diff --git "a/34 \347\250\213\351\230\263/20230517JDBC/JDBC.md" "b/34 \347\250\213\351\230\263/20230517JDBC/JDBC.md" new file mode 100644 index 0000000000000000000000000000000000000000..310a7dac017c587f0a07efa3c2d6c2938ff7cf3e --- /dev/null +++ "b/34 \347\250\213\351\230\263/20230517JDBC/JDBC.md" @@ -0,0 +1,187 @@ +```mysql +CREATE DATABASE student_db CHARSET utf8; +USE student_db; +CREATE TABLE student ( + id int(11) NOT NULL, + name varchar(255) , + sex varchar(255) +); +Drop TABLE student; +INSERT into student VALUES +(1,"张三","男"), +(2,"李四","女"), +(3,"王五","男"); +``` + +```java +package D1; + +import java.sql.*; +import java.util.Scanner; + +public class JDBC { +// ### JDBC作业： +//1. MySQL中创建一个数据库student_db +//2. 库中创建student表 +//3. 表中数据如下 +//4. | 编号 | 姓名 | 性别 | +// | ---- | ---- | ---- | +// | 1 | 张三 | 男 | +// | 2 | 李四 | 女 | +// | 3 | 王五 | 男 | +//5. 编写java 4个类，分别实现以下功能 +// 1. 查询功能，查询student中所有数据 +// 2. 添加功能 +// 3. 修改功能 +// 4. 删除功能 +//6. 扩展题【预习题】 +// 1. 能否实现一个类中，用四个方法来实现上面4个类的功能 +// 2. 能否实现将查询的结果，封装成java对象 + public static void main(String[] args) { + out: + while (true) { + Scanner scanner = new Scanner(System.in); + System.out.println("输入你要的功能:\n" + + "\t1,查询功能\n" + + "\t2 添加功能\n" + + "\t3 修改功能\n" + + "\t4 删除功能\n" + + "\t5 退出"); + String choose = scanner.next(); + switch (choose) { + case "1": + System.out.println("你选择了查询功能"); + Inquire();//查询功能 + break; + case "2": + System.out.println("你选择了添加功能"); + Add(); //添加功能 + break; + case "3": + System.out.println("你选择了修改功能"); + Alter(); //修改功能 + break; + case "4": + System.out.println("你选择了删除功能"); + Delete(); //删除功能 + break; + case "5": + System.out.println("你选择了退出功能"); + break out; + default: + System.out.println("对不起,没有这个功能!"); + } + } + } + + public static void Add() { +// 添加功能 + try { + Class.forName("com.mysql.jdbc.Driver"); + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String username = "root"; + String password = "root"; + Connection connection = DriverManager.getConnection(url, username, password); + String Add = "insert into student values(4,'赵六','男')"; + Statement statement = connection.createStatement(); + int i = statement.executeUpdate(Add); + if (i > 0) { + System.out.println("添加成功，添加了" + i + "行"); + } else { + System.out.println("添加失败"); + } + connection.close(); + statement.close(); + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } catch (SQLException e) { + throw new RuntimeException(e); + } + } + + public static void Delete() { + // 删除功能 + try { + Class.forName("com.mysql.jdbc.Driver"); + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String usename = "root"; + String password = "root"; + Connection connection = DriverManager.getConnection(url, usename, password); + String delete = "delete from student where id=4"; + Statement statement = connection.createStatement(); + int i = statement.executeUpdate(delete); + if (i > 0) { + System.out.println("删除成功,删除了" + i + "行"); + } else { + System.out.println("删除失败!"); + } + connection.close(); + statement.close(); + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } catch (SQLException e) { + throw new RuntimeException(e); + } + } + + public static void Alter() { + // 修改功能 + try { + Class.forName("com.mysql.jdbc.Driver"); + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String usename = "root"; + String password = "root"; + Connection connection = DriverManager.getConnection(url, usename, password); + String alter = "update student set name='老六' where id=4"; + Statement statement = connection.createStatement(); + int i = statement.executeUpdate(alter); + if (i > 0) { + System.out.println("修改成功,修改了" + i + "行"); + } else { + System.out.println("修改失败!"); + } + connection.close(); + statement.close(); + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } catch (SQLException e) { + throw new RuntimeException(e); + } + } + + public static void Inquire() { + + try { +// 查询功能 +// 1.注册驱动 + Class.forName("com.mysql.jdbc.Driver"); +// 2.链接对象 + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String usename = "root"; + String password = "root"; + Connection connection = DriverManager.getConnection(url, usename, password); +// 3.SQL的内容 + String sql = "select *from student"; +// 4.获取执行SQL的内容 + Statement statement = connection.createStatement(); +// 5.运行SQL + ResultSet re = statement.executeQuery(sql);//只针对查询语句 +// 6.处理结果 + while (re.next()) { + int id = re.getInt(1); + String name = re.getString(2); + String sex = re.getString(3); + System.out.println("ID:" + id + " 姓名:" + name + " 性别:" + sex); + } +// 7.释放资源 + connection.close(); + statement.close(); + re.close(); + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } catch (SQLException e) { + throw new RuntimeException(e); + } + } +} +``` \ No newline at end of file diff --git "a/34 \347\250\213\351\230\263/20230520JDBC2/jdbc2.md" "b/34 \347\250\213\351\230\263/20230520JDBC2/jdbc2.md" new file mode 100644 index 0000000000000000000000000000000000000000..2734f43c136aab8047993e951db4f5646e652269 --- /dev/null +++ "b/34 \347\250\213\351\230\263/20230520JDBC2/jdbc2.md" @@ -0,0 +1,139 @@ +````java +//今天作业：使用新的执行SQL的对象，封装一个工具类，然后用这个工具类查询上次作业的数据库，实现将查询结果封装成学生对象，最后存入一个集合窗口，遍历之个集合的对象 + +```java +public class Studentdx { + private int id; + private String name; + private String sex; + + public Studentdx() { + } + + public Studentdx(int id, String name, String sex) { + this.id = id; + this.name = name; + this.sex = sex; + } + + 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 String getSex() { + return sex; + } + + public void setSex(String sex) { + this.sex = sex; + } +} +``` + +```java +import java.sql.*; +import java.util.ArrayList; + +public class Student { + private static final String url="jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + private static final String user="root"; + private static final String pass ="200311"; + + static { + try { + Class.forName("com.mysql.cj.jdbc.Driver"); + + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } + + } + + public static Connection link() throws SQLException { + Connection conn = DriverManager.getConnection(url, user, pass); + return conn; + } + //查询 + ArrayList list = new ArrayList<>(); + public static ArrayList Query(String sql,ArrayList list,String ...flop) throws SQLException { + Connection conn = link(); + PreparedStatement ps = conn.prepareStatement(sql); + for (int i = 0; i < flop.length; i++) { + ps.setString((i+1),flop[i]); + } + ResultSet rs = ps.executeQuery(); + while (rs.next()){ + Studentdx stu = new Studentdx(); + stu.setId(rs.getInt("id")); + stu.setName(rs.getString("name")); + stu.setSex(rs.getString("sex")); + list.add(stu); + } + return list; + } + //添加,删除,修改 + public static int update(String sql,String ...flop) throws SQLException { + Connection conn = link(); + PreparedStatement ps = conn.prepareStatement(sql); + for (int i = 0; i < flop.length; i++) { + ps.setString((i+1),flop[i]); + } + int i = ps.executeUpdate(); + return i; + } + //释放 + public static void release(Connection conn,PreparedStatement ps,ResultSet rs) throws SQLException { + if (rs!=null){ + rs.close(); + } + if (ps!=null){ + ps.close(); + } + if (conn!=null){ + conn.close(); + } + } + public static void release(Connection conn,PreparedStatement ps) throws SQLException { + if (ps!=null){ + ps.close(); + } + if (conn!=null){ + conn.close(); + } + } +} +``` + +```java +import java.sql.SQLException; +import java.util.ArrayList; + +public class Text2 { + public static void main(String[] args) throws SQLException { + //今天作业：使用新的执行SQL的对象，封装一个工具类， + // 然后用这个工具类查询上次作业的数据库，实现将查询结果封装成学生对象， + // 最后存入一个集合窗口，遍历之个集合的对象 + ArrayList list = new ArrayList<>(); + String sql = "select * from student"; + ArrayList liste = Student.Query(sql, list); + System.out.println("id\t姓名\t性别"); + for (int i = 0; i < liste.size(); i++) { + Studentdx stu = liste.get(i); + System.out.println(stu.getId()+"\t"+stu.getName()+"\t"+stu.getSex()); + } + } +} +```` +