database.java

java编写的与SQL数据连接的好例子~~功能很完善,可以做实训直接交

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package stuMS;
import java.sql.*;
/**
 *
 * @author Administrator
 */
public class Database {
    private Statement stmt=null;
    ResultSet results=null;
    private Connection connect=null;
    String sql;
    String strurl="jdbc:microsoft:sqlserver://localhost:1433;User=sa;Password=sa;DatabaseName=scmanage";
    public Database(){
    }
    public void OpenConn()throws Exception{
        try{
            Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
            connect=DriverManager.getConnection(strurl);
        }
        catch(Exception e){ 
            System.err.println("OpenConn:"+e.getMessage());
        }
    }
    /**
     * 数据库查询
     * @param sql
     * @return
     */
    public ResultSet executeQuery(String sql){ 
        stmt = null;
        results=null;
        this.sql = sql;
        try{
            stmt=connect.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
            results=stmt.executeQuery(sql);
        }
        catch(SQLException e){
            System.err.println("executeQuery:"+e.getMessage());
        }
        return results;
    }
    /**
     * 更新数据库
     * @param sql
     */
    public void executeUpdate(String sql){
        stmt=null;
        results=null;
        this.sql = sql;
        try{
            stmt=connect.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
            stmt.executeUpdate(sql);
            connect.commit();//commit是提交一个事务，如果发生了错误，可以在finally里面rollback，rollback可以把之前提交的操作撤销。
        }catch(SQLException e){
            System.err.println("executeUpdate:"+e.getMessage());
        }
    }
    public void closeStmt(){
        try{
            stmt.close();
        }
        catch(SQLException e){
            System.err.println("closeStmt:"+e.getMessage());
        }
    }
    /**
     * 关闭数据库连接
     */
    public void closeConn(){
        try{
            connect.close();
        }
        catch(SQLException ex){
            System.err.println("aq.closeConn:"+ex.getMessage());
        }
    }
}