Jsp第六次作业JDBC

UsersDao

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

/*
 完成对数据库的增删改查（crud操作）
 */
public class UsersDao {
    
    
    
    // 1.提供添加方法
    public boolean insert(User user) {
        Connection con = null;
        Statement stmt = null;
        try {
//1.获取连接对象
            con=JDBCUtils.getCon();
//2.获取执行sql语句的对象
            stmt=con.createStatement();
//3.执行sql语句(添加信息语句)
            java.util.Date birthday=user.getBirthDay();
            String sqlBirthDay=String.format("%tF",birthday);//把日期类型转换成字符串类型
            String sql="insert into users(id,name,password,email,birthday)"+"values("
                    +user.getId()+",'"
                    +user.getUsername()+"','"
                    +user.getPassword()+"','"
                    +user.getEmail()+"','"
                    +sqlBirthDay+"'"//user.getBirthDay()替换成sqlBirthDay
                    +")";
            int row = stmt.executeUpdate(sql);
            if(row>0){
                //插入成功
                return true;
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            JDBCUtils.realse(null, stmt, con);
        }

        return false;
    }
    
    
    
    //2.提供查询所有的方法
    public List<User>findAllUser(){
        Connection con= null;
        Statement stmt = null;
        ResultSet rs = null;
        try{
            //1.获取连接对象
            con = JDBCUtils.getCon();
            //2.获取执行sql语句的对象
            stmt = con.createStatement();
            //3.执行sql语句(查询语句)
            String sql ="select * from users";
            rs = stmt.executeQuery(sql);
            //4.遍历rs
            List<User> list = new ArrayList<User>();
            while(rs.next()){
                //一行数据对应一个对象，获取每一行的对象，就设置给一个user对象
                User user = new User();
                user.setId(rs.getInt("id"));
                user.setUsername(rs.getString("name"));
                user.setPassword(rs.getString("password"));
                user.setEmail(rs.getString("email"));
                java.sql.Date birthday = rs.getDate("birthday");
                user.setBirthDay(birthday);//子类把值传递给父类
                //把对象添加到集合中
                list.add(user);                
            }
            return list;
                
        }catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            JDBCUtils.realse(rs, stmt, con);
        }        
    //    return null;
    }
    
    
    
    //3.根据id，来查询记录
    public User findUserById(int id){
        Connection con= null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try{
            //1.获取连接对象
            con = JDBCUtils.getCon();
            //2.获取执行sql语句的对象
            String sql ="select * from users where id=?";
            stmt = con.prepareStatement(sql);
            //3.执行sql语句,给id赋值
            stmt.setInt(1, id);
        
            rs = stmt.executeQuery();
            //4.遍历rs
            
            if(rs.next()){
                //一行数据对应一个对象，获取每一行的对象，就设置给一个user对象
                User user = new User();
                user.setId(rs.getInt("id"));
                user.setUsername(rs.getString("name"));
                user.setPassword(rs.getString("password"));
                user.setEmail(rs.getString("email"));
                java.sql.Date birthday = rs.getDate("birthday");
                user.setBirthDay(birthday);//子类把值传递给父类
                return user;            
            }
            
        }catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            JDBCUtils.realse(rs, stmt, con);
        }        
        return null;            
    }
    

    
    //4.提供一个修改方法，根据id值修改记录
    public boolean update(User user){
    Connection con = null;
    PreparedStatement stmt = null;
    try {
//1.获取连接对象
        con=JDBCUtils.getCon();
//2.获取执行sql语句的对象
        String sql="update users set name =?,password=? where id=?";
        stmt = con.prepareStatement(sql);//2.的sql语句*
//3.执行sql语句(给占位符赋值)
        
        stmt.setString(1, user.getUsername());
        stmt.setString(2, user.getPassword());
        stmt.setInt(3, user.getId());
                
        int row = stmt.executeUpdate();//应该（）里无sql,因为在2.里已经传了sql语句*
        if(row>0){
            //插入成功
            return true;
        }
    } catch (Exception e) {
        throw new RuntimeException(e);
    } finally {
        JDBCUtils.realse(null, stmt, con);
    }
    return false;
    }
    
    
    //5.删除方法
    public boolean delete (int id){
        Connection con = null;
        PreparedStatement stmt = null;
        try {
    //1.获取连接对象
            con=JDBCUtils.getCon();
    //2.获取执行sql语句的对象
            String sql="delete from users where id=?";
            stmt = con.prepareStatement(sql);//2.的sql语句*
    //3.执行sql语句(给占位符赋值)
            
            stmt.setInt(1,id);
                    
            int row = stmt.executeUpdate();//应该（）里无sql,因为在2.里已经传了sql语句*
            if(row>0){
                //插入成功
                return true;
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            JDBCUtils.realse(null, stmt, con);
        }
        return false;
        
    }
}

JDBCUtils

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


public class JDBCUtils {
//获取连接对象的方法
    public static Connection getCon() throws Exception{
        //1.加载数据库驱动
                Class.forName("com.mysql.jdbc.Driver");
                //2.通过DriverManager获取数据库连接
                Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbc", "root", "root");
                return con;
                //3.通过Connection対象获取Statement対象                
    }
    
//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){
                //TODO Auto-generated catch block
                e.printStackTrace();
                }
            rs=null;
            }
        if(stmt!=null){
            try{
                stmt.close();
            }catch (SQLException e){
                //TODO Auto-generated catch block
                e.printStackTrace();
                }
            stmt=null;
            }
        if(con!=null){
            try{
                con.close();
            }catch (SQLException e){
                e.printStackTrace();
                }
            con=null;
            }
    }
}

User

import java.util.Date;

public class User {
private int id;
private String username;
private String password;
private String email;
private Date 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 Date getBirthDay() {
    return birthDay;
}
public void setBirthDay(Date birthDay) {
    this.birthDay = birthDay;
}

}

JdbcInsertTest

import java.util.Date;

public class JdbcInsertTest {
public static void main(String[] args){
    //测试1插入信息代码
    UsersDao dao= new UsersDao();
    User user= new User();
    user.setId(6);
    user.setUsername("gjm");
    user.setPassword("789");
    user.setEmail("gjm@qq.com");
    user.setBirthDay(new Date(1998-07-17));
    boolean flag=dao.insert(user);
    System.out.print(flag);

}
}

FindAllUserTest

import java.util.List;

public class FindAllUserTest {
    public static void main(String[] args){
        //测试2查询所有信息条数代码
        UsersDao dao= new UsersDao();
        List<User> list =dao.findAllUser();    
        System.out.println(list.size());
}
}

FindUserByIdTest

public class FindUserByIdTest {
    public static void main(String[] args){
        //测试3查询id=？的名字代码
        UsersDao dao= new UsersDao();
    User u = dao.findUserById(5);
    System.out.println(u.getUsername());
    }
}

UpdateUserTest

public class UpdateUserTest {
    public static void main(String[] args){
        //测试4修改信息代码
        UsersDao dao= new UsersDao();
        User u = new User();
        u.setId(4);
        u.setUsername("GJM");
        u.setPassword("987");
        boolean flag = dao.update(u);
        System.out.println(flag);
        //true则成功，否则不成功
}
}

DeleteUserTest

public class DeleteUserTest {
    public static void main(String[] args){
        //测试5删除信息代码
        UsersDao dao= new UsersDao();
        boolean flag = dao.delete(6);
        System.out.println(flag);
    }
}

 最终表

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原文地址：https://www.cnblogs.com/gjm717/p/12728820.html