传统Servlet获取表单数据

最新推荐文章于 2022-05-05 14:59:08 发布

wudinaniya

最新推荐文章于 2022-05-05 14:59:08 发布

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分类专栏： javaEE

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创建一动态web项目

index.jsp:

<%@ 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>Insert title here</title>
</head>
<body>
	<form action="LoginServlet" method="post">
		姓  名:<input type="text" name="name"/><br/>
		密  码:<input type="password" name="password"><br/>
		年  龄:<input type="text" name="age"><br/>
		爱  好:<input type="checkbox" name="hobby" value="smoke">抽烟 
						<input type="checkbox" name="hobby" value="drink">喝酒
						<input type="checkbox" name="hobby" value="head">烫头<br/>
		入职日期:<input type="text" name="hiredate"><br/>
		<input type="submit" value="提交"/>
	</form>
</body>
</html>

LoginServlet:

注意: 使用了注解@WebServlet 就不用再去web.xml中去配置servlet

package com.qx.servlet;

import java.io.IOException;
import java.util.Arrays;

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("/LoginServlet")
public class LoginServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		
		//Map<String, String[]> parameterMap = request.getParameterMap();
		String name = request.getParameter("name");
		System.out.println(name);
		String age = request.getParameter("age");
		System.out.println(age);
		String[] hobby = request.getParameterValues("hobby");
		System.out.println(Arrays.toString(hobby));
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}
}

浏览器中输入请求地址;

点击提交: 会跳转到LoginServlet, 控制台输出结果如下.

可知多选框对应的value为一个数组

若在servlet中对多选框也使用request.getParameter去接值,则只能接到一个值

String hobby = request.getParameter("hobby");

问题:使用request.getParameterMap去接数据,控制台输出结果又是什么样呢?

接下来,重写 LoginServlet , 使用request.getParameterMap去接数据

package com.qx.servlet;

import java.io.IOException;
import java.util.Arrays;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

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("/LoginServlet")
public class LoginServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		
		Map<String, String[]> parameterMap = request.getParameterMap();
		Set<Entry<String,String[]>> entrySet = parameterMap.entrySet();
		for (Entry<String, String[]> entry : entrySet) {
			String key=entry.getKey();
			String[] value = entry.getValue();
			System.out.println(key+"="+Arrays.toString(value));
		}
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}
}

再次去访问index.jsp,提交表单,控制台输出结果为