【JAVA】JSP中通过Get和Post方式传递页面参数（三种方式）。
一、通过FORM（表单）+Get+request.getParameter方式实现页面传参。
1、Login.jsp (登录页)
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>登陆页</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<form id="Form1" name="FormName" action="index.jsp" method="get">
用户名：<input type="text" name="m_username" value="张飞"></br> </br>
密 码：<input type="Password" name="m_password" value="123456"> </br></br>
<input type="submit" value="登陆">
</form>
</body>
</html>
2、index.jsp（接收参数页）
<%@ page language="java" import="java.util.*" pageEncoding="Utf-8" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>主页面</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<p>接收登陆信息如下： </p>
登录名：
<%
String n_username=request.getParameter("m_username"); // 读取login.jsp中输入的用户名，注意对应：m_username
out.println(n_username); // 输出变量
%>
<br> <br>
密码：
<%
String n_password=request.getParameter("m_password"); // 读取login.jsp中输入的密码，注意对应：m_password
out.println(n_password); // 输出变量
%>
<br> <br>
</body>
</html>
二、通过URL地址+Get+request.getParameter方式实现页面传参。
1、login_1.jsp(传递参数页)
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>LOGIN登陆页</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<p>接收登陆信息如下： </p>
<input name="注册" type="button" id="btn1" title="登注册" value="开始传参到index_2.jsp页" onclick="location.href='index_1.jsp?name=张飞&sex=男'" />
</body>
</html>
2、index_1.jsp(接收参数页)
<%@ page language="java" import="java.util.*" pageEncoding="Utf-8" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>JAVA - 主页面</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<p>接收登陆信息如下： </p>
登录名：
<%
String n_username=request.getParameter("name"); // 读取login_1.jsp中输入的用户名name
out.println(n_username); // 输出变量
%>
<br> <br>
密码：
<%
String n_sex=request.getParameter("sex"); // 读取login_1.jsp中输入的密码，注意对应：sex
out.println(n_sex); // 输出变量
%>
</body>
</html>
三、通过request.setAttribute+request.GetAttribute跳转页面传参
说明：除了在HTML中通过<jsp:forward 跳转，还可以通过<% response.sendRedirect(index_1.jsp?name=张飞) %>在JAVA代码中跳转。
1、login_1.jsp(传递参数页)
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>LOGIN登陆页</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<%
// 通过setAttribute和getAttribute往【index_1.jsp】中传参。
request.setAttribute("m_date","2020-10-01");
request.setAttribute("m_time"," 12:00:01");
%>
<jsp:forward page="index_1.jsp"/> <%--跳转到index.jsp页面 --%>
</body>
</html>
2、index_1.jsp(接收参数页，注意：会跳转页面)
<%@ page language="java" import="java.util.*" pageEncoding="Utf-8" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>JAVA - 主页面</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<p>接收登陆信息如下： </p>
登陆时间：<% out.print(request.getAttribute("m_date"));out.print(request.getAttribute("m_time"));%>
</body>
</html>