servlet连接数据库，实现删除功能

淡淡的烟草味﹌ 2023-06-20 10:46 24阅读 0赞

## servlet连接数据库，实现删除功能 ##

配置数据库

jdbc.driver=com.mysql.jdbc.Driver
    jdbc.url=jdbc:mysql:///test
    jdbc.user=root
    jdbc.pwd=123456

创建实体类

/**
     * 
     */
    package entity;
    
    /**
     * @author xiao
     *
     */
    public class User {
        
    	private String uname;
    	private int uid;
    	public String getUname() {
        
    		return uname;
    	}
    	public void setUname(String uname) {
        
    		this.uname = uname;
    	}
    	public int getUid() {
        
    		return uid;
    	}
    	public void setUid(int uid) {
        
    		this.uid = uid;
    	}
    	@Override
    	public String toString() {
        
    		return "User [uname=" + uname + ", uid=" + uid + "]";
    	}
    	
    
    }

连接数据库

package utils;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    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;
    	}
    	   public static void release(Connection conn, PreparedStatement ps, ResultSet rs) {
        
    	        try {
        
    	            if(rs != null) {
        
    	                rs.close();
    	            }
    	            if(ps != null) {
        
    	                ps.close();
    	            }
    	            if(conn != null) {
        
    	                conn.close();
    	            }
    	        } catch (Exception e) {
        
    	            e.printStackTrace();
    	        }
    	    }
    }

service方法区，这里注意，删除的时候，可以根据id或者name ，只要是唯一即可

package dao;
    
    import java.io.IOException;
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    
    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 utils.JdbcUtils;
    
    /**
     * Servlet implementation class DelDao
     */
    @WebServlet("/DelDao")
    public class DelDao extends HttpServlet {
        
    
    	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        
    		//String uname = request.getParameter("uname");
    	   String uid = request.getParameter("uid");
    	//	String pwd = request.getParameter("pwd");
    		String op=request.getParameter("op");
    		if ("delete".equals(op)) {
        
    			regist(request,response);
    		}
    	}		
    		 public void regist(HttpServletRequest request, HttpServletResponse response) {
        
    		           
    	                   String uid = request.getParameter("uid");
    	                   System.out.println(uid);
    	                   //操作数据库
    	                   Connection conn=null;
    	                   PreparedStatement ps=null;
    	                   int s=0;
    	                   try {
        
    						conn=JdbcUtils.getConnection();
    						String sql="delete from user where  uid=?";
    						ps=conn.prepareStatement(sql);
    						
    						ps.setString(1, uid);
    						s=ps.executeUpdate();
    					} catch (Exception e) {
        
    						e.printStackTrace();		
    					}finally {
        
    						JdbcUtils.release(conn, ps, null);
    					}
    	    			if(s>0) {
        
    	    				System.out.println("删除成功");
    	    			}
    	}
    	
    	/**
    	 * @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"%>
    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>删除页面</title>
    </head>
    <body>
    <h1>删除操作</h1>
    <form action="DelDao"  method="post">
    <input type="hidden" name="op" value="delete"> 
    id:<input type="text"  name="uid"><br/>
    <input type="submit"  value="确认删除"><br/>
    
    </form>
    
    </body>
    </html>