package text1; import java.sql.*; public class JDBCutils { //获取连接对象的方法 public static Connection getcon() throws Exception { Connection con=null; Class.forName("com.mysql.jdbc.Driver"); con= DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbc", "root", "root"); return con; } //关闭连接 释放资源 public static void realse(ResultSet rs,Statement stmt,Connection con) { if (rs != null) { try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } if (stmt != null) { try { stmt.close(); } catch (SQLException e) { e.printStackTrace(); } if (con != null) { try { con.close(); } catch (SQLException e) { e.printStackTrace(); } } } } } }
package text1; import java.util.Date; public class user { private int id; private String username; private String password; private String email; private String birthday; 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; } public String getBirthday() { return birthday; } public void setBirthday(String birthday) { this.birthday = birthday; } }
package text1; import org.apache.tomcat.jni.User; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import java.util.List; import java.sql.Connection; import java.sql.Statement; //完成对数据库的增删改查操作 public class usersdao { //提供一个添加方法 public boolean insert(user user){ Connection con=null; Statement stmt=null; try{ //获取连接对象 con=JDBCutils.getcon(); //获取执行sql语句的对象 stmt=con.createStatement(); String sql="insert into yonghu "+"values('" +user.getId()+"','" +user.getUsername()+"','" +user.getPassword()+"','" +user.getEmail()+"','" +user.getBirthday()+"'" +")"; int a =stmt.executeUpdate(sql); if(a==1){ return true; } }catch (Exception e){ /* throw new RuntimeException(e);*/ e.printStackTrace(); }finally { JDBCutils.realse(null,stmt,con); } return false; } //提供查询所有的方法 public List<user> findalluser(){ Connection con=null; ResultSet rs=null; Statement stmt=null; try { con=JDBCutils.getcon(); stmt=con.createStatement(); String sql="select * from yonghu"; rs=stmt.executeQuery(sql); /* while (rs.next()){ int num=rs.getInt("id"); String username=rs.getString("username"); }*/ List<user> list=new ArrayList<user>(); while (rs.next()){ user user=new user(); user.setId(rs.getInt("id")); user.setUsername(rs.getString("username")); user.setPassword(rs.getString("password")); user.setEmail(rs.getString("email")); user.setBirthday(rs.getString("birthday")); list.add(user); } return list; }catch (Exception e){ e.printStackTrace(); }finally { JDBCutils.realse(rs,stmt,con); } return null; } //根据id来查询记录 public user finduserbyid(int id){ Connection con=null; PreparedStatement stme=null; ResultSet rs=null; try{ con=JDBCutils.getcon(); String sql="select * from yonghu where id=?"; stme=con.prepareStatement(sql); //给占位符赋值 stme.setInt(1,id); rs=stme.executeQuery(); while (rs.next()){ user user=new user(); user.setId(rs.getInt("id")); user.setUsername(rs.getString("username")); user.setPassword(rs.getString("password")); user.setEmail(rs.getString("email")); user.setBirthday(rs.getString("birthday")); return user; } }catch (Exception e){ e.printStackTrace(); }finally { JDBCutils.realse(rs,stme,con); } return null; } //提供根基id修改数据方法 public boolean update(user user){ Connection con=null; PreparedStatement stmt=null; try { con=JDBCutils.getcon(); String sql="update yonghu set username=?,password=? where id =?"; stmt=con.prepareStatement(sql); stmt.setString(1,user.getUsername()); stmt.setString(2,user.getPassword()); stmt.setInt(3,user.getId()); int row=stmt.executeUpdate(); if(row==1){ return true; } }catch (Exception e){ e.printStackTrace(); }finally { JDBCutils.realse(null,stmt,con); } return false; } //提供删除方法 public boolean delete(int id){ Connection con=null; PreparedStatement stmt=null; try{ con=JDBCutils.getcon(); String sql="delete from yonghu where id=?"; stmt=con.prepareStatement(sql); stmt.setInt(1,id); if(stmt.executeUpdate()==1){ return true; } }catch (Exception e){ e.printStackTrace(); }finally { JDBCutils.realse(null,stmt,con); } return false; } }
package text1; import java.util.List; public class jdbcinserttext { public static void main(String[] args) { usersdao dao=new usersdao(); user user=new user(); user.setId(2); user.setUsername("guoyang"); user.setPassword("4560"); user.setEmail("[email protected]"); user.setBirthday("2020-4-20"); dao.insert(user);
package text1; public class deleteusertest { public static void main(String[] args) { usersdao dao=new usersdao(); user u=new user(); boolean f=dao.delete(1); System.out.println(f); } }
package text1; public class updateusertest { public static void main(String[] args) { usersdao dao=new usersdao(); user u=new user(); u.setId(18); u.setUsername("guoyang"); u.setPassword("777777"); boolean f=dao.update(u); System.out.println(f); } }
package text1; import java.util.List; public class findallusertest { public static void main(String[] args) { usersdao dao=new usersdao(); user u=dao.finduserbyid(18); System.out.println(u.getUsername()); } }
package text1; public class finduserbyidtest { public static void main(String[] args) { usersdao dao=new usersdao(); user u=dao.finduserbyid(18); System.out.println(u.getUsername()); } }