【javaweb：servlet】网站登录信息校验，并返回页面提示

素颜马尾好姑娘i 2022-06-01 09:30 253阅读 0赞

package indi.login;
    
    import java.io.IOException;
    import java.sql.SQLException;
    
    import javax.servlet.ServletException;
    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 indi.domain.User;
    import indi.utils.DataSourceUtils;
    
    public class LoginServlet extends HttpServlet {
    
    	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		//1.设置request的解码字符集为UTF-8
    		request.setCharacterEncoding("UTF-8");
    		//2.获取用户的登录信息
    		String username=request.getParameter("username");
    		String password=request.getParameter("password");
    		
    		//3.调用业务方法去查询用户,针对不同的查询结果进行处理
    		User selectResult=null;
    		try {
    			selectResult = select(username,password);
    		} catch (SQLException e) {
    			e.printStackTrace();
    		}
    		if(selectResult!=null) {
    			//表示登录成功
    			//则将用户跳转至网站首页,采用"重定向"的方法(redirect)
    			response.sendRedirect(request.getContextPath()+"/index.jsp");
    		}else {
    			//表示登录失败
    			//则将用户界面重新跳转至login.jsp，采用"请求转发"(dispatch)的方法
    			//下面代码运用request域对象的特性，在一次转发中传递信息
    			request.setAttribute("loginInfo", "用户名或密码错误！");
    			request.getRequestDispatcher("/login.jsp").forward(request, response);
    		}
    	}
    	//根据登录信息，去数据库中查询,并返回User对象
    	public User select(String username,String password) throws SQLException {
    		QueryRunner qr=new QueryRunner(DataSourceUtils.getDataSource());
    		String sql="select * from user where username=? and password=?";
    		User user = qr.query(sql, new BeanHandler<>(User.class), username,password);
    		return user;
    	}
    
    	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		doGet(request, response);
    	}
    }