org.projectlombok
lombok
1.18.10
junit
junit
4.12
test
mysql
mysql-connector-java
8.0.28
package com.csdn.fruit.pojo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.io.Serializable;
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Fruit implements Serializable {
private Integer fid;
private String fname;
private Integer price;
private Integer fcount;
private String remark;
public Fruit(String fname, Integer price, Integer fcount, String remark) {
this.fname = fname;
this.price = price;
this.fcount = fcount;
this.remark = remark;
}
@Override
public String toString() {
return fname + "\t\t" + price + "\t\t" + fcount + "\t\t" + remark;
}
}
jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql:///fruitdb
jdbc.user=root
jdbc.pwd=123456
package com.csdn.mymvc.dao;
import com.csdn.mymvc.util.ClassUtil;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
public abstract class BaseDao {
private String DRIVER;
private String URL;
private String USER;
private String PWD;
private String entityClassName;
public BaseDao() {
// this 是谁？ this代表的是 FruitDaoImpl 的实例对象，因为 BaseDao是抽象类，不能直接创建对象，所以 new 的是它的子类对象 FruitDaoImpl
// this.getClass() 获取的是 FruitDaoImpl 的Class对象
// getGenericSuperclass() 获取到的是：BaseDao
// Type 是顶层接口，表示所有的类型。它有一个子接口：ParameterizedType
ParameterizedType genericSuperclass = (ParameterizedType) this.getClass().getGenericSuperclass();
// Actual:实际的
// getActualTypeArguments() 获取实际的类型参数
Type[] actualTypeArguments = genericSuperclass.getActualTypeArguments();
Type actualTypeArgument = actualTypeArguments[0];
// System.out.println(actualTypeArgument.getTypeName());//com.csdn.fruit.pojo.Fruit
entityClassName = actualTypeArgument.getTypeName();
loadJdbcProperties();
}
//加载jdbc.properties文件
private void loadJdbcProperties() {
try {
InputStream inputStream = getClass().getClassLoader().getResourceAsStream("jdbc.properties");
Properties properties = new Properties();
properties.load(inputStream);
DRIVER = properties.getProperty("jdbc.driver", "com.mysql.cj.jdbc.Driver");
URL = properties.getProperty("jdbc.url", "jdbc:mysql:///fruitdb");
USER = properties.getProperty("jdbc.user", "root");
PWD = properties.getProperty("jdbc.pwd", "123456");
} catch (IOException e) {
throw new RuntimeException(e);
}
}
private Connection getConn() {
try {
Class.forName(DRIVER);
return DriverManager.getConnection(URL, USER, PWD);
} catch (ClassNotFoundException | SQLException e) {
throw new RuntimeException(e);
}
}
private void close(Connection conn, PreparedStatement psmt, ResultSet rs) {
try {
if (rs != null) {
rs.close();
}
if (psmt != null) {
psmt.close();
}
if (conn != null && !conn.isClosed()) {
conn.close();
}
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
//抽取执行更新方法
//执行更新，返回影响行数
protected int executeUpdate(String sql, Object... params) {
PreparedStatement psmt = null;
Connection conn = null;
try {
conn = getConn();
psmt = conn.prepareStatement(sql);
setParams(psmt, params);
return psmt.executeUpdate();
} catch (SQLException e) {
throw new RuntimeException(e);
} finally {
close(conn, psmt, null);
}
}
//设置参数
private void setParams(PreparedStatement psmt, Object... params) throws SQLException {
if (params != null && params.length > 0) {
for (int i = 0; i < params.length; i++) {
psmt.setObject(i + 1, params[i]);
}
}
}
//执行查询，返回集合
protected List executeQuery(String sql, Object... params) {
List list = new ArrayList<>();
Connection conn = null;
PreparedStatement psmt = null;
ResultSet rs = null;
try {
conn = getConn();
psmt = conn.prepareStatement(sql);
setParams(psmt, params);
rs = psmt.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();//元数据,结果集的结构数据
while (rs.next()) {
//T t = new T(); T仅仅是一个符号，所以不能 new
T t = (T) ClassUtil.createInstance(entityClassName);
int columnCount = rsmd.getColumnCount();//获取结果集的列的数据
//jdbc中都是从 1 开始，所以要把 i 改成 从 1 开始
for (int i = 1; i <= columnCount; i++) {
//假设循环 5 次，得到 5 个值，应该对应的是一个对象的 5 个属性的值
String columnName = rsmd.getColumnLabel(i);
Object columnValue = rs.getObject(i);
//给 t 这个对象的 columnName 属性赋 columnValue 值
ClassUtil.setProperty(t, columnName, columnValue);
}
list.add(t);
}
return list;
} catch (SQLException e) {
throw new RuntimeException(e);
} finally {
close(conn, psmt, rs);
}
}
protected T load(String sql, Object... params) {
Connection conn = null;
PreparedStatement psmt = null;
ResultSet rs = null;
try {
conn = getConn();
psmt = conn.prepareStatement(sql);
setParams(psmt, params);
rs = psmt.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();//元数据,结果集的结构数据
if (rs.next()) {
//T t = new T(); T仅仅是一个符号，所以不能 new
T t = (T) ClassUtil.createInstance(entityClassName);
int columnCount = rsmd.getColumnCount();//获取结果集的列的数据
//jdbc中都是从 1 开始，所以要把 i 改成 从 1 开始
for (int i = 1; i <= columnCount; i++) {
//假设循环 5 次，得到 5 个值，应该对应的是一个对象的 5 个属性的值
String columnName = rsmd.getColumnLabel(i);
Object columnValue = rs.getObject(i);
//给 t 这个对象的 columnName 属性赋 columnValue 值
ClassUtil.setProperty(t, columnName, columnValue);
}
return t;
}
} catch (SQLException e) {
throw new RuntimeException(e);
} finally {
close(conn, psmt, rs);
}
return null;
}
}
package com.csdn.mymvc.util;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
public class ClassUtil {
public static Object createInstance(String entityClassName) {
try {
return Class.forName(entityClassName).getDeclaredConstructor().newInstance();
} catch (InstantiationException | IllegalAccessException | InvocationTargetException | NoSuchMethodException |
ClassNotFoundException e) {
throw new RuntimeException(e);
}
}
public static void setProperty(Object instance, String propertyName, Object propertyValue) {
Class aClass = instance.getClass();
try {
Field field = aClass.getDeclaredField(propertyName);
field.setAccessible(true);
field.set(instance, propertyValue);
} catch (NoSuchFieldException | IllegalAccessException e) {
throw new RuntimeException(e);
}
}
}
package com.csdn.fruit.dao;
import com.csdn.fruit.pojo.Fruit;
import java.util.List;
//dao ：Data Access Object 数据访问对象
//接口设计
public interface FruitDao {
void addFruit(Fruit fruit);
void delFruit(String fname);
void updateFruit(Fruit fruit);
List getFruitList();
Fruit getFruitByFname(String fname);
}
package com.csdn.fruit.dao.impl;
import com.csdn.fruit.dao.FruitDao;
import com.csdn.fruit.pojo.Fruit;
import com.csdn.mymvc.dao.BaseDao;
import java.util.List;
public class FruitDaoImpl extends BaseDao implements FruitDao {
@Override
public void addFruit(Fruit fruit) {
String sql = "insert into t_fruit values (0,?,?,?,?)";
super.executeUpdate(sql, fruit.getFname(), fruit.getPrice(), fruit.getFcount(), fruit.getRemark());
}
@Override
public void delFruit(String fname) {
String sql = "delete from t_fruit where fname=?";
super.executeUpdate(sql, fname);
}
@Override
public void updateFruit(Fruit fruit) {
String sql = "update t_fruit set fcount=? where fname = ?";
super.executeUpdate(sql, fruit.getFcount(), fruit.getFname());
}
@Override
public List getFruitList() {
return super.executeQuery("select * from t_fruit");
}
@Override
public Fruit getFruitByFname(String fname) {
return load("select * from t_fruit where fname = ?", fname);
}
}
package com.csdn.fruit.view;
import com.csdn.fruit.dao.FruitDao;
import com.csdn.fruit.dao.impl.FruitDaoImpl;
import com.csdn.fruit.pojo.Fruit;
import java.util.List;
import java.util.Scanner;
public class Menu {
Scanner input = new Scanner(System.in);
private FruitDao fruitDao = new FruitDaoImpl();
//显示主菜单
public int showMainMenu() {
System.out.println("================欢迎使用水果库存系统===================");
System.out.println("1.显示库存列表");
System.out.println("2.添加库存记录");
System.out.println("3.查看特定库存");
System.out.println("4.水果下架");
System.out.println("5.退出");
System.out.println("====================================================");
System.out.print("请选择：");
return input.nextInt();
}
//显示库存列表
public void showFruitList() {
List fruitList = fruitDao.getFruitList();
System.out.println("----------------------------------------------------");
System.out.println("名称\t\t单价\t\t库存\t\t备注");
if (fruitList == null || fruitList.size() <= 0) {
System.out.println("对不起，库存为空！");
} else {
/* fruitList.forEach(new Consumer() {
@Override
public void accept(Fruit fruit) {
System.out.println(fruit);
}
});*/
// fruitList.forEach(fruit -> System.out.println(fruit));
fruitList.forEach(System.out::println);
}
System.out.println("----------------------------------------------------");
}
//添加库存记录
public void addFruit() {
System.out.print("请输入水果名称：");
String fname = input.next();
Fruit fruit = fruitDao.getFruitByFname(fname);
if (fruit == null) {
System.out.print("请输入水果单价：");
Integer price = input.nextInt();
System.out.print("请输入水果库存：");
Integer fcount = input.nextInt();
System.out.print("请输入水果备注：");
String remark = input.next();
fruit = new Fruit(fname, price, fcount, remark);
fruitDao.addFruit(fruit);
} else {
System.out.print("请输入追加的库存量：");
Integer fcount = input.nextInt();
fruit.setFcount(fruit.getFcount() + fcount);
fruitDao.updateFruit(fruit);
}
System.out.println("添加成功！");
}
//查看特定库存记录
public void showFruitInfo() {
System.out.print("请输入水果名称：");
String fname = input.next();
Fruit fruit = fruitDao.getFruitByFname(fname);
if (fruit == null) {
System.out.println("对不起，没有找到对应的库存记录！");
} else {
System.out.println("----------------------------------------------------");
System.out.println("名称\t\t单价\t\t库存\t\t备注");
System.out.println(fruit);
System.out.println("----------------------------------------------------");
}
}
//水果下架
public void delFruit() {
System.out.print("请输入水果名称：");
String fname = input.next();
Fruit fruit = fruitDao.getFruitByFname(fname);
if (fruit == null) {
System.out.println("对不起，没有找到需要下架的库存记录！");
} else {
System.out.print("是否确认下架?（Y/N）");
String confirm = input.next();
if ("y".equalsIgnoreCase(confirm)) {
fruitDao.delFruit(fname);
}
}
}
//退出
public boolean exit() {
System.out.print("是否确认退出？（Y/N）");
String confirm = input.next();
boolean flag= !"y".equalsIgnoreCase(confirm);
return flag;
}
}
package com.csdn.fruit.view;
public class Client {
public static void main(String[] args) {
Menu m = new Menu();
boolean flag = true;
while (flag) {
int slt = m.showMainMenu();
switch (slt) {
case 1:
m.showFruitList();
break;
case 2:
m.addFruit();
break;
case 3:
m.showFruitInfo();
break;
case 4:
m.delFruit();
break;
case 5:
//方法设计时是否需要返回值，依据是：是否在调用的地方需要留下一些值用于再运算
flag = m.exit();
break;
default:
System.out.println("你不按套路出牌！");
break;
}
}
System.out.println("谢谢使用！再见！");
}
}
package com.csdn.dao.impl;
import com.csdn.fruit.dao.FruitDao;
import com.csdn.fruit.dao.impl.FruitDaoImpl;
import com.csdn.fruit.pojo.Fruit;
import org.junit.Test;
import java.util.List;
public class FruitDaoImplTest {
private FruitDao fruitDao = new FruitDaoImpl();
@Test
public void testAddFruit() {
Fruit fruit = new Fruit("香蕉", 7, 77, "波罗蜜是一种神奇的水果！");
fruitDao.addFruit(fruit);
}
@Test
public void testDelFruit() {
fruitDao.delFruit("哈密瓜");
}
@Test
public void testUpdateFruit() {
Fruit fruit = new Fruit("波罗蜜", 5, 1000, "好吃");
fruitDao.updateFruit(fruit);
}
@Test
public void testGetFruitList() {
List fruitList = fruitDao.getFruitList();
fruitList.stream().forEach(System.out::println);
}
@Test
public void testGetFruitByFname() {
Fruit fruit = fruitDao.getFruitByFname("波罗蜜");
System.out.println(fruit);
}
/*
// this 是谁？ this代表的是 FruitDaoImpl 的实例对象，因为 BaseDao是抽象类，不能直接创建对象，所以 new 的是它的子类对象 FruitDaoImpl
// this.getClass() 获取的是 FruitDaoImpl 的Class对象
// getGenericSuperclass() 获取到的是：BaseDao
// Type 是顶层接口，表示所有的类型。它有一个子接口：ParameterizedType
ParameterizedType genericSuperclass = (ParameterizedType) this.getClass().getGenericSuperclass();
// Actual:实际的
// getActualTypeArguments() 获取实际的类型参数
Type[] actualTypeArguments = genericSuperclass.getActualTypeArguments();
Type actualTypeArgument = actualTypeArguments[0];
// System.out.println(actualTypeArgument.getTypeName());//com.csdn.fruit.pojo.Fruit
entityClassName = actualTypeArgument.getTypeName();
loadJdbcProperties();
*/
@Test
public void testActualTypeArgument() {
//这个方法是用来测试 actualTypeArgument 实际返回的参数
}
}
