Servlet 之 request获取请求参数的通用方式

获取请求参数的通用方式

根据参数获取参数值：
String name = request.getParameter("name");

根据参数获取参数值的数组：
String[] hobbies = request.getParameterValues("hobby");

获取所有请求的参数名称：
Enumeration parameterNames = request.getParameterNames();

获取所有参数的map集合
Map<String,String[]> getParameterMap()；

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Enumeration;

@WebServlet("/RegisterDemo")
public class RegisterDemo extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //通用方法
        //根据参数获取参数值
        String name = request.getParameter("name");

        //根据参数获取参数值的数组
        String[] hobbies = request.getParameterValues("hobby");
        for (String hobby : hobbies) {
            System.out.println(hobby);
        }

        //获取所有请求的参数名称
        Enumeration<String> parameterNames = request.getParameterNames();
        while (parameterNames.hasMoreElements()){
            String name1 = parameterNames.nextElement();
            System.out.print(name1);
            String value = request.getParameter(name1);
            System.out.println(value);
            
        //获取所有参数的map集合
        Map<String, String[]> parameterMap = request.getParameterMap();
        //遍历
        Set<String> keyset = parameterMap.keySet();
        for (String key : keyset) {
            //获取集合中的键和值
            String[] values = parameterMap.get(key);
            System.out.println(key);
            for (String value : values) {
                System.out.println(value);
            }
            System.out.println("-------");

        }

        }

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}

相应的html代码：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>注册</title>

    <form action="/RegisterDemo" method="post">
        <input type="text" placeholder="请输入用户名" name="username"> <br>
        <input type="text" placeholder="请输入密码" name="password"> <br>

        <input type="checkbox" name="hobby" value="game"> 游戏
        <input type="checkbox" name="hobby" value="study"> 学习
        <input type="submit" value="注册">


    </form>
</head>
<body>

</body>
</html>

Servlet 之 request获取请求参数的通用方式

获取请求参数的通用方式

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