databaseoperation.java~1~

简单的代码

package xue;
import java.sql.*;
import java.awt.*;


class DataBaseOperation {
    private Connection connection;
     public DataBaseOperation(String driver,String url) throws ClassNotFoundException,SQLException{
        this.connection=null;
        Class.forName(driver);
        this.connection=DriverManager.getConnection(url);
    }
    public void finalize() throws SQLException{
        this.connection.close();
    }
    /*public String getDBAbout() throws SQLException{
        String message="";
        DatabaseMetaData dbmd=this.connection.getMetaData();
        message="JDBC驱动程序:"+dbmd.getDriverName()+" "+dbmd.getDriverVersion()+"\r\n"+
                "JDBC URL:"+dbmd.getURL()+"\r\n"+"数据库:"+dbmd.getDatabaseProductName()+"\r\n"+
                "数据库版本:"+dbmd.getDatabaseProductVersion()+"\r\n"+"用户名:"+dbmd.getUserName()+"\r\n";
        return message;
    }*/
    public int dataUpdate(String sql) throws SQLException{
        Statement statement=this.connection.createStatement();
        int result=statement.executeUpdate(sql);
        statement.close();
        return result;
    }
    public void select(String sql) throws SQLException{
        Statement statement=this.connection.createStatement();
        ResultSet resultset=statement.executeQuery(sql);
        ResultSetMetaData rsmd=resultset.getMetaData();
        int columnCount=rsmd.getColumnCount();
        for(int j=1;j<=columnCount;j++)
           {
 System.out.print(rsmd.getColumnLabel(j)+"  ");}
        System.out.println();
         int i=0;
        while(resultset.next()){
            for(int j=1;j<=columnCount;j++)
{    st[i]=resultset.getString(j)+"  ";

                System.out.print(resultset.getString(j)+"  ");}
            i++;
            System.out.println();
             }
             resultset.close();
             statement.close();
    }
    public int selectCount(String sql)throws SQLException{
        Statement statement=this.connection.createStatement();
        ResultSet resultset=statement.executeQuery(sql);
        resultset.next();
        int count=resultset.getInt(1);
        resultset.close();
        statement.close();
        return count;
    }
    public String[] selectDistinct(String table,String column)throws SQLException{
        String[] results=null;
        if(table!=null&&table!=""){
            String sql="SELECT DISTINCT"+"FROM"+table+"ORDER BY"+column;
            Statement statement=this.connection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
            ResultSet resultset=statement.executeQuery(sql);
            if(resultset!=null){
                int rowCount=0;
                while(resultset.next())
                    rowCount++;
                results=new String[rowCount+1];
                results[0]="分类查询";
                resultset.beforeFirst();
                int i=1;
                while(resultset.next()){
                    results[i]=resultset.getString(1);
                    i++;
                    }
        }
        resultset.close();
        statement.close();
        }
        else throw new SQLException("表名不能为空");
        return results;
    }
}