jsp第六次作业

 jdbcdelete类

package jdbc;

public class jdbcdelete {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Userding dao=new Userding();
        boolean dhy =dao.delete(2);
        System.out.println(dhy);
        

    }

}

Userding类
package jdbc;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
     public class Userding {

    /*
     * 对数据库进行增删改查
     * 
     */

        //1.提供添加方法
        public boolean insert(User user){
            Connection con= null;
            Statement  st = null;
            try{
                //1.获取连接对象
                con=JDBCUtils.getCon();
                //2.获取执行sql语句的对象
                st=con.createStatement();
                //3.执行sql


                String sql="insert into users(id,name,password,email)"+"values('"+user.getId()+"','"
                        +user.getUsername()+"','"
                        +user.getPassword()+"','"
                        +user.getEmail()+"','"
                        
                        +")";
                int row=st.executeUpdate(sql);
                if(row>0){
                    //插入成功
                    return true;
                }
                
            }catch(Exception e){
                throw new RuntimeException(e);
            }finally{
                JDBCUtils.resulse(null, st, con);
            }
            
            return false;
        }
        
        //2.提供查询所有方法
        public List<User>findAllUser(){
            Connection con = null;
            Statement st = null;
            ResultSet rs = null;
            try{
                //1.获取连接对象
                con = JDBCUtils.getCon();
                //2.获取执行SQL语句对象
                st = con.createStatement();
                //3.执行SQL
                String sql = "select * from ddd";
                rs = st.executeQuery(sql);
                //4.遍历rs
                List<User>list = new ArrayList<User>();
                while(rs.next()){
                    User user = new User();
                    user.setId(rs.getInt("id"));
                    user.setUsername(rs.getString("name"));
                    user.setPassword(rs.getString("password"));
                    user.setEmail(rs.getString("email"));
                
                    //把对象添加到集合中
                    list.add(user);
                }
                return list;
            }catch(Exception e){
                throw new RuntimeException(e);
            }finally{
                JDBCUtils.resulse(rs, st, con);
            }    
        }
        //3.提供根据id查询方法
        public User findUserById(int id){
            Connection con = null;
            ResultSet rs= null;
            PreparedStatement st = null;
            try{
                //1.获取连接
                con = JDBCUtils.getCon();
                //2.获取执行sql语句对象
                String sql = "select * from ddd where id =?";
                st = con.prepareStatement(sql);
                //3.执行aql
                st.setInt(1, id);
                rs = st.executeQuery();
                //4.遍历rs
                if(rs.next()){
                    User user = new User();
                    user.setId(rs.getInt("id"));
                    user.setUsername(rs.getString("name"));
                    user.setPassword(rs.getString("password"));
                    user.setEmail(rs.getString("email"));

                    return user;
                }
            }catch(Exception e){
                throw new RuntimeException(e);
            }finally{
                JDBCUtils.resulse(rs, st, con);
            }
            return null;
        }
        //4.提供修改方法
        public boolean update(User user){
            Connection con = null;
            PreparedStatement st = null;
            ResultSet rs = null;
            try{
                //1.获取连接
                con = JDBCUtils.getCon();
                //2.执行SQL语句对象
                String sql = "update from ddd name=?,password=? where id=? " ;
                st = con.prepareStatement(sql);
                //3.执行SQL，给占位符赋值
                st.setString(1, user.getUsername());
                st.setString(2, user.getPassword());
                st.setInt(3, user.getId());
                int row = st.executeUpdate();
                if(row>0){
                    //修改成功
                    return true;
                }
            }catch(Exception e){
                throw new RuntimeException(e);
            }finally{
                JDBCUtils.resulse(rs, st, con);
            }
            return false;
        }
        //5.提供删除方法
        public boolean delete(int id){
            Connection con = null;
            PreparedStatement st =null;
            ResultSet rs = null;
            try{
                //1.获取连接
                con = JDBCUtils.getCon();
                //2.执行SQL语句对象
                String sql = "delete  from ddd where id=?";
                st = con.prepareStatement(sql);
                //3.执行SQL，给占位符赋值
                st.setInt(1, id);
                int row = st.executeUpdate();
                if(row>0){
                    //删除成功
                    return true;
                }
            }catch(Exception e){
                throw new RuntimeException(e);
            }finally{
                JDBCUtils.resulse(rs, st, con);
            }
            return false;
        }
    }

JDBCUtils类

package jdbc;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBCUtils {
    //获取连接对象的方法
    public static Connection getCon() throws Exception{
        Class.forName("com.mysql.jdbc.Driver");
        Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/dinghaiyang","root","root");
        return con;
        }
        
    
    
    public static void resulse(ResultSet rs,Statement st,Connection con) {
        if(rs!=null){
            try {
                rs.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            if(st!=null){
                try {
                    rs.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                
                }
            if(con!=null){
                try {
                    rs.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                }
            }
        }
}    

User类

package jdbc;

public class User {
    private int id;
    private String username;
    private String password;
    private String email;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    

}