it allows for full-stack JavaScript development, which can make the development process more efficient and streamlined. Additionally, MongoDB's use of JSON-like documents can make data storage and retrieval more flexible and efficient. The JavaScript-based stack also has a wider pool of developers to draw from, as JavaScript is one of the most widely-used programming languages.

Java Spring is a powerful framework for building enterprise-grade applications, but it requires more experienced developers and can be more complex to learn and use. Spring is still a very popular choice for building Java-based web applications, especially in enterprise environments, but the MEAN stack offers a more lightweight and streamlined option for smaller projects and teams.

SomePage.php

<a href="download.php?FileNo=<?echo $FileNo;?>">File Name</a>

download.php

$FileNo=$_GET['FileNO'];

//Use Mysql Query to find the 'full path' of file using $FileNo.
// I Assume $FilePaths as 'Full File Path'.

download_file($FilePaths);

function download_file( $fullPath )
{
  if( headers_sent() )
    die('Headers Sent');


  if(ini_get('zlib.output_compression'))
    ini_set('zlib.output_compression', 'Off');


  if( file_exists($fullPath) )
  {

    $fsize = filesize($fullPath);
    $path_parts = pathinfo($fullPath);
    $ext = strtolower($path_parts["extension"]);

    switch ($ext) 
    {
      case "pdf": $ctype="application/pdf"; break;
      case "exe": $ctype="application/octet-stream"; break;
      case "zip": $ctype="application/zip"; break;
      case "doc": $ctype="application/msword"; break;
      case "xls": $ctype="application/vnd.ms-excel"; break;
      case "ppt": $ctype="application/vnd.ms-powerpoint"; break;
      case "gif": $ctype="image/gif"; break;
      case "png": $ctype="image/png"; break;
      case "jpeg":
      case "jpg": $ctype="image/jpg"; break;
      default: $ctype="application/force-download";
    }

    header("Pragma: public"); 
    header("Expires: 0");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header("Cache-Control: private",false); 
    header("Content-Type: $ctype");
    header("Content-Disposition: attachment; filename=\"".basename($fullPath)."\";" );
    header("Content-Transfer-Encoding: binary");
    header("Content-Length: ".$fsize);
    ob_clean();
    flush();
    readfile( $fullPath );

  } 
  else
    die('File Not Found');

}