注意我们在本利中使用BeanUtils类的静态方法populate()将用户输入的登录信息转成到本地的user类中，我们需要注意在login.html几个<input>的name属性需要和user类中的属性的名字要相同。
将用户输入的信息
1、网页显示最原始的登录页面。
2、用户填写了数据后登录后，会连接到服务器。
3、服务器将浏览器用户传来的信息组合到mysql查询语句中发送到mysql进行查询，如果验证了用户名和密码都正确，则显示登录成功，如果验证失败则显示登录失败。
整个项目信息如下：
1、配置文件
druid.properties(放在src目录下)
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql:///demosql
username=root
password=tt1314521
initialSize=5
maxActive=10
maxWait=3000二、登录界面文件
login.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>用户登录</title>
</head>
<body>
<form action="loginS" name="login_in" method="post">
<label for="username">用户名</label><input type="text" name="username" id="username" placeholder="请输入用户名" >
<br>
<label for="password">密码</label><input type="password" name="password" id="password" placeholder="请输入密码">
<br>
<input type="submit" value="提交">
</form>
</body>
</html>3、servlet类文件
（1）、LoginServlet.java,登录
import cn.lw.dao.Daouser;
import cn.lw.domain.User;
import org.apache.commons.beanutils.BeanUtils;
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.lang.reflect.InvocationTargetException;
import java.util.Map;
@WebServlet("/loginS")
public class LoginServlet extends HttpServlet{
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("utf-8");
// String username = req.getParameter("username");
// String password = req.getParameter("password");
//
// User usr_login = new User();
// usr_login.setUser(username);
// usr_login.setPassword(password);
// 采用BeanUtils工具类将浏览器发送的参数放到User类中去
Map<String, String[]> parameterMap = req.getParameterMap();
User user_login = new User();
try {
BeanUtils.populate(user_login,parameterMap);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
Daouser daouser = new Daouser();
User user = daouser.loginUser(user_login);
if (user == null){
req.getRequestDispatcher("failServlet").forward(req,resp);
}else{
req.setAttribute("user",user);
req.getRequestDispatcher("successServlet").forward(req,resp);
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doGet(req,resp);
}
}
(2)、failServlet.java，验证失败跳转
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("/failServlet")
public class failServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("type/html;charset=utf-8");
response.getWriter().write("用户名或密码错误！");
}
}（2）验证成功跳转
import cn.lw.domain.User;
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("/successServlet")
public class successServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
User user = (User) request.getAttribute("user");
if(user != null){
response.setContentType("type/html;charset=utf-8");
response.getWriter().write("登入成功，"+ user.getUser()+"欢迎你！");
}
}
}
用户信息类User.java
public class User {
private int id;
private String username;
private String password;
public User() {
}
public User(int id, String user, String password) {
this.id = id;
this.username = user;
this.password = password;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String user) {
this.username = user;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", user='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
数据库操作：Daouser.java
import cn.lw.domain.User;
import cn.lw.util.JDBCUtils;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
public class Daouser {
private JdbcTemplate jdbcTemplate = new JdbcTemplate(JDBCUtils.getDataSource());
public User loginUser(User user_login){
try {
String sql = "select * from users where user =? and password=?";
User user = jdbcTemplate.queryForObject(sql,
new BeanPropertyRowMapper<User>(User.class),
user_login.getUsername(),user_login.getPassword());
return user;
} catch (DataAccessException e) {
e.printStackTrace();
return null;
}
}
}
