The relationship between Java Servlet API and JSP
The relationship between Java Servlet API and JSP
Java Servlet API is a technical standard in the Java Enterprise Edition (Java EE). It defines a set of Java class and interfaces for handling HTTP requests and responses on the server side.Java Servlet API allows developers to write dynamic web applications that can interact with the Web client.
At the same time, Javaseerver Pages (JSP) is a dynamic web technology that allows developers to use Java code to embed them into the HTML page.The JSP page can use the function of the Java Servlet API to process the request and generate response, and can better organize and reuse the code by using the Java tag library (JSTL) and custom tags.
There is a close relationship between Java Servlet API and JSP.In a web application, one or more Java Servlets are usually used to process HTTP requests and generate responses.These services can be written based on interfaces provided by the Java Servlet API to use their functions to process HTTP requests.These services then use the JSP page to generate dynamic content.The JSP page can contain Java code and JSP tags. They can interact with Servlet and Java Servlet API, and call the Java code in the Servlet and obtain the results by reposting or included.
Here are examples of using Java Servlet API and JSP:
First, create a Java Servlet class to process HTTP requests and generate response.The Servlet class can inherit HTTPSERVLET and rewrite the Doget () or Dopost () method.In this method, the function of the Java Servlet API can be used to read the request parameters, set the response header, and write the response content.
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class MyServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String name = request.getParameter("name");
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<body>");
out.println("<h1>Hello, " + name + "!</h1>");
out.println("</body>");
out.println("</html>");
}
}
Next, create a JSP page to generate dynamic content and call service.In the JSP page, you can use the Java code and JSP tags to visit the Java code in Java Servlet API and Servlet.
jsp
<%@ page import="javax.servlet.http.*" %>
<html>
<body>
<h1>Welcome to my website!</h1>
<form action="MyServlet" method="GET">
<input type="text" name="name" placeholder="Enter your name">
<input type="submit" value="Submit">
</form>
</body>
</html>
In this example, when the user visits the JSP page in the browser, it will display a page containing a form.When the user fills in and submits a form, the Doget () method in MyServlet will call the request and generate a dynamic response with the user name.
In summary, the Java Servlet API and JSP are in Web development, especially in the Java enterprise version application.The Java Servlet API provides the function of processing HTTP requests and generating response, and JSP allows dynamic content to combine dynamic content with HTML pages, and generate personalized response by interaction with Java Servlet API.
