java学习笔记之分层增删改查

增删改查

一.准备jar包

　　数据库驱动包

　　DBUtils包

　　C3P0连接池 的jar包

二.配置好C3P0的配置文件

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
    <!-- 默认配置 -->
    <default-config>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql:///day26</property>
        <property name="user">root</property>
        <property name="password">root</property>
        
        <property name="automaticTestTable">con_test</property>
        <property name="checkoutTimeout">30000</property>
        <property name="idleConnectionTestPeriod">30</property>
        <property name="initialPoolSize">10</property>
        <property name="maxIdleTime">30</property>
        <property name="maxPoolSize">100</property>
        <property name="minPoolSize">10</property>
        <property name="maxStatements">200</property>
        <user-overrides user="test-user">
            <property name="maxPoolSize">10</property>
            <property name="minPoolSize">1</property>
            <property name="maxStatements">0</property>
        </user-overrides>
    </default-config> <!-- This app is massive! -->
    <!-- 命名的配置 -->
    <named-config name="my">
        <property name="acquireIncrement">50</property>
        <property name="initialPoolSize">100</property>
        <property name="minPoolSize">50</property>
        <property name="maxPoolSize">1000</property> <!-- intergalactoApp adopts a different approach to configuring statement 
            caching -->
        <property name="maxStatements">0</property>
        <property name="maxStatementsPerConnection">5</property> <!-- he's important, but there's only one of him -->
        <user-overrides user="master-of-the-universe">
            <property name="acquireIncrement">1</property>
            <property name="initialPoolSize">1</property>
            <property name="minPoolSize">1</property>
            <property name="maxPoolSize">5</property>
            <property name="maxStatementsPerConnection">50</property>
        </user-overrides>
    </named-config>
</c3p0-config>

 三.准备好工具类

　　ThreadLocal工具类：

import java.sql.Connection;
import java.sql.SQLException;

public class ConnectionManager {
    private  static ThreadLocal<Connection> tl=new ThreadLocal<>();
    public static Connection getConnection() throws SQLException{
        Connection  con=tl.get();
        if(con==null){
            con=MyC3P0Utils.getConnection();
            tl.set(con);
        }
        return con;
    }
    //开启事务
    public static void begin() throws SQLException{
        getConnection().setAutoCommit(false);
    }
    //提交事务
    public static void commit() throws SQLException{
        getConnection().commit();
    }
    //回滚事务
    
    public static void rollback() throws SQLException{
        getConnection().rollback();
    }
    //关闭资源
    public static void close() throws SQLException{
        getConnection().close();
    }
    
}

C3P0:

import java.sql.Connection;
import java.sql.SQLException;
import javax.sql.DataSource;
import com.mchange.v2.c3p0.ComboPooledDataSource;
public class MyC3P0Utils {
    private static DataSource dataSource=new ComboPooledDataSource();
    public static DataSource getDataSource(){
        return dataSource;
    }
    public static Connection getConnection() throws SQLException{
        return dataSource.getConnection();
    }

}

四.Dao层代码：

public class ProductDao {
    /**
     * 查询所有数据
     * @return  Product泛型的List集合
     * @throws SQLException
     */
    public List<Products> findAll() throws SQLException{
        QueryRunner qr = new QueryRunner(MyC3P0Utils.getDataSource());
        List<Products> list = qr.query("select * from products",new BeanListHandler<>(Products.class));
        return list;
    }
    /**
     * 通过id查找数据
     * @param id
     * @return
     * @throws SQLException
     */
    public Products findById(int id) throws SQLException{
        QueryRunner qr = new QueryRunner(MyC3P0Utils.getDataSource());
        Products product = qr.query("select * from products where pid=?",new BeanHandler<>(Products.class),id);
        return product;
    }
    /**
     * 插入数据
     * @param products  products类型的对象
     * @return  影响行数
     * @throws SQLException
     */
    public int  insertData(Products products) throws SQLException{
        QueryRunner qr = new QueryRunner(MyC3P0Utils.getDataSource());
        Object[] objects={products.getPname(),products.getPrice(),products.getCategory_id()};
        int re = qr.update("insert into products values(null,?,?,?)",objects);
        return re;
    }
    /**
     * 修改数据
     * @param products
     * @return 影响的行数
     * @throws SQLException
     */
    public int updateData(Products products) throws SQLException{
        QueryRunner qr = new QueryRunner(MyC3P0Utils.getDataSource());
        Object[] objects={products.getPname(),products.getPrice(),products.getCategory_id(),products.getPid()};
        int re = qr.update("update products set pname= ? ,price=? ,category_id=? where pid=?",objects);
        return re;
    }
    /**
     * 通过i删除产品
     * @param pid 产品id
     * @return  受影响的行数
     * @throws SQLException
     */
    public int deleteData(int pid) throws SQLException{
        QueryRunner qr = new QueryRunner();
        int re = qr.update(ConnectionManager.getConnection(),"delete from products where pid =?",pid);
        return re;
    }

}

五.Service层代码：

public class ProductService {
    /**
     *查询所有
     * @return
     */
    public List<Products> findAll(){
        ProductDao productDao=new ProductDao();
        List<Products> list =null;
        try {
            list = productDao.findAll();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return list;
    }
    /**
     * 通过id 查询数据
     * @param id
     * @return
     */
    public Products findById(int id){
        ProductDao productDao=new ProductDao();
        Products product=null;
        try {
             product = productDao.findById(id);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return product;
        
    }
    /**
     * 插入数据
     * @param products
     * @return
     */
    public int insertData(Products products){
        ProductDao productDao=new ProductDao();
        int re=-1;
        try {
            re = productDao.insertData(products);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return re;
    }
    /**
     * 修改数据
     * @param products
     * @return
     */
    public int updateData(Products products){
        ProductDao productDao=new ProductDao();
        int re=-1;
        try {
            re = productDao.updateData(products);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return re;
        
    }
    /**
     * 通过pid删除数据
     * @param pid
     * @return
     */
    public int deleteData(int pid){
        ProductDao productDao=new ProductDao();
        int re= -1;
        try {
            re = productDao.deleteData(pid);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return re;
    }
    
    public boolean deleteAll(HashSet<Integer> set){
        ProductDao productDao=new ProductDao();
        boolean flag=true;
        try {
            ConnectionManager.begin();
            for (Integer pid : set) {
        
                int re = productDao.deleteData(pid);
                
                if(!(re>0)){
                    flag=false;
                    break;
                }
            }
            if(flag){
                ConnectionManager.commit();
                return true;
            }else{
                ConnectionManager.rollback();
                return false;
            }
        } catch (SQLException e) {
                // TODO Auto-generated catch block
            
            try {
                ConnectionManager.rollback();
            } catch (SQLException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
        }finally{
            try {
                ConnectionManager.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return false;
    }
    

}

六 web层代码：

public class ProductWeb {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        while(true){
            System.out.println("请输入你的选择:");
            System.out.println("I:插入、U:修改、D:删除、DA:批量删除、QI：根据id查询、FA：查询所有、Q:退出");
            String string=scanner.nextLine().toUpperCase();
            
            switch (string) {
                case "I":
                    insertData(scanner);
                    break;
                case "U":
                    updateDate(scanner);
                    break;
                case "D":
                    deleteData(scanner);
                    break;
                case "DA":
                    deleteAll(scanner);
                    break;
                case "QI":
                    findById(scanner);
                    break;
                case "FA":
                    //查询所有
                    findAll();
                    break;
                case "Q":
                    System.out.println("是否要退出？（y/n）");
                    String s1 = scanner.nextLine();
                    if("y".equalsIgnoreCase(s1)){
                        System.exit(0);
                    }
                    break;
                default:
                    break;
            }
            
        
        }
        
    }
    /**
     * 批量删除
     * @param scanner
     */
    private static void deleteAll(Scanner scanner) {
        // TODO Auto-generated method stub
        HashSet<Integer> set =new HashSet<>();
        ProductService productService=new ProductService();
        String regex="[1-9]([0-9]*)";
        while(true){
            System.out.println("请输入删除产品pid(输入-1停止)");
        /*    String str=scanner.nextLine();
            if(!str.matches(regex)){
                System.out.println("不符合规则");
                continue;
            }
            int pid = Integer.parseInt(str);*/
            int pid =Integer.parseInt(scanner.nextLine());
            if(pid==-1){
                break;
            }
            Products product = productService.findById(pid);
            if(product==null){
                System.out.println("没有该条数据");
                continue;
            }
            System.out.println(product);
            set.add(pid);
        }
        System.out.println("你要删除的数据条数是"+set.size());
        System.out.println("请确认是否要删除？（y/n）");
        String choice = scanner.nextLine();
        if("y".equalsIgnoreCase(choice)){
            boolean flag = productService.deleteAll(set);
            if(flag){
                System.out.println("删除成功");
            }else {
                System.out.println("删除失败");
            }
        }
        
    }
    /**
     * 通过id删除
     * @param scanner
     */
    private static void deleteData(Scanner scanner) {
        // TODO Auto-generated method stub
        System.out.println("请输入要删除产品的id");
        String regex="[1-9]([0-9]*)";
        String str1 = scanner.nextLine();
        if(!str1.matches(regex)){
            System.out.println("输入格式不符合");
            return;
        }
        int pid = Integer.parseInt(str1);
        ProductService productService=new ProductService();
        Products product = productService.findById(pid);
        if(product==null){
            System.out.println("没有数据");
            return;
        }
        System.out.println("你要删除的产品数据是，确定要删除吗？（y/n）");
        System.out.println(product);
        String choice = scanner.nextLine();
        if(!"y".equalsIgnoreCase(choice)){
            System.out.println("输入有误，返回菜单");
            return;
        }
        int re = productService.deleteData(pid);
        if(re>0){
            System.out.println("删除成功");
        }else {
            System.out.println("删除失败");
        }
    }
    /**
     * 修改产品
     * @param scanner
     */
    private static void updateDate(Scanner scanner) {
        // TODO Auto-generated method stub
        System.out.println("请输入要修改产品的pid");
        String regex="[1-9]([0-9]*)";
        String str = scanner.nextLine();
        if(!str.matches(regex)){
            System.out.println("格式不正确");
            return ;
        }
        int pid = Integer.parseInt(str);
        ProductService productService=new ProductService();
        Products product = productService.findById(pid);
        if(product==null){
            System.out.println("没有数据");
            return;
        }
        System.out.println("请输入新的名字");
        String pname=scanner.nextLine();
        System.out.println("请输入新的价格");
        double price = Double.parseDouble(scanner.nextLine());
        System.out.println("请输入类别，（1是电子，2是服装，3是化妆品）");
        int category_id = Integer.parseInt(scanner.next());
        product.setCategory_id(category_id);
        product.setPname(pname);
        product.setPrice(price);
        int re = productService.updateData(product);
        if(re>0){
            System.out.println("修改成功");
        }else{
            System.out.println("修改失败");
        }
    }
    /**
     * 插入数据
     * @param scanner
     */
    private static void insertData(Scanner scanner) {
        System.out.println("请输入产品名称");
        String pname = scanner.nextLine();
        System.out.println("请输入价格");
        double price = Double.parseDouble(scanner.nextLine());
        System.out.println("请输入类别，（1是电子，2是服装，3是化妆品）");
        int cate = Integer.parseInt(scanner.next());
        ProductService productService=new ProductService();
        Products products=new Products();
        products.setPname(pname);
        products.setPrice(price);
        products.setCategory_id(cate);
        int re = productService.insertData(products);
        if(re>0){
            System.out.println("插入成功");
        }
    }
    /**
     * 通过id 查询数据
     * @param scanner
     */
    private static void findById(Scanner scanner) {
        // TODO Auto-generated method stub
        System.out.println("请输入要查询的pid");
        
        String regex="[1-9]([0-9]*)";
        String str = scanner.nextLine();
        if(!str.matches(regex)){
            System.out.println("输入格式不符合");
            return;
        }
        int pid = Integer.parseInt(str);
        ProductService productService=new ProductService();
        Products product = productService.findById(pid);
        if(product==null){
            System.out.println("没有数据");
            return;
        }
        System.out.println(product);
    }
    /**
     * 查询所有
     */
    private static void findAll() {
        ProductService productService=new ProductService();
        List<Products> list = productService.findAll();
        if(list==null){
            System.out.println("查询出错");
            return; 
        }
        if(list.size()==0){
            System.out.println("没有数据");
            return;
        }
        for (Products products : list) {
            System.out.println(products.getPid()+"	"+products.getPname()+"	"+products.getPrice()+"	"+products.getCategory_id());
        }
    }
}

七.javaBean类

public class Products {
    private Integer pid;
    private String pname;
    private double price ;
    private int category_id;
    public Integer getPid() {
        return pid;
    }
    public void setPid(Integer pid) {
        this.pid = pid;
    }
    public String getPname() {
        return pname;
    }
    public void setPname(String pname) {
        this.pname = pname;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    public int getCategory_id() {
        return category_id;
    }
    public void setCategory_id(Integer category_id) {
        this.category_id = category_id;
    }
    public Products(Integer pid, String pname, double price, int category_id) {
        super();
        this.pid = pid;
        this.pname = pname;
        this.price = price;
        this.category_id = category_id;
    }
    @Override
    public String toString() {
        return "Products [pid=" + pid + ", pname=" + pname + ", price=" + price + ", category_id=" + category_id + "]";
    }
    public Products() {
        super();
        // TODO Auto-generated constructor stub
    }

}