简单的前台传递后台的列子
作者：互联网
首先需要导入jar包，导入的jar包如下图：
在web——>web-INF 点击右击new 点击Directory 名字名为lib——>lib赋值进入如下jar包后一定右击 Add as Directory as. 加入所创建的项目道中
index.jsp
<%–
Created by IntelliJ IDEA.
User: love
Date: 2020/2/28
Time: 9:18
To change this template use File | Settings | File Templates.
–%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<body>
<%-- form 是表单 有from才可以实现提交行为
action 传递到那里去
method 提交的方法
|--- get : 【默认】
1.会将你的用户和密码（或者是别的数据），裸露在浏览器的地址中，
2.（前台提交）后台提交的非常快
3. 容量有限
|--- post：
1.会将你的用户和密码（或者是背的数据）没有体现在浏览器的地址中（安全）
2.提交没有get快
3.理论上时无限的--%>
<form action="/userServlet" method="post">
<%-- table ：表格 border ： 边 1 px width ：宽 400 px --%>
<table border="1px" width="400px">
<%-- <tr> 定义表的行 <td>定义表的单元--%>
<tr>
<td>用户名：</td>
<td>
<%-- input :输入 type：类型 =“文本档” 名字--%>
<input type="text" name="username">
</td>
</tr>
<tr>
<td>密码：</td>
<td>
<input type="text" name="password">
</td>
</tr>
<tr>
<%-- colspan 合并列
rowspan 合并行
Value 值--%>
<td colspan="2">
<input type="submit" value="登录">
</td>
</tr>
</table>
</form>
</body>
</html>
success.jsp
<%--
Created by IntelliJ IDEA.
User: love
Date: 2020/3/1
Time: 14:34
To change this template use File | Settings | File Templates.
--%>
<%@ page
contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>成功</title>
</head>
<body>
<h2>我已接受到了你的用户名称；${user.username}</h2>
</body>
</html>
web——web-INF——web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
3.<servlet-name>UserServlet</servlet-name>
4. <servlet-class>cn.javabs.houtai.UserServlet</servlet-class>
</servlet>
<servlet-mapping>
2. <servlet-name>UserServlet</servlet-name>
1. <url-pattern>/userServlet</url-pattern>
</servlet-mapping>
</web-app>
UserServlet.java
package cn.javas.houtai;
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;
@WebServlet("/userServlet")
public class UserServlet extends HttpServlet {
UserDao userDao = new UserDao();
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 获取前台数据
String username = request.getParameter("username");
String password = request.getParameter("password");
User user = userDao.login(username,password);
request.setAttribute("user",user);
request.getRequestDispatcher("/success.jsp").forward(request,response);
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}
UserDao.java
package cn.javas.houtai;
mport com.mysql.jdbc.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class UserDao {
Connection conn = (Connection) JdbcUtil.getConnection();
public User login(String username, String password) {
try {
String sql = "select *from user where username = ? and possword = ?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setString(1, username);
ps.setString(2, password);
System.out.println("ps:" + ps);
ResultSet resultSet = ps.executeQuery();
User user = new User();
while (resultSet.next()) {
int id = resultSet.getInt("id");
String name = resultSet.getString("username");
String pwd = resultSet.getString("password");
String sex = resultSet.getString("sex");
String email = resultSet.getString("email");
String role = resultSet.getString("role");
user.setId(id);
user.getName(name);
user.getPassword(password);
user.getSex(sex);
user.getEmail(email);
user.getRole(role);
}
return user;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
JdbcUtils.java
package cn.javas.houtai;
import java.sql.Connection;
import java.sql.DriverManager;
public class JdbcUtil {
public static Connection getConnection() {
String driver = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql:localhost:3306/day28"; // jdbc:mysql://127.0.01:3306/day28 | jdbc:mysql:///day28
String username = "root";
String password = "root";
try {
Class.forName(driver);
Connection connection = DriverManager.getConnection(url, username, password);
} catch (Exception e) {
throw new RuntimeException(e);
}
return null;
}
}
User.java
package cn.javas.houtai;
public class User {
// 私有化 数据类型 变量名称
private int id;
private String name;
private String password;
private String sex;
private String email;
// role 角色
private String role;
// 快捷键 alt+insert 生成getter和setting方法
// tostring方法等方法
public User() {
super();
}
@Override
public int hashCode() {
return super.hashCode();
}
public User(String name, String password, String sex, String email, String role) {
this.name = name;
this.password = password;
this.sex = sex;
this.email = email;
this.role = role;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
", password='" + password + '\'' +
", sex='" + sex + '\'' +
", email='" + email + '\'' +
", role='" + role + '\'' +
'}';
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName(String name) {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public String getPassword(String password) {
return this.password;
}
public void setPassword(String password) {
this.password = password;
}
public String getSex(String sex) {
return this.sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getEmail(String email) {
return this.email;
}
public void setEmail(String email) {
this.email = email;
}
public String getRole(String role) {
return this.role;
}
public void setRole(String role) {
this.role = role;
}
}
General :通用
Request URL：请求路径
http//locathost:8888/day28/userSerlet
本地主机：端口号/ 项目名称/访问路径
Request method: post 请求的方式
status code：200 可以通行
Response Headers ：响应头
Request Headers：请求头
Form Headers ：表单数据
username：wangcai
password：admin123
加燕
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标签：String,sex,email,role,前台,列子,后台,password,public 来源： https://blog.csdn.net/m0_46207738/article/details/104591531