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; } }