userdao.java

struts入门教程

/*
 * Created on 2009-4-13
 *
 * TODO To change the template for this generated file go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
package cn.edu.zucc.struts.app01;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;





/**
 * @author Administrator
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class UserDAO {
	private Connection conn = null;
    private Statement st = null;
    public UserDAO() {
        try {
            Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
            conn = DriverManager
                    .getConnection(
                            "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=j2ee_news",
                            "sa", "jiangshan");
            st = conn.createStatement();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
    public synchronized void release() {
        if (st != null) {
            try {
                st.close();
            } catch (Exception e) {
            }
        }

        if (conn != null) {
            try {
                conn.close();
            } catch (Exception e) {
            }
        }

    }
    public synchronized List loadAllUsers() throws Exception{
        List result = new ArrayList();
        try {
            ResultSet rs = st.executeQuery("select * from tb_users");
            while (rs.next()) {
            	ActfrmLogin user=new ActfrmLogin();
                user.setPwd(rs.getString("pwd"));
                user.setUserid(rs.getString("userid"));             
                result.add(user);
            }
        } catch (Exception ex) {
            ex.printStackTrace();
            throw new Exception("数据库查询错误");
        }
        return result;
    }
    public synchronized ActfrmLogin readUser(String userid) throws Exception{
    	ActfrmLogin result=null;
        try {
            ResultSet rs = st.executeQuery("select * from tb_users where userid='"+userid+"'");
            if (rs.next()) {
                result=new ActfrmLogin();
                result.setPwd(rs.getString("pwd"));
                result.setUserid(rs.getString("userid"));
                
            }
        } catch (Exception ex) {
            ex.printStackTrace();
            throw new Exception("数据库查询错误");
        }
        
        return result;
        
    }
    
}