New to Servlet

Question

Hi all,
How to read a file from a Servelt and display the contents of that file?
Thanks
Sreenivas

Answer 1

well, it's not that tricky :
1) read your file. Assuming you now the path to the file you wanna read, just do something like :
File f=new File("yourpath");
BufferedReader in =new BufferedReader(new FileInputStream(f));
StringBuffer data=new StringBuffer();
// do a loop that read your file and accumulate the data in the data variable
// see java.io.BufferedInputStream javadoc
// using a StringBuffer is not mandatory, but it's better when accumulating String chunk that simply doing
// string=string+otherString
content=data.toString();NB: you can also look the IO section in the commons package from the jakarta project, they have a class that do read a file to a String, without the loop mess : http://jakarta.apache.org/commons/io/
2) output it
now you have a String named content that old the content of your file, you can send out as a response.
To achieve this, get the writer from the response objet you'll get as a parameter in the doGet/doPut/service (whatever servlet method you use), and writes your data in it :
response.getWriter().write(content);
3) optimize : the backdraft of this way of doing things is that you load the whole file into memory (and it ma be a big file. A better way of doing things would be to output the data as soon as you have read it from the file, and drop the StringBuffer use.
String line;
PrintWriter out=response.getWriter();
while ((line=in.readline()) !=null) {
      out.write(line);