使用軟件：mysql、eclipse
鏈接步驟：
1.注冊驅動
2.創建一個連接對象
3.寫sql語句
4.執行sql語句並返回一個結果或者結果集
5.關閉鏈接（一般就是connection、statement、setresult）這三個連接對象，關閉順序一般是（setresult ---> statement --> setresult ）
一、直接連接方法：（這種方法就是講sql語句和結果所有的步驟寫在一起） 不建議使用該方法
1 public static void main(String[] args) { 2 String url = "jdbc:mysql://localhost:3306/students"; 3 String user = "root"; 4 String password = "admin"; 5 Connection conn = null; 6 Statement st = null; 7 8 try { 9 // 1. 注冊驅動 10 Class.forName("com.mysql.jdbc.Driver"); 11 // 2. 創建一個鏈接對象 12 conn = DriverManager.getConnection(url,user,password); 13 // 3. 創建一個sql語句的發送命令對象 14 String sql = "insert into student values('2001','Tom','20','7000')"; 15 st= conn.createStatement(); 16 // 4. 執行sql語句，拿到查詢的結果集對象 17 st.executeQuery(sql);20 } catch (Exception e) { 21 e.printStackTrace(); 22 }finally { 23 // 5. 關閉鏈接 ，命令對象 ，結果集 24 if(st != null) { 25 try { 26 st.close(); 27 } catch (Exception e) { 28 e.printStackTrace(); 29 } 30 } 31 if(conn != null) { 32 try { 33 conn.close(); 34 } catch (Exception e) { 35 e.printStackTrace(); 36 } 37 } 38 }
二、建立工具類方法，將必要的幾步寫一個類，使用的時候直接調用（建議使用）
1.注冊驅動、創建連接對象、關閉資源 這三部一般可以寫一個類，由於寫sql語句和執行sql語句的結果不一致，所以可以將其在用到的時候在寫
2.一般寫工具類都是寫成靜態方法，以方便調用
//這是工具類：
import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; public class JdbcUtils { private static String driverName = "com.mysql.jdbc.Driver"; private static String url = "jdbc:mysql://localhost:3306/student_achievement_system"; private static String user = "root"; private static String password = "admin"; /** * 鏈接數據庫 */ static { try { Class.forName(JdbcUtils.driverName); } catch (Exception e) { e.printStackTrace(); } } /** * 獲取鏈接對象connection * @return */ public static Connection getConnection() { try { return DriverManager.getConnection(JdbcUtils.url, JdbcUtils.user, JdbcUtils.password); } catch (Exception e) { e.printStackTrace(); } return null; } /** * 關閉資源 * @param conn * @param st * @param rs */ public static void close(Connection conn,Statement st,ResultSet rs) { if(rs != null) { try { rs.close(); } catch (Exception e) { e.printStackTrace(); } } if(st != null) { try { st.close(); } catch (Exception e) { e.printStackTrace(); } } if(conn != null) { try { conn.close(); } catch (Exception e) { e.printStackTrace(); } } } }
//這是對數據庫的基本操作類
// 增加、刪除、更新、查找一條、查找所有的方法
public class StudentsDaoImpl implements IStudentsDao { //增加 @Override public int save(Students student) { Connection conn = null; PreparedStatement ps = null; try { conn = JdbcUtils.getConnection(); String sql = "insert into students values(?,?,?,?,?,?)"; ps = conn.prepareStatement(sql); ps.setInt(1, student.getStudentId()); ps.setString(2, student.getStudentName()); ps.setString(3, student.getSex()); ps.setString(4, student.getPhoneNo()); ps.setString(5, student.getAddress()); ps.setDate(6, (Date) student.getBirthday()); int row = ps.executeUpdate(); return row; } catch (Exception e) { e.printStackTrace(); }finally { JdbcUtils.close(conn, ps, null); } return 0; } //刪除 @Override public int delete(int studentId) { Connection conn = null; PreparedStatement ps = null; try { conn = JdbcUtils.getConnection(); String sql = "delete from students where studentId=?"; ps = conn.prepareStatement(sql); ps.setInt(1, studentId); int row = ps.executeUpdate(); return row; } catch (Exception e) { e.printStackTrace(); }finally { JdbcUtils.close(conn, ps, null); } return 0; } //更新 @Override public int update(int studentId, Students student) { Connection conn = null; PreparedStatement ps = null; try { conn = JdbcUtils.getConnection(); String sql = "update students set studentName=?,sex=?,phoneNo=?,address=?,birthday=? where studentId=?"; ps = conn.prepareStatement(sql); ps.setString(1, student.getStudentName()); ps.setString(2, student.getSex()); ps.setString(3, student.getPhoneNo()); ps.setString(4, student.getAddress()); ps.setDate(5, ((Date) student.getBirthday())); ps.setInt(6, studentId); int row = ps.executeUpdate(); return row; } catch (Exception e) { e.printStackTrace(); }finally { JdbcUtils.close(conn, ps, null); } return 0; } //查找一條數據 @Override public Students getByStudentId(int studentId) { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; try { conn = JdbcUtils.getConnection(); String sql = "select * from students where studentId=?"; ps = conn.prepareStatement(sql); ps.setInt(1, studentId); rs = ps.executeQuery(); if(rs.next()) { Students student = new Students(); student.setStudentId(rs.getInt("studentId")); student.setStudentName(rs.getString("studentName")); student.setSex(rs.getString("sex")); student.setPhoneNo(rs.getString("phoneNo")); student.setAddress(rs.getString("address")); student.setBirthday(rs.getDate("birthday")); return student; } } catch (Exception e) { e.printStackTrace(); }finally { JdbcUtils.close(conn, ps, rs); } return null; } //查找所有數據 @Override public List<Students> getAll() { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; try { conn = JdbcUtils.getConnection(); String sql = "select * from students"; ps = conn.prepareStatement(sql); rs = ps.executeQuery(); List<Students> studentsList = new ArrayList<>(); while(rs.next()) { Students student = new Students(); student.setStudentId(rs.getInt("studentId")); student.setStudentName(rs.getString("studentName")); student.setSex(rs.getString("sex")); student.setPhoneNo(rs.getString("phoneNo")); student.setAddress(rs.getString("address")); student.setBirthday(rs.getDate("birthday")); studentsList.add(student); } return studentsList; } catch (Exception e) { e.printStackTrace(); }finally { JdbcUtils.close(conn, ps, rs); } return null; }
}