17软工2班宁一健 JDBC Book类 JAVA第四次作业

1.使用自己的话表述MVC。
MVC是一种设计模式，在我们已学习的javaweb中，MVC中的M是指模型对应着JavaBean实体类、Dao,V是指视图对应值前端的页面HTML等，C是指控制器对应着Servlet。MVC模式让一个项目的代码分离，各司其职，便于开发和维护。并且让我们看代码的时候能清楚的知道每块代码的作用。
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。
（1）首先先建表如图

下面是代码：

package com.nyj.JDBC4;

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;
}
@Override
public String toString() {
return "Book [id=" + id + ", bookName=" + bookName + ", price=" + price + ", description=" + description + "]";
}

}

package com.nyj.JDBC4;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DBUtil {
static{
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
public static Connection getConnection(){
String sql="jdbc:mysql://localhost:3306/javahomework?useUnicode=true&characterEncoding=UTF-8";
Connection conn;
try {
conn = DriverManager.getConnection(sql, "root", "123456");
return conn;
} catch (SQLException e) {
// TODO Auto-generated catch block
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();
}
}

}

package com.nyj.JDBC4;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
/**
* 书本的增删改查功能
* @author 宁一健
*
*/

public class BookTest {

public static void main(String[] args) {
//		Book book = new Book();
//		book.setId(1004);
//		book.setBookName("java");
//		book.setPrice(50);
//		book.setDescription("好书");
//		saveBook(book);
//deleteBookById(1003);
//		updateBook(book);
//findBookById(1003);
fidBookByPrice(500);

}

/**
* 添加书本的方法
*/
public static void saveBook(Book book) {
Connection conn = DBUtil.getConnection();
PreparedStatement pstmt = null;
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());
int rs = pstmt.executeUpdate();
System.out.println(rs);
} catch (SQLException e) {
e.printStackTrace();
}finally {
try {
if(pstmt!=null)
pstmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

}

/**
* 删除书本的方法
*/
public static void deleteBookById(int id) {
Connection conn = DBUtil.getConnection();
PreparedStatement pstmt = null;
try {
pstmt = conn.prepareStatement("delete from book where id=?");
pstmt.setInt(1, id);
int rs = pstmt.executeUpdate();
System.out.println(rs);
} catch (SQLException e) {
e.printStackTrace();
}finally {
try {
if(pstmt!=null)
pstmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

}
/**
* 修改书本的方法   id
*
*/
public static void updateBook(Book book){
Connection conn = DBUtil.getConnection();
PreparedStatement pstmt = null;
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());
int rs = pstmt.executeUpdate();
System.out.println(rs);
} catch (SQLException e) {
e.printStackTrace();
}finally {
try {
if(pstmt!=null)
pstmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

}
/**
* 查询书本的方法   id
*/

public static Book findBookById(Integer id) {
Connection conn = DBUtil.getConnection();
PreparedStatement pstmt = null;
Book book = new Book();
try {
pstmt = conn.prepareStatement("select * from book where id=?");
pstmt.setInt(1, id);
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();
}finally {
try {
if (pstmt!=null)
pstmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

return book;
}
/**
* 查询书本的方法 price
*/
public static List<Book> fidBookByPrice(int price){
Connection conn = DBUtil.getConnection();
Book book = new Book();
List<Book> list = new ArrayList<>();
PreparedStatement pstmt = null;
try {
pstmt = conn.prepareStatement("select * from book where price =?");
pstmt.setInt(1, price);
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"));
list.add(book);
for(Book list2:list)
System.out.println(list2);
}
} catch (SQLException e) {
e.printStackTrace();
}finally {
try {
if(pstmt!=null)
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return list;

}

}