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Sending and receiving of request parameters

2022-07-03 08:45:00 【The corner of fufu】

Catalog

One 、 Request parameters

The request parameter means that the browser sends a request to Tomcat Data submitted
Request parameters are usually data entered by the user , stay Servlet To deal with
Parameter name 1= value 1& Parameter name 2= value 2

Two 、 Send and receive request parameters

html page

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title> Information registration form </title>
</head>
<body>
<h1> Information registration form </h1>
<form action="/FirstServlet/sample">
<table>
	<tr>
		<td> full name ：</td>
		<td><input name="name"/></td>
	</tr>
	<tr>
		<td> Telephone ：</td>
		<td><input name="mobile"/></td>
	</tr>
	<tr>
		<td> Gender ：</td>
		<td>
			<select name="sex">
				<option value="male"> male </option>
				<option value="female"> Woman </option>
			</select>
		</td>
	</tr>
	<tr>
		<td> hobby ：</td>
		<td>
			<input type="checkbox" name="hobby" value="Swimming"/> swimming 
			<input type="checkbox" name="hobby" value="Speech"/> speech 
			<input type="checkbox" name="hobby" value="Reading"/> read 
			<input type="checkbox" name="hobby" value="Program"/> Programming 
		</td>
	</tr>
	<tr>
		<td align="center" colspan="2">
			<input type="submit" value=" Submit ">
		</td>
	</tr>
</table>
</form>
</body>
</html>

java page

package com.imooc.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class SampleServlet extends HttpServlet{
    
	public void service(HttpServletRequest request, HttpServletResponse response) throws IOException {
    
		String name = request.getParameter("name");
		String mobile = request.getParameter("mobile");
		String sex = request.getParameter("sex");
		String[] hobby1 = request.getParameterValues("hobby");
		PrintWriter out = response.getWriter();
		out.println("<h1>information</h1>");
		out.println("<h3>name:"+ name + "</h3>");
		out.println("<h3>mobile:"+ mobile + "</h3>");
		out.println("<h3>sex:"+ sex + "</h3>");
		for(int i=0;i<hobby1.length;i++) {
    
			out.println("<h3>hobby:"+ hobby1[i] + "</h3>");
		}
		out.println("<a href='http://www.baidu.com'>baidu</a>");
	}
}

Submission of request parameters

Output

3、 ... and 、Get and Post request

Get The way is to pass the data in URL Additional data explicitly sends data to the server （ It is often used in query functions that do not contain sensitive information ）
Post The method will store the data in “ Request body ” Send data to the server implicitly （ For functions with high security or servers “ Write ” operation ）

1、 Network data differences

（1）Get request

（2）Post request

2、 The treatment is different , The effect is different

（1）Get request

//  Handle get request 
	public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
    
		String name = request.getParameter("name");
		response.getWriter().println("<h1 style='color:green'>" + name + "</h1>");
	}

<form action=“/FirstServlet/request_method” method=“get”>

（2）Post request

//  Handle post request 
		public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
    
			String name = request.getParameter("name");
			response.getWriter().println("<h1 style='color:red'>" + name + "</h1>");
		}