JAVA Web显示登录页面全过程

╰半橙微兮° 2021-12-13 21:29 288阅读 0赞

**1. 创建JAVAWeb项目**  
略

**2. 导入jar包**  
![在这里插入图片描述][20190707125240922.png]  
导入到WebContent\\WEB-INF\\lib中。  
该文件夹下的jar包会自自动添加到工作空间中。  
3. 编写起始页服务器程序  
![在这里插入图片描述][20190707125515648.png]

package com.wf.servlet;
    
    import java.io.IOException;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    /** * 登录页面 * @ClassName PageServlet * @Description * @Author Wangfei * @Date 2019年7月7日 上午10:00:30 */
    public class PageServlet extends HttpServlet { 
    	
    	@Override
    	protected void service(HttpServletRequest req, HttpServletResponse resp) 
    			throws ServletException, IOException { 
    		//设置响应编码格式
    		resp.setContentType("text/html;charset=utf-8");
    		//获取请求信息
    		//处理请求
    		//响应处理结果
    		resp.getWriter().write("<html>");
    		resp.getWriter().write("<head>");
    		resp.getWriter().write("</head>");
    		resp.getWriter().write("<body>");
    		resp.getWriter().write("<form action='login' method='get'>");
    		resp.getWriter().write("用户名:<input type='text' name='uname' value=''/><br/>");
    		resp.getWriter().write("密码:<input type='password' name='pwd' value=''/><br/>");
    		resp.getWriter().write("<input type='submit' value='登录'/><br/>");
    		resp.getWriter().write("</form>");
    		resp.getWriter().write("</body>");
    		resp.getWriter().write("</html>");
    	}
    
    
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70]  
4. 编写MVC思想程序  
![在这里插入图片描述][20190707125640930.png]  
包dao存放数据库操作类

package com.wf.dao.impl;
    
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    
    import com.wf.dao.LoginDao;
    import com.wf.pojo.User;
    
    public class LoginDaoImpl implements LoginDao{ 
    
    	@Override
    	public User checkLoginDao(String uname, String pwd) { 
    		//声明Jdbc对象
    		Connection connection = null;
    		PreparedStatement preparedStatement = null;
    		ResultSet resultSet = null;
    		//声明数据存储对象
    		User user = null;
    		try { 
    			//加载驱动
    			Class.forName("com.mysql.jdbc.Driver");
    			//获取链接对象
    			connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/407","root","");
    			//创建Sql命令
    			String sql = "select * from t_user where uname=? and pwd=?";
    			//创建Sql命令对象
    			preparedStatement = connection.prepareStatement(sql);
    			//给占位符赋值
    			preparedStatement.setString(1, uname);
    			preparedStatement.setString(2, pwd);
    			//执行
    			resultSet = preparedStatement.executeQuery();
    			//遍历执行结果
    			while (resultSet.next()) { 
    				user = new User();
    				user.setUid(resultSet.getInt("uid"));
    				user.setUname(resultSet.getString("uname"));
    				user.setPwd(resultSet.getString("pwd"));
    			}
    			
    			
    		} catch (ClassNotFoundException e) { 
    			e.printStackTrace();
    		} catch (SQLException e) { 
    			e.printStackTrace();
    		}finally { 
    			//关闭资源
    			try { 
    				resultSet.close();
    			} catch (SQLException e) { 
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    			try { 
    				preparedStatement.close();
    			} catch (SQLException e) { 
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    			try { 
    				connection.close();
    			} catch (SQLException e) { 
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    		}
    		//返回
    		return user;
    	}
    
    }

包pojo存放对象实体类

package com.wf.pojo;
    /** * 用户实体类 * @ClassName User * @Description * @Author Wangfei * @Date 2019年7月7日 上午10:12:37 */
    
    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 + "]";
    	}
    	@Override
    	public int hashCode() { 
    		final int prime = 31;
    		int result = 1;
    		result = prime * result + ((pwd == null) ? 0 : pwd.hashCode());
    		result = prime * result + uid;
    		result = prime * result + ((uname == null) ? 0 : uname.hashCode());
    		return result;
    	}
    	@Override
    	public boolean equals(Object obj) { 
    		if (this == obj)
    			return true;
    		if (obj == null)
    			return false;
    		if (getClass() != obj.getClass())
    			return false;
    		User other = (User) obj;
    		if (pwd == null) { 
    			if (other.pwd != null)
    				return false;
    		} else if (!pwd.equals(other.pwd))
    			return false;
    		if (uid != other.uid)
    			return false;
    		if (uname == null) { 
    			if (other.uname != null)
    				return false;
    		} else if (!uname.equals(other.uname))
    			return false;
    		return true;
    	}
    	
    
    }

包servuce存放服务程序类

package com.wf.service.impl;
    
    import com.wf.dao.LoginDao;
    import com.wf.dao.impl.LoginDaoImpl;
    import com.wf.pojo.User;
    import com.wf.service.LoginService;
    
    public class LoginServiceImpl implements LoginService{ 
    
    	//创建Dao层对象
    	LoginDao ld = new LoginDaoImpl();
    	@Override
    	public User checkLoginService(String uname, String pwd) { 
    		
    		return ld.checkLoginDao(uname, pwd);
    	}
    
    }

servlet是服务器服务程序包

![在这里插入图片描述][20190707130121462.png]  
LoginServlet是登录服务程序

package com.wf.servlet;
    
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import com.wf.pojo.User;
    import com.wf.service.LoginService;
    import com.wf.service.impl.LoginServiceImpl;
    
    /** * 登录请求 * @ClassName LoginServlet * @Description * @Author Wangfei * @Date 2019年7月7日 上午10:00:44 */
    public class LoginServlet extends HttpServlet { 
    	@Override
    	protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 
    		//设置响应编码格式
    		resp.setContentType("text/html;charset=utf-8");
    		//获取请求信息
    		String uname = req.getParameter("uname");
    		String pwd = req.getParameter("pwd");
    		System.out.println(uname+":"+pwd);
    		//处理请求信息
    			//获取业务层对象
    			LoginService loginService = new LoginServiceImpl();
    			User user = loginService.checkLoginService(uname, pwd);
    			System.out.println(user);
    		//响应处理结果
    			if (user != null) { 
    				resp.getWriter().write("登录成功");
    			}else { 
    				resp.getWriter().write("登录失败");
    			}
    	}
    
    }

PagServlet是登录主页服务程序

**5. 建立数据库**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70 1]  
**6. 启动服务器，浏览器输入网址**  
![在这里插入图片描述][20190707130811587.png]  
![在这里插入图片描述][20190707130824833.png]  
[http://localhost:8080/Login/page][http_localhost_8080_Login_page]

1.  运行结果  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70 2]  
    输入数据库中的用户名和密码  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70 3]  
    控制台输出  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70 4]

[20190707125240922.png]: /images/20211213/8e18d8ad271143b5ab13d566976df24a.png
[20190707125515648.png]: /images/20211213/bf92596f795f4cf7b2b0848d6f9a95cb.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70]: /images/20211213/62c6bae6534c40368eae549facd406ea.png
[20190707125640930.png]: /images/20211213/e058821397344dcabc7f97447139914e.png
[20190707130121462.png]: /images/20211213/4e0e27af3d3742f8a52e057f07b58178.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70 1]: /images/20211213/bd67188b4ee64fa88ea704e4de1ba623.png
[20190707130811587.png]: /images/20211213/84f2d7db3027421482c52477c4fff4f3.png
[20190707130824833.png]: /images/20211213/074fbd985c034b9a9d8b007fbf2ef606.png
[http_localhost_8080_Login_page]: http://localhost:8080/Login/page
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70 2]: /images/20211213/eb2908227549469dadf6b6363044ce58.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70 3]: /images/20211213/40e209374bcc4ee08e4637eb293a1818.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE1NTg2Ng_size_16_color_FFFFFF_t_70 4]: /images/20211213/2cbbb1f3a9a14c2bbb2230729156803e.png