• 安卓第六次作业


    package dao;
    
    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;
    
    import javabean.User;
    import utils.JDBCUtils;
    
    public class UsersDao {
        //增加数据
        public boolean insert(User user){
            Connection con=null;
            Statement state=null;
            try {
                con=JDBCUtils.getCon();
                state=con.createStatement();
                java.util.Date birthday=user.getBirthDay();
                String sqlBirthday=String.format("%tF", birthday);
                String sql="insert into user(id,username,password,email,birthday) "
                        + "values('"+user.getId()+"','"
                        +user.getUsername()+"','"
                        +user.getPassword()+"','"
                        +user.getEmail()+"','"
                        +sqlBirthday+"')";
                int row=state.executeUpdate(sql);
                if(row>0){
                    return true;
                }
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                JDBCUtils.realse(null,state,con);
            }
            return false;
        }
        
        
        
        //查询全部数据
        public List<User> findAllUser(){
            Connection con=null;
            Statement state=null;
            ResultSet rs=null;
            try {
                con=JDBCUtils.getCon();
                state=con.createStatement();
                String sql="select * from user";
                rs=state.executeQuery(sql);
                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"));
                    java.sql.Date birthDay=rs.getDate("birthday");
                    user.setBirthDay(birthDay);
                    list.add(user);
                }
                return list;
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                JDBCUtils.realse(rs,state,con);
            }
            return null;
        }
        
        
        
        //根据ID查询记录
        public User findById(int id){
            Connection con=null;
            PreparedStatement prs=null;
            ResultSet rs=null;
            try {
                con=JDBCUtils.getCon();
                String sql="select * from user where id=?";
                prs=con.prepareStatement(sql);
                prs.setInt(1, id);
                rs=prs.executeQuery();
                if(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"));
                    java.sql.Date birthDay=rs.getDate("birthday");
                    user.setBirthDay(birthDay);
                    return user;
                }
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                JDBCUtils.realse(rs,prs,con);
            }
            return null;
        }
        
        
        //根据ID修改
        public boolean update(User user){
            Connection con=null;
            PreparedStatement prs=null;
            try {
                con=JDBCUtils.getCon();
                String sql="update user set username=?,password=? where id=?";
                prs=con.prepareStatement(sql);
                prs.setString(1, user.getUsername());
                prs.setString(2, user.getPassword());
                prs.setInt(3, user.getId());
                int row=prs.executeUpdate();
                if(row>0){
                    return true;
                }
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                JDBCUtils.realse(null,prs,con);
            }
            return false;
            
        }
        
        
        //删除根据Id
        public boolean deleteById(int id){
            Connection con=null;
            PreparedStatement prs=null;
            try {
                con=JDBCUtils.getCon();
                String sql="delete from user where id=?";
                prs=con.prepareStatement(sql);
                prs.setInt(1, id);
                int row=prs.executeUpdate();
                if(row>0){
                    return true;
                }
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                JDBCUtils.realse(null,prs,con);
            }
            return false;
            
        }
        
    
    }
    复制代码
    复制代码
    package javabean;
    
    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;
        }
    }
    复制代码
    复制代码
    package utils;
    
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    
    public class JDBCUtils {
        public static Connection getCon(){
            try {
                Class.forName("com.mysql.jdbc.Driver");
                Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbc","root","root");
                return con;
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return null;
        }
        //关闭连接
        public static void realse(ResultSet rs,Statement state,Connection con){
            try {
                if(rs !=null){
                    rs.close();
                }
                if(state !=null){
                    state.close();
                }
                if(con !=null){
                    con.close();
                }
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        }
    
    }
    复制代码
    复制代码
    package Test;
    
    import java.util.Date;
    
    import dao.UsersDao;
    import javabean.User;
    
    public class InsTest {
    
        public static void main(String[] args) {
            UsersDao dao=new UsersDao();
            User user=new User();
            user.setId(1);
            user.setUsername("zhaoqian");
            user.setPassword("123456");
            user.setEmail("1558938514@qq.com");
            user.setBirthDay(new Date());
            System.out.println(dao.insert(user));
        }
    
    }
    复制代码
    复制代码
    package Test;
    
    import java.util.ArrayList;
    import java.util.List;
    
    import dao.UsersDao;
    import javabean.User;
    
    public class ShowTest {
    
        public static void main(String[] args) {
            UsersDao dao=new UsersDao();
            List<User> list=dao.findAllUser();
            for(int i=0;i<list.size();i++){
                System.out.println(list.get(i));
            }
    
        }
    
    }
    复制代码
    复制代码
    package Test;
    
    import dao.UsersDao;
    import javabean.User;
    
    public class ShowOneTest {
    
        public static void main(String[] args) {
            UsersDao dao=new UsersDao();
            User u=dao.findById(1);
            System.out.println(u.getUsername());
        }
    
    }
    复制代码
    复制代码
    package Test;
    
    import dao.UsersDao;
    import javabean.User;
    
    public class UpdateTest {
    
        public static void main(String[] args) {
            UsersDao dao=new UsersDao();
            User user=new User();
            user.setId(1);
            user.setUsername("zhangsan");
            user.setPassword("zhangsan123");
            System.out.println(dao.update(user));
        }
    
    }
    复制代码
    复制代码
    package Test;
    
    import dao.UsersDao;
    
    public class DelectTest {
    
        public static void main(String[] args) {
            UsersDao dao=new UsersDao();
            System.out.println(dao.deleteById(1));
        }
    
    }
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  • 原文地址:https://www.cnblogs.com/fff1479/p/14027228.html
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