JAVA_WEB之Request

Request

一、试一下

package com.saxon.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class requestDemo extends HttpServlet {
    @Override
    protected void doGet (HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String username = req.getParameter ("username");
        String password = req.getParameter ("password");
        String path = this.getServletContext ().getContextPath ();
        resp.sendRedirect (path+"/success.html");//选择重定向的去处
    }

    @Override
    protected void doPost (HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet (req, resp);
    }
}

<html>
<head>
    <meta charset="UTF-8">

    <title>test</title>
</head>
<body>
<h2>Hello World!</h2>
<%-- pageContext.request.contextPath 当前目录/url pattern --%>
<form action="${pageContext.request.contextPath}/re" method="post">
    <p><label>username：<input type="text" name="username"></label></p>
    <p><label>password：<input type="password" name="password"></label></p>
    <input type="submit">
</form>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1>successful</h1>
</body>
</html>

通过代码实现密码输入，成功跳转成功。

二、获得前端信息

1.接收前端信息

package com.saxon.servlet;


import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Arrays;

//ISO_8859_1 默认编码
public class requestDemo extends HttpServlet {
    @Override
    protected void doGet (HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding ("utf-8");//解决乱码问题
        String username = req.getParameter ("username");
        String[] hobbies = req.getParameterValues ("hobbies");
        System.out.println (Arrays.toString (hobbies));
        String path = this.getServletContext ().getContextPath ();
        resp.sendRedirect (path + "/new.html");//302
        //req.getRequestDispatcher ("/sucess.jsp").forward (req,resp);
        resp.setCharacterEncoding ("utf-8");
    }

    @Override
    protected void doPost (HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet (req, resp);
    }

}

2.提交页

<%@ page contentType="text/html;charset=UTF-8" language="java" %><%解决界面乱码问题%>
<html>
<body>
<h2>Hello World!</h2>
<%--pageContext.request.contextPath 当前目录/url pattern--%>
<form action="${pageContext.request.contextPath}/re" method="post" >
    <p><label>username：<input type="text" name="username"></label></p>
    <p><label>password：<input type="password" name="password"></label></p>
    <p>爱好：
        <input type="checkbox" name="hobbies" value="篮球" required>篮球
        <input type="checkbox" name="hobbies" value="游戏">游戏
        <input type="checkbox" name="hobbies" value="休息">休息
        <input type="checkbox" name="hobbies" value="唱歌">唱歌
    </p>
    <input type="submit">
</form>
</body>
</html>

3.成功反馈,跳出这个界面

<%--
  Created by IntelliJ IDEA.
  User: saxon
  Date: 2020/7/26
  Time: 20:44
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title></title>
</head>
<body>
<h1>successful</h1>
</body>
</html>

关于乱码问题：

1.首先是Tomcat 的问题，如果在界面加载控制台出现乱码，就改logging.properties（java.util.logging.ConsoleHandler.encoding = GBK）最后一个有关编码的UTF-8改成GBK;

2.如果是接收的时候出现数据的乱码，就用request.setCharacterEncoding (“utf-8”);就可以了