jdbc

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jdbc连接数据库

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jdbc连接数据库步骤：

1选择数据库类型和导入JAR包；2加载驱动(Class.forName("com.mysql.jdbc.Driver"))；3获取数据库连接(DriverManager.getConnection(url, user, password);)；

4创建Statement对象；5调用statement执行相应的SQL；6关闭数据库连接。

-----------------------------------------------------------------------bd连接-------------------------------------------------------------------------------------

public class Dbhelper {
   String url="jdbc:mysql://localhost:3306/test";
   String password="pwd123qwer";
   String user ="root";
   private static Connection con=null;
   public ResultSet rs = null;
   public PreparedStatement pst = null;
   public Dbhelper(String sql){
       try {
           Class.forName("com.mysql.jdbc.Driver");
           con = DriverManager.getConnection(url, user, password);
       } catch (ClassNotFoundException e) {
           e.printStackTrace();
       } catch (SQLException e) {
           e.printStackTrace();
       }
   }
   public void close(){
       try {
           this.con.close();
           this.pst.close();
       } catch (SQLException e) {
           e.printStackTrace();
       }
   }
}

--------------------------------------------------------------------------------------测试连接--------------------------------------------------------------------------------------------------------

public class TestDB {
   static String sql=null;
   static Dbhelper db = null;
   static ResultSet rs = null;
   public static void main(String[] args) {
       sql="select * from customer";
       db = new Dbhelper(sql);
       try {
           rs = db.pst.executeQuery();
           JSONObject object = new JSONObject();
           object.put("rs", rs);
           System.out.println(object.get(rs).toString());
       } catch (SQLException e) {
           e.printStackTrace();
       }
   }
}

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