创建学生类
package com.jdbc.po;
import java.util.Date;
public class Student {
//建立私有属性的id，name，age，sex，birthday
//属性需要与mysql数据库中的一致
private int id;
private String name;
private int age;
private int sex;
private Date birthday;
//建立私有属性访问器
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public int getSex() {
return sex;
}
public void setSex(int sex) {
this.sex = sex;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "学生信息 [id=" + id + ", 姓名=" + name + ", 年龄=" + age + ", 性别=" + sex + ", 出生日期=" + birthday
+ "]";
}
}
创建增删改查方法类
package com.jdbc.dao;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import com.jdbc.po.Student;
public class StudentDao {
// 插入学生对象
public void insert(Student stu) {
// ?代表占位符
//重点：mysql插入数据语句
String sql = "insert into student(name,age,s书写格式ex,birthday) values(?,?,?,?)";
Connection conn = DBUtils.getConnection();
PreparedStatement pst = null;
try {
pst = conn.prepareStatement(sql);
pst.setString(1, stu.getName());
pst.setInt(2, stu.getAge());
pst.setInt(3, stu.getSex());
// Date类型的数据插入
// 此处Date为父类
Date birthday = stu.getBirthday();
// util得到一个毫秒数
long millSec = birthday.getTime();
// 构建一个sql包下的Date
java.sql.Date sqlDate = new java.sql.Date(millSec);
// 这个方法需要一个子类sql包下的Date
pst.setDate(4, sqlDate);
// 执行插入语句
pst.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
} finally {
DBUtils.closeConnection(conn, pst,null);
}
}
// 修改学生对象
public void modify(Student stu) {
String sql = "update student set name = ?, age = ?, sex = ?, birthday = ? where id = ?";
// 建立连接
Connection conn = DBUtils.getConnection();
// 初始化一个语句对象
PreparedStatement pst = null;
try {
pst = conn.prepareStatement(sql);
pst.setString(1, stu.getName());
pst.setInt(2, stu.getAge());
pst.setInt(3, stu.getSex());
pst.setInt(5, stu.getId());
Date birthday = stu.getBirthday();
long millSec = birthday.getTime();
java.sql.Date sqlDate = new java.sql.Date(millSec);
pst.setDate(4, sqlDate);
pst.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
} finally {
DBUtils.closeConnection(conn, pst, null);
}
}
// 根据主键删除学生对象
public void delete(int id) {
// ?代表占位符
String sql = "delete from student where id = ?";
// 初始化一个链接对象
Connection conn = DBUtils.getConnection();
// 初始化一个语句对象
PreparedStatement pst = null;
try {
// 得到了一个预处理的语句对象：提高效率
pst = conn.prepareStatement(sql);
// 给参数？
pst.setInt(1, id);
// 调用sql语句的执行(新增，修改，删除)
pst.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
} finally {
DBUtils.closeConnection(conn, pst, null);
}
}
// 查询学生列表
// 通过集合的方法
public List getALL() {
//数据库查询语句
String sql = "select * from student";
//建立连接
Connection conn = DBUtils.getConnection();
List list = new ArrayList();
PreparedStatement pst = null;
ResultSet rs = null;
try {
pst = conn.prepareStatement(sql);
rs = pst.executeQuery();
while (rs.next()) {
// 利用多态获取值
Student stu = new Student();
stu.setId(rs.getInt("id"));
stu.setName(rs.getString("name"));
stu.setSex(rs.getInt("sex"));
stu.setAge(rs.getInt("age"));
stu.setBirthday(rs.getDate("birthday"));
list.add(stu);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return list;
}
//根据ID查询学生
public Student getById(int id){
String sql = "select * from student where id = ?";
Connection conn = DBUtils.getConnection();
PreparedStatement pst = null;
Student stu = new Student();
ResultSet rs = null;
//没有查询前，返回值为null
Student result = null;
try {
pst = conn.prepareStatement(sql);
pst.setInt(1, id);
rs = pst.executeQuery();
while(rs.next()){
result = new Student();
result.setId(rs.getInt("id"));
result.setName(rs.getString("name"));
result.setSex(rs.getInt("sex"));
result.setAge(rs.getInt("age"));
result.setBirthday(rs.getDate("birthday"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return result;
}
public List getDynQuery(Student query){
//where 1 = 1 类似于boolean 表示 - 真(但是不能加true)
String sql = "select * from student where 1 = 1";
Connection conn = DBUtils.getConnection();
//Statement和preparedStatement的区别
Statement st = null;
ResultSet rs = null;
List list = new ArrayList();
try {
st = conn.createStatement();
//独立的if
//为什么只有ID，name，age
if(query.getId() != 0){
sql += "and id =" + query.getId();
}
//名字用模糊查询--查询格式
if(!query.getName().equals("0")){
sql += " and name like '%" + query.getName()+ "%'";
}if(query.getSex() != 0){
sql += "and age =" + query.getSex();
}
rs = st.executeQuery(sql);
while(rs.next()){
Student stu = new Student();
stu.setId(rs.getInt("id"));
stu.setName(rs.getString("name"));
stu.setSex(rs.getInt("sex"));
stu.setAge(rs.getInt("age"));
stu.setBirthday(rs.getDate("birthday"));
list.add(stu);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
DBUtils.closeConnection(conn, st, rs);
}
return list;
}
}
创建工具类
package com.jdbc.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
//通过建立工具类DBUtils来对连接数据库和断开数据库所写的功能代码进行提取，因为增删改查的方法内都需要进行连接和断开数据库
//通过提取来进行代码优化
public class DBUtils {
// 取得连接
//用static修饰的时候访问没有限制
public static Connection getConnection() {
String url = "jdbc:mysql://localhost:3306/jdbc";
String user = "root";
String password = "root";
Connection conn = null;
try {
// 引入数据库的连接驱动
Class.forName("com.mysql.jdbc.Driver");
// 连接数据库--需要(三个参数：连接地址 用户名 密码)
conn = DriverManager.getConnection(url, user, password);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
// 关闭连接
public static void closeConnection(Connection conn, Statement pst,ResultSet rs) {
try {
//加条件语句能
if (rs != null) {
rs.close();
}
if (pst != null) {
pst.close();
}
if (conn != null) {
conn.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
创建测试类
package com.jdbc.dao;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;
import java.util.Scanner;
import com.jdbc.po.Student;
public class TestPrepared {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
//创建一个StudentDao的对象
StudentDao dao = new StudentDao();
boolean flag = true;
while(flag){
System.out.println("请输入您的操作 1.插入 2.修改 3.删除 4.查询所有信息 5.根据id查询单条信息 6.根据输入的信息进行查询 7.退出");
int oper = input.nextInt();
switch(oper){
case 1:
System.out.println("请输入姓名");
String name = input.next();
System.out.println("请输入年龄");
int age = input.nextInt();
System.out.println("请输入性别");
int sex = input.nextInt();
System.out.println("请输入出生的年月日：yyyy-MM-dd");
String bir= input.next();
String[] birArr = bir.split("-");
Calendar c = Calendar.getInstance();
c.set(Integer.parseInt(birArr[0]), Integer.parseInt(birArr[1]), Integer.parseInt(birArr[2]));
Student stu = new Student();
stu.setAge(age);
stu.setName(name);
stu.setSex(sex);
//日期型的生日
stu.setBirthday(c.getTime());
dao.insert(stu);
break;
case 2:
System.out.println("请输入需要修改信息的ID");
int id2 = input.nextInt();
System.out.println("请输入修改后的姓名");
String name2 = input.next();
System.out.println("请输入修改后的年龄");
int age2 = input.nextInt();
System.out.println("请输入修改后的性别");
int sex2 = input.nextInt();
System.out.println("请输入修改后的出生的年月日：yyyy-MM-dd");
String bir2= input.next();
String[] birArr2 = bir2.split("-");
Calendar c2 = Calendar.getInstance();
c2.set(Integer.parseInt(birArr2[0]), Integer.parseInt(birArr2[1]), Integer.parseInt(birArr2[2]));
Student stu2 = new Student();
stu2.setId(id2);
stu2.setAge(age2);
stu2.setName(name2);
stu2.setSex(sex2);
stu2.setBirthday(c2.getTime());
dao.modify(stu2);
break;
case 3:
System.out.println("请输入要删除的id");
int id = input.nextInt();
dao.delete(id);
break;
case 4:
List list = dao.getALL();
//通过遍历输出
for(Student stu3: list){
System.out.println(stu3);
}
break;
case 5:
System.out.println("请输入要查询信息的id");
int id3 = input.nextInt();
Student result = dao.getById(id3);
System.out.println(result);
break;
case 6:
//
System.out.println("请输入要查询的ID");
int id4 = input.nextInt();
System.out.println("请输入要查询的名字");
String name3 = input.next();
System.out.println("请输入要查询的性别");
int sex3 = input.nextInt();
//
Student query = new Student();
query.setId(id4);
query.setName(name3);
query.setSex(sex3);
List list3 = dao.getDynQuery(query);
for(Student stu5: list3){
System.out.println(stu5);
}
break;
case 7:
flag = false;
break;
}
}
}
}
代码实现结果界面
插入数据
插入数据后mysql结果
修改数据
修改数据后mysql结果
删除数据
删除数据后mysql结果
根据id查询单条信息
根据输入的信息进行查询