servlet连接数据库，登陆用户

不念不忘少年蓝@ 2023-06-20 10:46 44阅读 0赞

## servlet连接数据库，登陆用户 ##

配置jdbc:  
jdbc.driver=com.mysql.jdbc.Driver  
jdbc.url=jdbc:mysql:///test  
jdbc.user=root  
jdbc.pwd=123456  
创建实体类  
/\*\*  
\*  
\*/  
package domain;

/\*\*

*  @author xiao
 *

\*/  
public class User \{  
private int uid;  
private String uname;  
private String pwd;  
public int getUid() \{  
return uid;  
\}  
public void setUid(int uid) \{  
this.uid = uid;  
\}  
public String getUname() \{  
return uname;  
\}  
public void setUname(String uname) \{  
this.uname = uname;  
\}  
public String getPwd() \{  
return pwd;  
\}  
public void setPwd(String pwd) \{  
this.pwd = pwd;  
\}  
@Override  
public String toString() \{  
return “User \[uid=” + uid + “, uname=” + uname + “, pwd=” + pwd + “\]”;  
\}

\}  
加载驱动  
package utils;

import java.io.IOException;  
import java.io.InputStream;  
import java.sql.Connection;  
import java.sql.DriverManager;  
import java.sql.SQLException;  
import java.util.Properties;

import javax.sql.DataSource;

public class JdbcUtils \{  
public static final DataSource getConnection = null;  
private static String driverClass;  
private static String url;  
private static String user;  
private static String pwd;

static {
    	//获取类加载器，目的读取配置文件
    	InputStream is = JdbcUtils.class.getClassLoader().getResourceAsStream("jdbc.properties");
    	
    	//使用Properties类
    	Properties prop = new Properties();
    	try {
    		prop.load(is);
    		driverClass = prop.getProperty("jdbc.driver");
    		url = prop.getProperty("jdbc.url");
    		user = prop.getProperty("jdbc.user");
    		pwd = prop.getProperty("jdbc.pwd");
    	} catch (IOException e) {
    		e.printStackTrace();
    	}
    	
    	//加载驱动
    	try {
    		Class.forName(driverClass);
    	} catch (ClassNotFoundException e) {
    		e.printStackTrace();
    	}
    }
    
    
    public static Connection getConnection() {
    	Connection conn = null;
    	try {
    		conn = DriverManager.getConnection(url,user,pwd);
    	} catch (SQLException e) {
    		e.printStackTrace();
    	}
    	return conn;
    }

service方法  
package login;

import java.io.IOException;  
import java.sql.SQLException;

import javax.servlet.ServletContext;  
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 org.apache.commons.dbutils.QueryRunner;  
import org.apache.commons.dbutils.handlers.BeanHandler;

import domain.User;  
import utils.JdbcUtils;

/\*\*

*  Servlet implementation class LoginServlet  
    \*/  
    @WebServlet("/login")  
    public class LoginServlet extends HttpServlet \{  
    private static final long serialVersionUID = 1L;  
    @Override  
    public void init() throws ServletException \{  
    int count = 0;  
    this.getServletContext().setAttribute(“count”, count);  
    \}
    
    /\*\*
    
     *  @see HttpServlet\#doGet(HttpServletRequest request, HttpServletResponse response)  
        \*/  
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException \{  
        //1.获得用户名和密码  
        String uname = request.getParameter(“uname”);  
        String pwd = request.getParameter(“pwd”);
        
        //2.验证数据库总用户名和密码是否正确  
        QueryRunner runner = new QueryRunner();
        
        User user =null;  
        try \{  
        // runner=new QueryRunner JdbcUtils.getConnection();  
        user = runner.query(JdbcUtils.getConnection(),  
        “select \* from user where uname=? and pwd=?”, new BeanHandler<>(User.class),uname,pwd);  
        \} catch (SQLException e) \{  
        // TODO 自动生成的 catch 块  
        e.printStackTrace();  
        \}  
        //根据返回的结果，判断  
        if(user!=null) \{  
        //从servletcontext中取出count进行++运算  
        ServletContext countext = this.getServletContext();  
        Integer count =(Integer)countext .getAttribute(“count”);  
        count++;  
        //用户登录成功  
        response.getWriter().write(user.toString()+count);  
        countext.setAttribute(“count”, count);  
        \}else \{  
        //用户登录失败  
        response.getWriter().write(“sorry”);  
        \}  
        \}
    
    /\*\*
    
     *  @see HttpServlet\#doPost(HttpServletRequest request, HttpServletResponse response)  
        \*/  
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException \{  
        // TODO Auto-generated method stub  
        doGet(request, response);  
        \}

\}  
jsp页面  
<%@ page language=“java” contentType=“text/html; charset=UTF-8”  
pageEncoding=“UTF-8”%>

1.登陆界面

# 用户登录 #

用户名：  
密码: