package?com.db;

import?java.sql.*;

public?class?DBManager?{

????//?數據庫連接常量
????public?static?final?String?DRIVER?=?“com.mysql.jdbc.Driver“;
????public?static?final?String?USER?=?“root“;
????public?static?final?String?PASS?=?“123456“;
????public?static?final?String?URL?=?“jdbc:mysql://119.29.148.222:3306/stumanager“;

????//?靜態成員，支持單態模式
????private?static?DBManager?per?=?null;
????private?Connection?conn?=?null;
????private?Statement?stmt?=?null;

????//?單態模式-懶漢模式
????private?DBManager（）?{
????}

????public?static?DBManager?createInstance（）?{
????????if?（per?==?null）?{
????????????per?=?new?DBManager（）;
????????????per.initDB（）;
????????}
????????return?per;
????}

????//?加載驅動
????public?void?initDB（）?{
????????try?{
????????????Class.forName（“com.mysql.jdbc.Driver“）;
????????}?catch?（Exception?e）?{
????????????e.printStackTrace（）;
????????}
????}

????//?連接數據庫，獲取句柄+對象
????public?void?connectDB（）?{
????????System.out.println（“Connecting?to?database...“）;
????????try?{
????????????conn?=?DriverManager.getConnection（URL?USER?PASS）;
????????????stmt?=?conn.createStatement（）;
????????}?catch?（SQLException?e）?{
????????????e.printStackTrace（）;
????????}
????????System.out.println（“SqlManager:Connect?to?database?successful.“）;
????}

????//?關閉數據庫?關閉對象，釋放句柄
????public?void?closeDB（）?{
????????System.out.println（“Close?connection?to?database..“）;
????????try?{
????????????stmt.close（）;
????????????conn.close（）;
????????}?catch?（SQLException?e）?{
????????????e.printStackTrace（）;
????????}
????????System.out.println（“Close?connection?successful“）;
????}

????//?查詢
????public?ResultSet?executeQuery（String?sql）?{
????????ResultSet?rs?=?null;
????????try?{
????????????rs?=?stmt.executeQuery（sql）;
????????}?catch?（SQLException?e）?{
????????????e.printStackTrace（）;
????????}
????????return?rs;
????}

????//?增添/刪除/修改
????public?int?executeUpdate（String?sql）?{
????????int?ret?=?0;
????????try?{
????????????ret?=?stmt.executeUpdate（sql）;
????????}?catch?（SQLException?e）?{
????????????e.printStackTrace（）;
????????}
????????return?ret;
????}
}

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件????????475??2017-04-28?14:29??StudentManage\.classpath

?????文件????????849??2017-04-28?14:29??StudentManage\.project

?????文件???????3768??2017-06-01?14:11??StudentManage\AndroidManifest.xml

?????文件???????3768??2018-01-15?21:14??StudentManage\bin\AndroidManifest.xml

?????文件???????2737??2018-01-15?21:15??StudentManage\bin\classes\com\custom\arrary.class

?????文件???????1576??2018-01-15?21:15??StudentManage\bin\classes\com\custom\CreateUserDialog.class

?????文件???????1245??2018-01-15?21:15??StudentManage\bin\classes\com\custom\SegmentView$1.class

?????文件???????1245??2018-01-15?21:15??StudentManage\bin\classes\com\custom\SegmentView$2.class

?????文件????????284??2018-01-15?21:15??StudentManage\bin\classes\com\custom\SegmentView$onSegmentViewClickListener.class

?????文件???????4277??2018-01-15?21:15??StudentManage\bin\classes\com\custom\SegmentView.class

?????文件????????359??2018-02-16?22:09??StudentManage\bin\classes\com\example\studentmanage\BuildConfig.class

?????文件????????361??2018-02-16?22:09??StudentManage\bin\classes\com\example\studentmanage\R$attr.class

?????文件????????482??2018-02-16?22:09??StudentManage\bin\classes\com\example\studentmanage\R$dimen.class

?????文件???????1097??2018-02-16?22:09??StudentManage\bin\classes\com\example\studentmanage\R$drawable.class

?????文件???????2039??2018-02-16?22:09??StudentManage\bin\classes\com\example\studentmanage\R$id.class

?????文件????????732??2018-02-16?22:09??StudentManage\bin\classes\com\example\studentmanage\R$layout.class

?????文件????????409??2018-02-16?22:09??StudentManage\bin\classes\com\example\studentmanage\R$menu.class

?????文件????????493??2018-02-16?22:09??StudentManage\bin\classes\com\example\studentmanage\R$string.class

?????文件????????483??2018-02-16?22:09??StudentManage\bin\classes\com\example\studentmanage\R$style.class

?????文件????????743??2018-02-16?22:09??StudentManage\bin\classes\com\example\studentmanage\R.class

?????文件????????819??2018-01-15?21:15??StudentManage\bin\classes\com\kcat\studentmanage\Add_course$1.class

?????文件???????1616??2018-01-15?21:15??StudentManage\bin\classes\com\kcat\studentmanage\Add_course$10.class

?????文件???????1908??2018-01-15?21:15??StudentManage\bin\classes\com\kcat\studentmanage\Add_course$11.class

?????文件????????870??2018-01-15?21:15??StudentManage\bin\classes\com\kcat\studentmanage\Add_course$12.class

?????文件???????1914??2018-01-15?21:15??StudentManage\bin\classes\com\kcat\studentmanage\Add_course$13.class

?????文件????????870??2018-01-15?21:15??StudentManage\bin\classes\com\kcat\studentmanage\Add_course$14.class

?????文件???????1713??2018-01-15?21:15??StudentManage\bin\classes\com\kcat\studentmanage\Add_course$15.class

?????文件???????1537??2018-01-15?21:15??StudentManage\bin\classes\com\kcat\studentmanage\Add_course$16.class

?????文件???????1866??2018-01-15?21:15??StudentManage\bin\classes\com\kcat\studentmanage\Add_course$17.class

?????文件????????870??2018-01-15?21:15??StudentManage\bin\classes\com\kcat\studentmanage\Add_course$18.class

............此處省略314個文件信息