浅学JDBC 笔记记录
- 一、
- 1. JDBC的概念
- 2. JDBC快速入门
- 2.1 DriverManager
- 2.2 Connection
- 2.3 Statement
- 2.4 ResultSet
- 3. JDBC入门案例使用
- 3.1 查询所有学生信息
- 3.2 根据id查询学生信息&&新增学生信息&&修改学生信息&&删除学生信息
一、
1. JDBC的概念
2. JDBC快速入门
import java.sql.*;
public class JDBCDemo01 {
public static void main(String[] args) throws ClassNotFoundException, SQLException {
//1. 导入jar包 此处使用maven依赖引入
//2. 注册驱动
// 此步骤可以跳过 源码中已经填充
// Class.forName("com.mysql.jdbc.Driver");
//3. 获取连接
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/db8", "root", "root");
//4. 获取执行者对象
Statement stat = con.createStatement();
//5. 执行sql语句，并且接受sql语句返回结果
String sql="select * from account";
ResultSet rs = stat.executeQuery(sql);
//6.处理结果
while (rs.next()){
System.out.println(rs.getInt("id")+"\t"+rs.getString("name")+"\t"+rs.getString("money"));
}
//7.释放相关资源
con.close();
stat.close();
rs.close();
}
}
上面使用的类进行详解
2.1 DriverManager
2.2 Connection
2.3 Statement
2.4 ResultSet
3. JDBC入门案例使用
数据准备
create database db1;
use db1;
#创建Student表
create table student(
id int primary key auto_increment,
name varchar(20),
age int,
birthday Date
);
#添加数据
insert into student values (null,'张三',23,'1999-09-23'),(null,'李四',24,'1998-08-10'),(null,'王五',25,'1996-06-06')
,(null,'赵六',26,'1994-10-20');
实体类
package domain;
import java.util.Date;
public class Student {
private Integer id;
private String name;
private Integer age;
private Date birthday;
public Student() {
}
public Student(Integer id, String name, Integer age, Date birthday) {
this.id = id;
this.name = name;
this.age = age;
this.birthday = birthday;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "domain.Student{" +
"id=" + id +
", name='" + name + '\'' +
", age=" + age +
", birthday=" + birthday +
'}';
}
}
3.1 查询所有学生信息
dao:
public interface StudentDao {
ArrayList<Student> findAll();
}
daoImpl:
public class StudentDaoImpl implements StudentDao{
//查询所有学生信息
@Override
public ArrayList<Student> findAll() {
ArrayList<Student> list=new ArrayList();
Connection con =null;
Statement statement =null;
ResultSet resultSet =null;
try {
//1.注册驱动
Class.forName("com.mysql.jdbc.Driver");
//2.获取连接
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/db1", "root", "root");
//3.获取执行者对象
statement = con.createStatement();
//4.执行sql语句。并且接受返回的结果集
String sql="select * from student";
resultSet = statement.executeQuery(sql);
//5.处理结果集
while (resultSet.next()){
Integer id=resultSet.getInt("id");
String name=resultSet.getString("name");
Integer age=resultSet.getInt("age");
Date date=resultSet.getDate("birthday");
//封装Student对象
Student student=new Student(id,name,age,date);
//将Student保存到集合对象
list.add(student);
}
} catch (Exception e) {
e.printStackTrace();
}finally {
if (con!=null){
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (statement!=null){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (resultSet!=null){
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
return list;
}
}
service:
public interface StudentService {
//查询所有学生信息
ArrayList<Student> findAll();
}
serviceImpl:
public class StudentServiceImpl implements StudentService{
private StudentDao dao=new StudentDaoImpl();
@Override
public ArrayList<Student> findAll() {
return dao.findAll();
}
}
controller:
package controller;
import domain.Student;
import org.junit.Test;
import service.StudentService;
import service.StudentServiceImpl;
import java.util.ArrayList;
public class StudentController {
private StudentService service=new StudentServiceImpl();
@Test
public void findAll(){
ArrayList<Student> list = service.findAll();
for (Student student:list){
System.out.println(student);
}
}
}
成功：
3.2 根据id查询学生信息&&新增学生信息&&修改学生信息&&删除学生信息
dao:
package dao;
import domain.Student;
import java.util.ArrayList;
/**
Dao层接口
*/
public interface StudentDao {
//查询所有学生信息
ArrayList<Student> findAll();
//条件查询，根据id获取学生信息
Student findById(Integer id);
//新增学生信息
int insert(Student stu);
//修改学生信息
int update(Student stu);
//删除学生信息
int delete(Integer id);
}
daoImpl:
package dao;
import domain.Student;
import java.sql.*;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
public class StudentDaoImpl implements StudentDao{
//查询所有学生信息
@Override
public ArrayList<Student> findAll() {
ArrayList<Student> list=new ArrayList();
Connection con =null;
Statement statement =null;
ResultSet resultSet =null;
try {
//1.注册驱动
Class.forName("com.mysql.jdbc.Driver");
//2.获取连接
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/db1?useSSL=false", "root", "root");
//3.获取执行者对象
statement = con.createStatement();
//4.执行sql语句。并且接受返回的结果集
String sql="select * from student";
resultSet = statement.executeQuery(sql);
//5.处理结果集
while (resultSet.next()){
Integer id=resultSet.getInt("id");
String name=resultSet.getString("name");
Integer age=resultSet.getInt("age");
Date date=resultSet.getDate("birthday");
//封装Student对象
Student student=new Student(id,name,age,date);
//将Student保存到集合对象
list.add(student);
}
} catch (Exception e) {
e.printStackTrace();
}finally {
if (con!=null){
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (statement!=null){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (resultSet!=null){
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
return list;
}
//条件查询，根据id获取学生信息
@Override
public Student findById(Integer id) {
Student student=new Student();
Connection con =null;
Statement statement =null;
ResultSet resultSet =null;
try {
//1.注册驱动
Class.forName("com.mysql.jdbc.Driver");
//2.获取连接
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/db1?useSSL=false", "root", "root");
//3.获取执行者对象
statement = con.createStatement();
//4.执行sql语句。并且接受返回的结果集
String sql="select * from student where id='"+id+"'";
resultSet = statement.executeQuery(sql);
//5.处理结果集
while (resultSet.next()){
Integer sid=resultSet.getInt("id");
String name=resultSet.getString("name");
Integer age=resultSet.getInt("age");
Date date=resultSet.getDate("birthday");
//封装Student对象
student=new Student(sid,name,age,date);
}
} catch (Exception e) {
e.printStackTrace();
}finally {
if (con!=null){
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (statement!=null){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (resultSet!=null){
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
return student;
}
//新增学生信息
@Override
public int insert(Student stu) {
Connection con =null;
Statement statement =null;
int result=0;
try {
//1.注册驱动
Class.forName("com.mysql.jdbc.Driver");
//2.获取连接
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/db1?useSSL=false", "root", "root");
//3.获取执行者对象
statement = con.createStatement();
//4.执行sql语句。并且接受返回的结果集
Date birthday = stu.getBirthday();
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
String date = sdf.format(birthday);
String sql="insert into student values('"+stu.getId()+ "','"+stu.getName()+"','"+stu.getAge()+"','"+date+"')";
result = statement.executeUpdate(sql);
//5.处理结果集
} catch (Exception e) {
e.printStackTrace();
}finally {
if (con!=null){
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (statement!=null){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
return result;
}
//修改学生信息
@Override
public int update(Student stu) {
Connection con =null;
Statement statement =null;
int result=0;
try {
//1.注册驱动
Class.forName("com.mysql.jdbc.Driver");
//2.获取连接
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/db1?useSSL=false", "root", "root");
//3.获取执行者对象
statement = con.createStatement();
//4.执行sql语句。并且接受返回的结果集
Date birthday = stu.getBirthday();
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
String date = sdf.format(birthday);
String sql="update student set id='"+stu.getId()+"',name='"+stu.getName()+"',age='"+stu.getAge()+"',birthday='"+date+"' where id='"+stu.getId()+"'";
result = statement.executeUpdate(sql);
//5.处理结果集
} catch (Exception e) {
e.printStackTrace();
}finally {
if (con!=null){
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (statement!=null){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
return result;
}
//删除学生信息
@Override
public int delete(Integer id) {
Connection con =null;
Statement statement =null;
int result=0;
try {
//1.注册驱动
Class.forName("com.mysql.jdbc.Driver");
//2.获取连接
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/db1?useSSL=false", "root", "root");
//3.获取执行者对象
statement = con.createStatement();
//4.执行sql语句。并且接受返回的结果集
String sql="delete from student where id='"+id+"'";
result = statement.executeUpdate(sql);
} catch (Exception e) {
e.printStackTrace();
}finally {
if (con!=null){
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (statement!=null){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
return result;
}
}
service:
package service;
import domain.Student;
import java.util.ArrayList;
public interface StudentService {
//查询所有学生信息
ArrayList<Student> findAll();
//条件查询，根据id获取学生信息
Student findById(Integer id);
//新增学生信息
int insert(Student stu);
//修改学生信息
int update(Student stu);
//删除学生信息
int delete(Integer id);
}
serviceImpl:
package service;
import dao.StudentDao;
import dao.StudentDaoImpl;
import domain.Student;
import java.util.ArrayList;
public class StudentServiceImpl implements StudentService{
private StudentDao dao=new StudentDaoImpl();
@Override
public ArrayList<Student> findAll() {
return dao.findAll();
}
@Override
public Student findById(Integer id) {
return dao.findById(id);
}
@Override
public int insert(Student stu) {
return dao.insert(stu);
}
@Override
public int update(Student stu) {
return dao.update(stu);
}
@Override
public int delete(Integer id) {
return dao.delete(id);
}
}
controller:
package controller;
import com.sun.xml.internal.bind.v2.model.core.ID;
import domain.Student;
import org.junit.Test;
import service.StudentService;
import service.StudentServiceImpl;
import java.util.ArrayList;
import java.util.Date;
public class StudentController {
private StudentService service=new StudentServiceImpl();
//查询所有学生信息
@Test
public void findAll(){
ArrayList<Student> list = service.findAll();
for (Student student:list){
System.out.println(student);
}
}
//条件查询，根据id获取学生信息
@Test
public void findById(){
Student student=service.findById(1);
System.out.println(student);
}
//新增学生信息
@Test
public void insert(){
Student student=new Student(5,"李薇",88,new Date());
int result = service.insert(student);
if (result!=0){
System.out.println("添加成功");
}else {
System.out.println("添加失败");
}
}
//修改学生信息
@Test
public void update(){
Student stu = service.findById(5);
stu.setName("李兔兔");
int result = service.update(stu);
if (result!=0){
System.out.println("更新成功");
}else {
System.out.println("更行失败");
}
}
//删除学生信息
@Test
public void delete(){
int result = service.delete(5);
if (result!=0){
System.out.println("删除成功");
}else {
System.out.println("删除失败");
}
}
}
