dbconnbean.java

实现基本的书店管理

// FrontEnd Plus for JAD
// DeCompiled : DbConnBean.class

package conndb;

import java.io.PrintStream;
import java.io.UnsupportedEncodingException;
import java.sql.*;

public class DbConnBean
{

    private static Connection conn;
    private Statement stmt;
    private ResultSet rs;

    public DbConnBean()
    {
    }

    public void init(Connection conn)
    {
        try
        {
            stmt = conn.createStatement();
        }
        catch(Exception e)
        {
            System.out.println((new StringBuilder("init:")).append(e.getMessage()).toString());
        }
    }

    public void close()
    {
        try
        {
            if(rs != null)
                rs.close();
        }
        catch(Exception e)
        {
            System.out.println((new StringBuilder("rs.close():")).append(e.getMessage()).toString());
        }
        try
        {
            if(stmt != null)
                stmt.close();
        }
        catch(Exception e)
        {
            System.out.println((new StringBuilder("stmt.close():")).append(e.getMessage()).toString());
        }
        try
        {
            if(conn != null)
                conn.close();
        }
        catch(Exception e)
        {
            System.out.println((new StringBuilder("conn.close():")).append(e.getMessage()).toString());
        }
    }

    public int select(String sql)
    {
        int k = -10;
        init(getConn());
        try
        {
            k = 0;
            rs = stmt.executeQuery(sql);
            if(rs.next())
                k++;
        }
        catch(Exception e)
        {
            k = -1;
            System.out.println((new StringBuilder("select():")).append(e.getMessage()).toString());
            close();
        }
        close();
        return k;
    } 

    public int update(String sql)
    {
        int k = -10;
        init(getConn());
        try
        {
            k = 0;
            k = stmt.executeUpdate(sql);
        }
        catch(Exception e)
        {
            k = -1;
            System.out.println((new StringBuilder("update():")).append(e.getMessage()).toString());
        }
        close();
        return k;
    }

    public static synchronized Connection getConn()
    {
        try
        {
            Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
            String URL="jdbc:microsoft:sqlserver://127.0.0.1:1433;DatabaseName=booklib";
            conn = DriverManager.getConnection(URL, "sa", "sa");
            System.out.println("连接建立！");
        }
        catch(Exception e)
        {
          System.out.print(e);
        }
        return conn;
    }

    public String chStr(String str) throws UnsupportedEncodingException 
    {
        String temp2;
        byte temp[] = str.getBytes("ISO8859-1");
        temp2 = new String(temp);
        return temp2;
    }

    public ResultSet query(String sql)
    {
        try
        {
            rs = stmt.executeQuery(sql);
        }
        catch(Exception e)
        {
            e.getMessage();
        }
        return rs;
    }
}