基于Spring5核心原理的30个类手写实战设计源码

public void save(Student stu){ String sql="INSERT INTO t_student(name,age) VALUES(?,?)"; Connection conn=null; Statement st=null; try{ // 1. 加载注册驱动 Class.forName("com.mysql.jdbc.Driver"); // 2. 获取数据库连接 conn=DriverManager.getConnection("jdbc:mysql:///jdbcdemo","root","root"); // 3. 创建语句对象 PreparedStatement ps=conn.prepareStatement(sql); ps.setObject(1,stu.getName()); ps.setObject(2,stu.getAge()); // 4. 执行SQL语句 ps.executeUpdate(); // 5. 释放资源 }catch(Exception e){ e.printStackTrace(); }finally{ try{ if(st!=null) st.close(); }catch(SQLException e){ e.printStackTrace(); }finally{ try{ if(conn!=null) conn.close(); }catch(SQLException e){ e.printStackTrace(); } } } } // 删除学生信息 public void delete(Long id){ String sql="DELETE FROM t_student WHERE id=?"; Connection conn=null; Statement st=null; try{ // 1. 加载注册驱动 Class.forName("com.mysql.jdbc.Driver"); // 2. 获取数据库连接 conn=DriverManager.getConnection("jdbc:mysql:///jdbcdemo","root","root"); // 3. 创建语句对象 PreparedStatement ps=conn.prepareStatement(sql); ps.setObject(1,id); // 4. 执行SQL语句 ps.executeUpdate(); // 5. 释放资源 }catch(Exception e){ e.printStackTrace(); }finally{ try{ if(st!=null) st.close(); }catch(SQLException e){ e.printStackTrace(); }finally{ try{ if(conn!=null) conn.close(); }catch(SQLException e){ e.printStackTrace(); } } } } // 修改学生信息 public void update(Student stu){ String sql="UPDATE t_student SET name=?,age=? WHERE id=?"; Connection conn=null; Statement st=null; try{ // 1. 加载注册驱动 Class.forName("com.mysql.jdbc.Driver"); // 2. 获取数据库连接 conn=DriverManager.getConnection("jdbc:mysql:///jdbcdemo","root","root"); // 3. 创建语句对象 PreparedStatement ps=conn.prepareStatement(sql); ps.setObject(1,stu.getName()); ps.setObject(2,stu.getAge()); ps.setObject(3,stu.getId()); // 4. 执行SQL语句 ps.executeUpdate(); // 5. 释放资源 }catch(Exception e){ e.printStackTrace(); }finally{ try{ if(st!=null) st.close(); }catch(SQLException e){ e.printStackTrace(); }finally{ try{ if(conn!=null) conn.close(); }catch(SQLException e){ e.printStackTrace(); } } } } //工具类 public class JdbcUtil { private JdbcUtil() { } static { // 1. 加载注册驱动 try { Class.forName("com.mysql.jdbc.Driver"); } catch (Exception e) { e.printStackTrace(); } } public static Connection getConnection() { try { // 2. 获取数据库连接 return DriverManager.getConnection("jdbc:mysql:///jdbcdemo", "root", "root"); } catch (Exception e) { e.printStackTrace(); } return null; } //释放资源 public static void close(ResultSet rs, Statement st, Connection conn) { try { if (rs != null) rs.close(); } catch (SQLException e) { e.printStackTrace(); } finally { try { if (st != null) st.close(); } catch (SQLException e) { e.printStackTrace(); } finally { try { if (conn != null) conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } } } // 增加学生信息 public void save(Student stu) { String sql = "INSERT INTO t_student(name,age) VALUES(?,?)"; Connection conn = null; PreparedStatement ps=null; try { conn = JDBCUtil.getConnection(); // 3. 创建语句对象 ps = conn.prepareStatement(sql); ps.setObject(1, stu.getName()); ps.setObject(2, stu.getAge()); // 4. 执行SQL语句 ps.executeUpdate(); // 5. 释放资源 } catch (Exception e) { e.printStackTrace(); } finally { JDBCUtil.close(null, ps, conn); } } // 删除学生信息 public void delete(Long id) { String sql = "DELETE FROM t_student WHERE id=?"; Connection conn = null; PreparedStatement ps = null; try { conn=JDBCUtil.getConnection(); // 3. 创建语句对象 ps = conn.prepareStatement(sql); ps.setObject(1, id); // 4. 执行SQL语句 ps.executeUpdate(); // 5. 释放资源 } catch (Exception e) { e.printStackTrace(); } finally { JDBCUtil.close(null, ps, conn); } } // 修改学生信息 public void update(Student stu) { String sql = "UPDATE t_student SET name=?,age=? WHERE id=?"; Connection conn = null; PreparedStatement ps = null; try { conn=JDBCUtil.getConnection(); // 3. 创建语句对象 ps = conn.prepareStatement(sql); ps.setObject(1, stu.getName()); ps.setObject(2, stu.getAge()); ps.setObject(3, stu.getId()); // 4. 执行SQL语句 ps.executeUpdate(); // 5. 释放资源 } catch (Exception e) { e.printStackTrace(); } finally { JDBCUtil.close(null, ps, conn); } } public Student get(Long id) { String sql = "SELECT * FROM t_student WHERE id=?"; Connection conn = null; Statement st = null; ResultSet rs = null; PreparedStatement ps=null; try { conn = JDBCUtil.getConnection(); // 3. 创建语句对象 ps = conn.prepareStatement(sql); ps.setObject(1, id); // 4. 执行SQL语句 rs = ps.executeQuery(); if (rs.next()) { String name = rs.getString("name"); int age = rs.getInt("age"); Student stu = new Student(id, name, age); return stu; } // 5. 释放资源 } catch (Exception e) { e.printStackTrace(); } finally { JDBCUtil.close(rs, ps, conn); } return null; } public List<Student> list() { List<Student> list = new ArrayList<>(); String sql = "SELECT * FROM t_student "; Connection conn = null; Statement st = null; ResultSet rs = null; PreparedStatement ps=null; try { conn=JDBCUtil.getConnection(); // 3. 创建语句对象 ps = conn.prepareStatement(sql); // 4. 执行SQL语句 rs = ps.executeQuery(); while (rs.next()) { long id = rs.getLong("id"); String name = rs.getString("name"); int age = rs.getInt("age"); Student stu = new Student(id, name, age); list.add(stu); } // 5. 释放资源 } catch (Exception e) { e.printStackTrace(); } finally { JDBCUtil.close(rs, ps, conn); } return list; } static { // 1. 加载注册驱动 try { ClassLoader loader = Thread.currentThread