What are the application scenarios of Java Servlet?

Java Servlet can be used for: 1. Dynamic content generation; 2. Data access and processing; 3. Form processing; 4. File upload; 5. Session management; 6. Filter. Example: Create a FormSubmitServlet to handle form submission, taking name and email as parameters, and redirecting to success.jsp.

Application scenarios of Java Servlet

Servlet plays a vital role in Java Web development, which allows developers Use Java code to handle HTTP requests and responses. Some common Servlet application scenarios are listed below:

1. Dynamic content generation:
Servlet can dynamically generate content in formats such as HTML, XML or JSON to create interactive Web page.

2. Data access and processing:
Servlet can access and process data from a database or other data sources, and then present the data to the user in a visual form.

3. Form processing:
Servlet can process data submitted by HTML forms and be used to create, update or delete records in the database.

4. File upload:
Servlet can handle file upload and save it to a specified location on the server.

5. Session management:
Servlet can use the HTTP Session object to temporarily store user-specific information to achieve session management.

6. Filter:
Servlet can act as a filter, intercepting and modifying HTTP requests and responses before or after they are processed.

Practical case:

Create a Servlet to process the data submitted by the form:

import java.io.IOException;
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("/form-submit")
public class FormSubmitServlet extends HttpServlet {

    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String name = req.getParameter("name");
        String email = req.getParameter("email");

        // 使用 name 和 email 逻辑处理表单数据...

        // 重定向到另一个页面
        resp.sendRedirect("/success.jsp");
    }
}

In the HTML form, <form> The </form>action attribute of should be set to /form-submit:

<form action="/form-submit" method="post">
    <input type="text" name="name">
    <input type="email" name="email">
    <input type="submit" value="Submit">
</form>

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