From eb3a42ce6e0a928cfe5cd4ff87d317d8e287fac7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E7=94=98=E5=90=AF=E8=88=AA?= Date: Fri, 19 May 2023 21:38:26 +0800 Subject: [PATCH] zy --- ...C\344\275\234\344\270\232 \357\274\232.md" | 211 ++++++++++++++++++ 1 file changed, 211 insertions(+) create mode 100644 "24 \347\224\230\345\220\257\350\210\252/\347\224\230\345\220\257\350\210\252 2023 05 19 JDBC\344\275\234\344\270\232 \357\274\232.md" diff --git "a/24 \347\224\230\345\220\257\350\210\252/\347\224\230\345\220\257\350\210\252 2023 05 19 JDBC\344\275\234\344\270\232 \357\274\232.md" "b/24 \347\224\230\345\220\257\350\210\252/\347\224\230\345\220\257\350\210\252 2023 05 19 JDBC\344\275\234\344\270\232 \357\274\232.md" new file mode 100644 index 0000000..1fc7b23 --- /dev/null +++ "b/24 \347\224\230\345\220\257\350\210\252/\347\224\230\345\220\257\350\210\252 2023 05 19 JDBC\344\275\234\344\270\232 \357\274\232.md" @@ -0,0 +1,211 @@ +### 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 + +```mysql +CREATE DATABASE student_db charset utf8; +USE student_db; +CREATE TABLE student ( + id INT, + name VARCHAR(10), + sex VARCHAR(2) +); +INSERT INTO student VALUES +(1, '张三', '男'), +(2, '李四', '女'), +(3, '王五', '男'); +/* +数据库 +*/ +``` + +```java +//学生类 +public class Student { + private int id; + private String name; + private String sex; +} + public Student(int id, String name, String gender) { + this.id = id; + this.name = name; + this.gender = gender; + } + + 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 getGender() { + return sex; + } + + public void setGender(String sex) { + this.sex = sex; + } + + @Override + public String toString() { + return "id: " + id + ", name: " + name + ", sex: " + sex; + } +} + +``` + +```java +import java.sql.*; +import java.util.ArrayList; +import java.util.List; + +public class StudentDao { + private static final String URL = "jdbc:mysql://localhost:3306/student_db"; + private static final String username = "root"; + private static final String password = "root"; + + public List cxAll() { + List students = new ArrayList<>(); + + try (Connection conn = DriverManager.getConnection(URL, username, password); + Statement stmt = conn.createStatement(); + ResultSet rs = stmt.executeQuery("SELECT * FROM student")) { + + while (rs.next()) { + int id = rs.getInt("id"); + String name = rs.getString("name"); + String gender = rs.getString("sex"); + Student student = new Student(id, name, sex); + students.add(student); + } + + } catch (SQLException e) { + e.printStackTrace(); + } + + return students; + } +//查询所有学生 + public boolean add(Student student) { + try (Connection conn = DriverManager.getConnection(URL, USER_NAME, PASSWORD); + PreparedStatement stmt = conn.prepareStatement("insert into student(name, sex) values (?, ?)")) { + + stmt.setString(1, student.getName()); + stmt.setString(2, student.getSex()); + int count = stmt.executeUpdate(); + + return count > 0; + + } catch (SQLException e) { + e.printStackTrace(); + } + + return false; + } +//修改学生信息 + public boolean update(Student student) { + try (Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD); + PreparedStatement stmt = conn.prepareStatement("UPDATE student SET name =? , sex = ? WHERE id = ?")) { + + stmt.setString(1, student.getName()); + stmt.setString(2, student.getGender()); + stmt.setInt(3, student.getId()); + int count = stmt.executeUpdate(); + + return count > 0; + + } catch (SQLException e) { + e.printStackTrace(); + } + + return false; + } + + public boolean delete(int id) { + try (Connection conn = DriverManager.getConnection(URL, USER_NAME, PASSWORD); + PreparedStatement stmt = conn.prepareStatement("DELETE FROM student WHERE id = ?")) { + + stmt.setInt(1, id); + int count = stmt.executeUpdate(); + + return count > 0; + + } catch (SQLException e) { + e.printStackTrace(); + } + + return false; + } +} +``` + +```java +//运行类 +import java.util.List; + +public class Main { + public static void main(String[] args) { + StudentDAO dao = new StudentDAO(); + + // 查询所有学生 + List students = dao.getAllStudents(); + System.out.println("所有学生信息："); + for (Student student : students) { + System.out.printf("编号：%d，姓名：%s，性别：%s\n", student.getId(), student.getName(), student.getGender()); + } + + // 添加学生 + Student newStudent = new Student(); + newStudent.setId(4); + newStudent.setName("傻狗"); + newStudent.setSex("男"); + dao.addStudent(newStudent); + System.out.println("添加学生成功"); + + // 修改学生信息 + Student updateStudent = new Student(); + updateStudent.setId(4); + updateStudent.setName("大傻狗"); + updateStudent.setSex("男"); + dao.updateStudent(updateStudent); + System.out.println("修改学生信息成功"); + + // 删除学生 + dao.deleteStudent(2); + System.out.println("删除学生成功"); + } +} +``` + -- Gitee