Examples of Servlet Filter

by Online Tutorials Library July 14, 2022

Useful Filter Examples

There is given some useful examples of filter.

Example of sending response by filter only

MyFilter.java

  import java.io.*; import javax.servlet.*;  public class MyFilter implements Filter{ public void init(FilterConfig arg0) throws ServletException {}  public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {  PrintWriter out=res.getWriter();  out.print(“<br/>this site is underconstruction..”); out.close();  } public void destroy() {} }   

Example of counting number of visitors for a single page

MyFilter.java

  import java.io.*; import javax.servlet.*;  public class MyFilter implements Filter{ static int count=0; public void init(FilterConfig arg0) throws ServletException {}  public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {  PrintWriter out=res.getWriter(); chain.doFilter(request,response);  out.print(“<br/>Total visitors “+(++count)); out.close();  } public void destroy() {} }   

Example of checking total response time in filter

MyFilter.java

  import java.io.*; import javax.servlet.*;  public class MyFilter implements Filter{ static int count=0; public void init(FilterConfig arg0) throws ServletException {}  public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {  PrintWriter out=res.getWriter(); long before=System.currentTimeMillis();  chain.doFilter(request,response);  long after=System.currentTimeMillis(); out.print(“<br/>Total response time “+(after-before)+” miliseconds”); out.close();  } public void destroy() {} }   

Next TopicServletInputStream Class

Examples of Servlet Filter

Useful Filter Examples

Example of sending response by filter only

Example of counting number of visitors for a single page

Example of checking total response time in filter

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