servlet Archives - Ebhor.com

Java Servlet JSON Response in JSP using Gson

February 18, 2021February 15, 2021 by manish

In Modern web application We get data from server in JSON format and display data in jsp or html page using Front end library or frameworks like Angular, React etc. This is similar for mobile app development. Here we will see how we can get JSON Response from servlet and show in jsp. What is … Read more

ServletConfig to access multiple initial parameter value

November 8, 2019March 4, 2018 by manish

index.html

<!DOCTYPE html>
<html>
    <head>
        <title>Servlet Config get multiple parameters</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
    </head>
    <body>
        <h1>Servlet Config get multiple parameters</h1>
        <a href="get-all-servlet-config">Get All Servlet Config</a>
    </body>
</html>

<!DOCTYPE html>

<html>

<head>

<title>Servlet Config get multiple parameters</title>

</head>

<body>

<h1>Servlet Config get multiple parameters</h1>

<a href="get-all-servlet-config">Get All Servlet Config</a>

</body>

</html>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
    <servlet>
        <servlet-name>ServletConfigMulParam</servlet-name>
        <servlet-class>ebhor.servlet.ServletConfigMulParam</servlet-class>
        <init-param>
            <param-name>PaymentMode</param-name>
            <param-value>Online</param-value>
        </init-param>
        <init-param>
            <param-name>Terms</param-name>
            <param-value>Handle with care. 30 days money back gaurantee</param-value>
        </init-param>
        <init-param>
            <param-name>Discount</param-name>
            <param-value>20 percent</param-value>
        </init-param>
        <init-param>
            <param-name>Coupan</param-name>
            <param-value>GET20PERCENT</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>ServletConfigMulParam</servlet-name>
        <url-pattern>/get-all-servlet-config</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
</web-app>

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">

<servlet-name>ServletConfigMulParam</servlet-name>

<servlet-class>ebhor.servlet.ServletConfigMulParam</servlet-class>

<init-param>

<param-name>PaymentMode</param-name>

<param-value>Online</param-value>

</init-param>

<init-param>

<param-name>Terms</param-name>

<param-value>Handle with care. 30 days money back gaurantee</param-value>

</init-param>

<init-param>

<param-name>Discount</param-name>

<param-value>20 percent</param-value>

</init-param>

<init-param>

<param-name>Coupan</param-name>

<param-value>GET20PERCENT</param-value>

</init-param>

</servlet>

<servlet-mapping>

<servlet-name>ServletConfigMulParam</servlet-name>

<url-pattern>/get-all-servlet-config</url-pattern>

</servlet-mapping>

<session-config>

<session-timeout>

</session-timeout>

</session-config>

</web-app>

ServletConfigMulParam

package ebhor.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ServletConfigMulParam extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        Enumeration<String> params = getServletConfig().getInitParameterNames();
        while (params.hasMoreElements()) {
            String param = params.nextElement();
            String value = getServletConfig().getInitParameter(param);
            out.println("<h2>"+param + ": " + value+"<h2");
        }
    }

}

package ebhor.servlet;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.Enumeration;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class ServletConfigMulParam extends HttpServlet {

@Override

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html");

PrintWriter out = response.getWriter();

Enumeration<String> params = getServletConfig().getInitParameterNames();

while (params.hasMoreElements()) {

String param = params.nextElement();

String value = getServletConfig().getInitParameter(param);

out.println("<h2>"+param + ": " + value+"<h2");

}

Result

Servlet Annotation WebServlet Example

November 8, 2019February 4, 2017 by manish

First example to show Servlet Welcome. For this we have created index.html page on index.html we have created a link. on click at link it will call welcome servlet. Our project directory structure is as below index.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>First page</title>
    </head>
    <body>
        <h1><a href="welcome">Show welcome servlet</a> </h1>
    </body>
</html>

<%@page contentType="text/html" pageEncoding="UTF-8"%>

<!DOCTYPE html>

<html>

<head>

<title>First page</title>

</head>

<body>

<h1><a href="welcome">Show welcome servlet</a> </h1>

</body>

</html>

Welcome.java

package ebhor.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(name = "Welcome", urlPatterns = {"/welcome"})
public class Welcome extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
            out.println("<!DOCTYPE html>");
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Servlet Welcome</title>");
            out.println("</head>");
            out.println("<body>");
            out.println("<h1>Servlet Welcome </h1>");
            out.println("</body>");
            out.println("</html>");
        } finally {
            out.close();
        }
    }

}

package ebhor.servlet;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

@WebServlet(name = "Welcome", urlPatterns = {"/welcome"})

public class Welcome extends HttpServlet {

@Override

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html;charset=UTF-8");

PrintWriter out = response.getWriter();

try {

out.println("<!DOCTYPE html>");

out.println("<html>");

out.println("<head>");

out.println("<title>Servlet Welcome</title>");

out.println("</head>");

out.println("<body>");

out.println("<h1>Servlet Welcome </h1>");

out.println("</body>");

out.println("</html>");

} finally {

out.close();

}

@WebServlet(name = “Welcome”, urlPatterns = {“/welcome”}) here urlPattern maps /welcome to Welcome.java. <a href=”welcome”>Show welcome … Read more