MVC，JDBC

1.使用自己的话表述MVC。

MVC 由三个基本部分组成 - 模型（Model），视图（View）和控制器（Controller）。
-模型(Model)：包含一组数据的类和管理该数据的逻辑信息。
-View（视图）：包含显示逻辑，用于显示 Controller 提供给它的模型中的数据。
-Controller（控制器）:处理 Http 请求，调用模型，请选择一个视图来呈现该模型。

2.掌握JDBC的基本操作。 对book表中的数据进行增删改查； book表：id int，bookName varchar,price int,description varchar Book类：id int，bookName String ，price int，description String 提示：创建数据库连接工具类DBUtil类。

/*
* name:wyh
* 代码功能：book类
* 具体类、方法的作用：实例化book类
* 时间：2019年10月10日下午7:22:49
*
*/
public class Book {
private int id;
private String bookName;
private int price;
private String description;

public Book() {
}
public Book(int id, String bookName, int price, String description) {
	this.id = id;
	this.bookName = bookName;
	this.price = price;
	this.description = description;
}
public int getId() {
	return id;
}
public void setId(int id) {
	this.id = id;
}
public String getBookName() {
	return bookName;
}
public void setBookName(String bookName) {
	this.bookName = bookName;
}
public int getPrice() {
	return price;
}
public void setPrice(int price) {
	this.price = price;
}
public String getDescription() {
	return description;
}
public void setDescription(String description) {
	this.description = description;
}
public String toString() {
	return "Book [id=" + id + ", bookName=" + bookName + ", price=" + price + ", description=" + description+"]";
}

}

/*
* name:wyh
* 代码功能：数据库管理类
* 具体类、方法的作用：
* 时间：2019年10月10日下午7:24:20
*
*/
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;import com.mysql.jdbc.PreparedStatement;

/**
*

• 数据库连接工具类

*/
public class DBUtil {
//类加载只执行一次
static{
try {
Class.forName(“com.mysql.jdbc.Driver”);
} catch (ClassNotFoundException e) {

		e.printStackTrace();
	}
}
public static Connection getConnection(){
	String sql="jdbc:mysql://127.0.0.1:3306/jdbc?useUnicode=true&characterEncoding=UTF-8";
	Connection conn;
	try {
		conn = DriverManager.getConnection(sql,"root","1234");
		return conn;
	} catch (SQLException e) {
		
		e.printStackTrace();
		return null;
	}
	
}

public static void close(Connection conn){
	try {
		conn.close();
		
	} catch (SQLException e) {
		
		e.printStackTrace();
	}
}

public static void close(PreparedStatement ps){
	try {
		ps.close();
	} catch (SQLException e) {
		
		e.printStackTrace();
	}
	
}
public static void close(ResultSet rs){
	try {
		rs.close();
	} catch (SQLException e) {
		
		e.printStackTrace();
	}
	
}

}

/*
* name:wyh
* 代码功能：测试类
* 具体类、方法的作用：
* 时间：2019年10月10日下午7:23:44
*
*/
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.util.DBUtil;

public class TestJdbc {

public static void main(String[] args) {
	Book book=new Book(2, "javaee", 425, "面向对象编程");

// inserts(book);
selects();
// deleteid(4);
updates(book);
}
//查
public static Book selects(){
Connection conn = DBUtil.getConnection();
PreparedStatement pstmt;
Book book = new Book();
try {
pstmt = conn.prepareStatement(“select * from book”);
ResultSet rs = pstmt.executeQuery();
while (rs.next()) {
book.setId(rs.getInt(“id”));
book.setBookName(rs.getString(“bookName”));
book.setPrice(rs.getInt(“price”));
book.setDescription(rs.getString(“description”));

            System.out.println(book);
        }
    } catch (SQLException e) {
        
        e.printStackTrace();
    }

    return book;
}
   //增
   public static void inserts(Book book){
        Connection conn = DBUtil.getConnection();
        PreparedStatement pstmt;
        try {
            pstmt = conn.prepareStatement("insert into book(id,bookName,price,description) values(?,?,?,?)");
            pstmt.setInt(1, book.getId());
            pstmt.setString(2, book.getBookName());
            pstmt.setInt(3, book.getPrice());
			pstmt.setString(4, book.getDescription());
            pstmt.executeUpdate();
        } catch (SQLException e) {
            
            e.printStackTrace();
        }

    }
   //删
   public static void deleteid(int id){
    	Connection conn = DBUtil.getConnection();
        PreparedStatement pstmt;
        try {
            pstmt = conn.prepareStatement("delete from book where id=?");
            pstmt.setInt(1, id);
            pstmt.executeUpdate();
        } catch (SQLException e) {
            
            e.printStackTrace();
        }
    }
   //改
   public static void updates(Book book){
        Connection conn = DBUtil.getConnection();
        PreparedStatement pstmt;
        try {
            pstmt = conn.prepareStatement("update book set bookName=?,price=?,description=? where id=?");
            pstmt.setString(1, book.getBookName());
            pstmt.setInt(2, book.getPrice());
            pstmt.setString(3, book.getDescription());
            pstmt.setInt(4, book.getId());
            pstmt.executeUpdate();
        } catch (SQLException e) {
            
            e.printStackTrace();
        }

    }

}