diff --git "a/07 \345\206\257\345\273\272\347\250\213/20230519 jdbc\344\275\234\344\270\232.md.txt" "b/07 \345\206\257\345\273\272\347\250\213/20230519 jdbc\344\275\234\344\270\232.md.txt" new file mode 100644 index 0000000000000000000000000000000000000000..666be31062ef5ad684e5b649a7f5f69bcfbe132b --- /dev/null +++ "b/07 \345\206\257\345\273\272\347\250\213/20230519 jdbc\344\275\234\344\270\232.md.txt" @@ -0,0 +1,166 @@ +### 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 | + + ~~~MySQL + create database student_db default char set utf8; + use student_db; + create table student_db ( + id int , + name varchar(10), + sex char + ); + insert into student_db values + (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 + + ~~~java + import java.sql.*; + + public class Jdbc { + public static void main(String[] args) { + try { + select();//查询 + update();//修改 + insert();//添加 + delete();//删除 + } catch (SQLException e) { + throw new RuntimeException(e); + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } + + } + public static void select() throws SQLException, ClassNotFoundException { + //1.注册驱动 + Class.forName("com.mysql.jdbc.Driver"); + //2.获取连接对象 + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String username = "root"; + String password = "root"; + Connection conn = DriverManager.getConnection(url,username,password); + //3.定义SQL + String sql = "select * from sonyang;"; + + //4.获取执行SQL + Statement st = conn.createStatement(); + + //5.执行SQL + ResultSet rs = st.executeQuery(sql); + //6.处理返回结果 + System.out.println("id "+"name"); + while (rs.next()){ + int id = rs.getInt("id"); + String name = rs.getString("name"); + System.out.println(id+" "+name); + } + //7.释放资源 + rs.close(); + st.close(); + conn.close(); + } + public static void update() throws SQLException, ClassNotFoundException { + //1.注册驱动 + Class.forName("com.mysql.jdbc.Driver"); + //2.获取连接对象 + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String username = "root"; + String password = "root"; + Connection conn = DriverManager.getConnection(url,username,password); + //3.定义SQL + String sql = "update sonyang set name = '宋扬2号'where id=1"; + + //4.获取执行SQL + Statement st = conn.createStatement(); + + //5.执行SQL + int i = st.executeUpdate(sql); + //6.处理返回结果 + if (i>0){ + System.out.println("修改成功"); + }else { + System.out.println("修改失败"); + } + //7.释放资源 + st.close(); + conn.close(); + } + public static void insert() throws ClassNotFoundException, SQLException { + //1.注册驱动 + Class.forName("com.mysql.jdbc.Driver"); + //2.获取连接对象 + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String username = "root"; + String password = "root"; + Connection conn = DriverManager.getConnection(url,username,password); + //3.定义SQL + String sql = "insert into sonyang values (2,'邓琪plus')"; + //4.获取执行SQL + Statement st = conn.createStatement(); + + //5.执行SQL + int i = st.executeUpdate(sql); + //6.处理返回结果 + if (i>0){ + System.out.println("添加"+i+"行数据成功"); + }else { + System.out.println("添加失败"); + } + //7.释放资源 + st.close(); + conn.close(); + } + public static void delete() throws ClassNotFoundException, SQLException { + //1.注册驱动 + Class.forName("com.mysql.jdbc.Driver"); + //2.获取连接对象 + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + String username = "root"; + String password = "root"; + Connection conn = DriverManager.getConnection(url,username,password); + //3.定义SQL + String sql = "delete from sonyang where name='张三'"; + //4.获取执行SQL + Statement st = conn.createStatement(); + //5.执行SQL + int i = st.executeUpdate(sql); + //6.处理返回结果 + if (i>0){ + System.out.println("删除了"+i+"行数据成功"); + }else { + System.out.println("删除失败"); + } + //7.释放资源 + st.close(); + conn.close(); + + } + } + + ~~~ \ No newline at end of file diff --git "a/07 \345\206\257\345\273\272\347\250\213/20230520 \344\275\234\344\270\232.md.txt" "b/07 \345\206\257\345\273\272\347\250\213/20230520 \344\275\234\344\270\232.md.txt" new file mode 100644 index 0000000000000000000000000000000000000000..80d0227aa26600648503028c9573ba59cc9302a6 --- /dev/null +++ "b/07 \345\206\257\345\273\272\347\250\213/20230520 \344\275\234\344\270\232.md.txt" @@ -0,0 +1,105 @@ +````java +//JDBC工具类 +import java.sql.*; + +public class Jdbc { + //注册+连接 + private Connection conn() { + try { + Class.forName("com.mysql.jdbc.Driver"); + String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEchoing=utf8"; + Connection conn = DriverManager.getConnection(url, "root", "root"); + return conn; + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } catch (SQLException e) { + throw new RuntimeException(e); + } + } + + //查询 + ResultSet select(String sql){ + try { + PreparedStatement pst = conn().prepareStatement(sql); + ResultSet re = pst.executeQuery(); + return re; + } catch (SQLException e) { + throw new RuntimeException(e); + } + } +} +``` + +```java +//学生对象 +public class Student { + private int id; + private String name; + private String sex; + + public Student() { + } + + public Student(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 +//测试类 +import java.sql.*; +import java.util.ArrayList; + +public class Test { + public static void main(String[] args) { + Jdbc jdbc = new Jdbc(); + ResultSet re = jdbc.select("select * from student"); + ArrayList stu = new ArrayList<>(); + try { + while (re.next()) { + int id = re.getInt(1); + String name = re.getString(2); + String sex = re.getString(3); + Student s = new Student(id, name, sex); + stu.add(s); + } + } catch (SQLException e) { + throw new RuntimeException(e); + } + + System.out.println("ID\t\t姓名\t\t性别"); + for (int i = 0; i < stu.size(); i++) { + Student s = stu.get(i); + System.out.println(s.getId()+"\t\t"+s.getName()+"\t\t"+s.getSex()); + } + } +} +```` +