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编写DBUtil及测试

發(fā)布時間:2023/12/9 编程问答 42 豆豆
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DBUtil頁面

package lesson1101.demo002;import com.mysql.jdbc.Connection; import com.mysql.jdbc.PreparedStatement; import com.mysql.jdbc.ResultSetImpl;import java.sql.DriverManager; import java.sql.SQLException;public class DBUtil {private static String driverName="com.mysql.jdbc.Driver";private static String url="jdbc:mysql://127.0.0.1:3306/school?useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8&useSSL=false";private static String user="root";private static String pwd="123456";private static PreparedStatement ps;private static Connection conn;private static ResultSetImpl rs;//啟動資源public static void getConn(){try {Class.forName(driverName);conn = (Connection) DriverManager.getConnection(url,user,pwd);} catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException throwables) {throwables.printStackTrace();}}//關(guān)閉資源public void close(){try {//進行判斷if (rs!=null){rs.close();}if (ps!=null){ps.close();}if (conn!=null){conn.close();}} catch (SQLException e) {e.printStackTrace();}}//查詢public ResultSetImpl query(String sql ,Object...obj){//啟動資源getConn();try {//執(zhí)行SQL語句ps = (PreparedStatement) conn.prepareStatement(sql);for (int i = 0; i < obj.length; i++) {ps.setObject(i-1,obj[i]);}rs = (ResultSetImpl) ps.executeQuery();} catch (SQLException e) {e.printStackTrace();}//返回結(jié)果集return rs;}//添加,刪除,修改public int update(String sql ,Object...obj){//啟動資源getConn();int a = 0;try {//執(zhí)行SQL語句ps = (PreparedStatement) conn.prepareStatement(sql);for (int i = 0; i < obj.length; i++) {ps.setObject(i+1,obj[i]);}//a被改變,成功,未改變則失敗a = ps.executeUpdate();} catch (SQLException e) {e.printStackTrace();}//返回areturn a;}}

查詢測試

package lesson1101.demo002;import com.mysql.jdbc.ResultSetImpl;import java.sql.SQLException;public class Test001 {public static void main(String[] args) {//查DBUtil db = new DBUtil();ResultSetImpl rs = db.query("select * from studentinfo");try {while (rs.next()){int stuid = rs.getInt("stuid");String sname = rs.getString("sname");int sage = rs.getInt("sage");String ssex = rs.getString("ssex");int cid = rs.getInt("cid");System.out.println(stuid+" "+sname+" "+sage+" "+ssex+" "+cid);}} catch (SQLException throwables) {throwables.printStackTrace();} finally {db.close();}} }

查詢測試圖

?添加測試

package lesson1101.demo002;public class Test002 {public static void main(String[] args) {//插入數(shù)據(jù)DBUtil db = new DBUtil();int a = db.update("insert into studentinfo values(null,'趙瑞',25,'男',1)");if (a!=0){System.out.println("插入成功");}else {System.out.println("插入失敗");}}}

?修改測試

package lesson1101.demo002;public class Test004 {public static void main(String[] args) {//修改數(shù)據(jù)DBUtil db = new DBUtil();int a = db.update("update studentinfo set ssex='女' where sname='趙瑞'");if (a != 0) {System.out.println("修改成功");} else {System.out.println("修改失敗");}} }

刪除測試

package lesson1101.demo002;public class Test003 {public static void main(String[] args) {//刪除數(shù)據(jù)DBUtil db = new DBUtil();int a = db.update("delete from studentinfo where sname='趙瑞'");if (a!=0){System.out.println("刪除成功");}else {System.out.println("刪除失敗");}} }

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