jsp页面的doGet()方法和doPost()方法
1.新建一个Dynamic Web Project项目，里面新建一个servlet，新建一个jsp，整体的框架结构如下所示：
2.getLengthOrAreaServlet.java文件的代码如下所示：
package 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("/getLengthOrAreaServlet")
public class getLengthOrAreaServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=GBK");
PrintWriter out = response.getWriter();
String l = request.getParameter("length");
String w = request.getParameter("width");
out.println("<html><body>");
double m = 0;
double n = 0;
try {
m = Double.parseDouble(l);
n = Double.parseDouble(w);
out.println("矩形的周长是：" + (m + n) * 2);
} catch (NumberFormatException e) {
out.println("请输入数字字符！");
}
out.println("</html></body>");
}
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=GBK");
PrintWriter out = response.getWriter();
String l = request.getParameter("length");
String w = request.getParameter("width");
out.println("<html><body>");
double m = 0;
double n = 0;
try {
m = Double.parseDouble(l);
n = Double.parseDouble(w);
out.println("矩形的面积是：" + m * n);
} catch (NumberFormatException e) {
out.println("请输入数字字符！");
}
out.println("</html></body>");
}
}
3.login.jsp文件的代码如下所示：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>login.jsp</title> </head> <body> <h2>输入矩形的长和宽，提交给servlet（post方式）求面积：</h2> <form action="getLengthOrAreaServlet" method="get"> 长：<input type="text" name="length"/><br> 宽：<input type="text" name="width"/><br> <input type="submit" value="提交"/> </form> <h2>输入矩形的长和宽，提交给servlet（get方式）求周长：</h2> <form action="getLengthOrAreaServlet" method="post"> 长：<input type="text" name="length"/><br> 宽：<input type="text" name="width"/><br> <input type="submit" value="提交"/> </form> </body> </html>
4.在浏览器里面输入http://localhost:8080/Servlet/login.jsp运行之后得到的结果如下所示：