import javax.sql.rowset.CachedRowSet;
import javax.sql.rowset.RowSetFactory;
import javax.sql.rowset.RowSetProvider;
import java.io.FileInputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Properties;

public class CachedRowSetTest {
//    常規操作，不解釋~~
    private static String driver;
    private static String url;
    private static String user;
    private static String pass;

    public void initParam(String fileName) throws Exception{
        Properties prop =  new Properties();
        prop.load(new FileInputStream(fileName));
        driver = prop.getProperty("driver");
        url  = prop.getProperty("url");
        user = prop.getProperty("user");
        pass = prop.getProperty("pass");
    }

    public CachedRowSet query(String sql) throws  Exception{
        Class.forName(driver);
        Connection conn = DriverManager.getConnection(url, user, pass);
        Statement stmtm = conn.createStatement();
        ResultSet rs = stmtm.executeQuery(sql);

        RowSetFactory factory = RowSetProvider.newFactory();
//        建立RowSetFactory物件

        CachedRowSet cachedRowSet = factory.createCachedRowSet();
//        通過RowSetFactory物件創捷CacheRowSet物件

        cachedRowSet.populate(rs);
//        將查詢的結果集封裝到CachedRowSet中

//        關閉連線
        rs.close();
        stmtm.close();
        conn.close();

        return cachedRowSet;
//        將封裝有結果集的CachedRowSet返回
    }
    public static void main(String args[]) throws  Exception{
        CachedRowSetTest ct = new CachedRowSetTest();
        ct.initParam("mysql.ini");
        CachedRowSet rs = ct.query("select * from students");
        rs.afterLast();

//        對離線RowSet進行一些處理
        while (rs.previous()){
            System.out.println(rs.getString(1) + "\t" + rs.getString(2));

            if(rs.getString("Sname").equals("Smith")){
                rs.updateString("Sno", "S4");
                rs.updateRow();
            }
        }
//        重新開啟資料庫連結，並且將修改過的結果集同步到資料庫中
        Connection conn = DriverManager.getConnection(url,user,pass);
        conn.setAutoCommit(false);
        rs.acceptChanges(conn);
    }
}
//執行程式，看到以下輸出結果
//        S3	Tom
//        S2	Marry
//        S0	Smith