dbconn.java

jsp开发常用信息管理系统适合初学者学习 新闻管理

package ch06;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class dbConn
{

    public dbConn()
        throws Exception
    {
        config = new config();
        DBurl = "jdbc:mysql://localhost:3306/" + config.DBname + "?user=" + config.DBuser + "&password=" + config.DBpwd;
        conn = null;
        rs = null;
        stmt = null;
        preStmt = null;
        try
        {
            Class.forName(config.DBdriver).newInstance();
        }
        catch(ClassNotFoundException _ex)
        {
            throw new Exception("\u627E\u4E0D\u5230\u9A71\u52A8\uFF01");
        }
    }

    public dbConn(int i)
        throws Exception
    {
        config = new config();
        DBurl = "jdbc:mysql://localhost:3306/" + config.DBname + "?user=" + config.DBuser + "&password=" + config.DBpwd;
        conn = null;
        rs = null;
        stmt = null;
        preStmt = null;
    }

    public void CloseConn()
        throws Exception
    {
        if(rs != null)
            rs.close();
        if(conn != null)
            conn.close();
        if(stmt != null)
            stmt.close();
        if(preStmt != null)
            preStmt.close();
    }

    public ResultSet ExeQuery()
        throws SQLException
    {
        try
        {
            rs = preStmt.executeQuery();
            conn.close();
            clearParameters();
        }
        catch(SQLException sqlexception)
        {
            System.err.println("aq.executeQuery:" + sqlexception.getMessage());
        }
        return rs;
    }

    public ResultSet ExeQuery(String s)
        throws SQLException
    {
        try
        {
            conn = DriverManager.getConnection(DBurl);
            stmt = conn.createStatement(1005, 1008);
            rs = stmt.executeQuery(s);
            conn.close();
        }
        catch(SQLException sqlexception)
        {
            System.err.println("aq.executeQuery:" + sqlexception.getMessage());
        }
        return rs;
    }

    public void ExeUpdate()
    {
        try
        {
            preStmt.executeUpdate();
            conn.close();
            clearParameters();
        }
        catch(SQLException sqlexception)
        {
            System.err.println("aq.executeUpdate:" + sqlexception.getMessage());
        }
    }

    public void ExeUpdate(String s)
    {
        try
        {
            conn = DriverManager.getConnection(DBurl);
            stmt = conn.createStatement();
            stmt.executeUpdate(s);
            conn.close();
        }
        catch(SQLException sqlexception)
        {
            System.err.println("aq.executeUpdate:" + sqlexception.getMessage());
        }
    }

    public void clearParameters()
        throws SQLException
    {
        preStmt.clearParameters();
        preStmt = null;
    }

    public void getPreparedStatement(String s)
        throws Exception
    {
        conn = DriverManager.getConnection(DBurl);
        preStmt = conn.prepareStatement(s);
    }

    public void setInt(int i, int j)
        throws SQLException
    {
        preStmt.setInt(i, j);
    }

    public void setString(int i, String s)
        throws SQLException
    {
        preStmt.setString(i, s);
    }

    config config;
    private String DBurl;
    private Connection conn;
    private ResultSet rs;
    private Statement stmt;
    private PreparedStatement preStmt;
}