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java flex �l�合 — Thu, 28 Feb 2008 07:27:00 GMT

Facade模式的定�?/strong>: 为子�pȝ��中的一�l�接口提供一个一致的界面.Facade一个典型应用就是数据库JDBC的应�?如下例对数据库的操作:
说明�Q?/strong>�q�是在网上的一��文章中看到的列子，上面没有写全�Q�我在这里补上了�Q�没有用到接口�?br />
package com.pattern.structural.facade;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/*
* 外观模式的主要用途就是�ؓ子系�l�的复杂处理�q�程提供方便的调用方法，
* 使得子系�l�更加容易被使用�?br /> * Facade对象通常属于Singleton模式�?br /> */
public class Mysql {

    private static Connection conn=null;
    private static PreparedStatement prep=null;

    public Mysql(String sql) {
        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/test","root","");
            prep = conn.prepareStatement(sql);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void setString(int index, String parString) {
        try {
            prep.setString(index, parString);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public ResultSet executeQuery() {
        try {
            return prep.executeQuery();
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        }
    }

    public void close() {
        try {
            conn.close();
            prep.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

package com.pattern.structural.facade;

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

public class DBCompare {

    public void getResultSet(String sql) {
//        String sql = "SELECT * FROM bulletin WHERE id = ?";
        Mysql mysql = new Mysql(sql);
        try {
            mysql.setString(1, "4");
            ResultSet rset = mysql.executeQuery();
            while (rset.next()) {
                System.out.println(rset.getString("id"));
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            mysql.close();
            mysql = null;
        }
    }
}

package com.pattern.structural.facade;

import java.sql.ResultSet;

public class FacadeTest {

    public static void main(String[] args) {

        Mysql mysql = new Mysql("SELECT * FROM bulletin");
        try {
            ResultSet rset = mysql.executeQuery();
            while (rset.next()) {
                System.out.println(rset.getString("id"));
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            mysql.close();
            mysql = null;
        }

    }

}

java flex �l�合 2008-02-28 15:27 发表评论

设计模式之Command——电视篇

java flex �l�合 — Wed, 27 Feb 2008 01:21:00 GMT

大家都知�?/span>电视遥控器节目面板（ProgramPan�Q�是��p��目按钮组成，通过选择相应的节目按钮，��可以切换到相应的节目屏道�?/span>

下来让我们看看如何实现通过遥控器按钮选择节目屏道的过�E�吧�?/font>

1、在�q�里�Q�先定义遥控器按钮（RemoteControlButton�Q�接口：

public interface RemoteControlButton {

public abstract void selectProgram(); //选择节目屏道

}

2、再定义遥控器按钮（RemoteControlButton�Q�接口的实现�c�：

A�Q�卡通节目按钮（CartonProgramButton�Q�类�Q?/span>

public class CartonProgramButton implements RemoteControlButton{

public void selectProgram() {

    System.out.println("选择了卡通屏道！");

}

}

B�Q�电视剧节目按钮�Q?/span>TvPlanProgramButton�Q�类�Q?/span>

public class TvPlanProgramButton implements RemoteControlButton {

public void selectProgram() {

    System.out.println("选择了电视剧屏道�Q?/span>");

}

}

C�Q��球节目按钮（FootProgramButton�Q�类�Q?/span>

public class FootProgramButton implements RemoteControlButton {

public void selectProgram() {

    System.out.println("选择了��球屏道！");

}

}

3、遥控器节目面板�Q?/span>ProgramPan�Q�类�Q�用来控制节目按钮，昄��节目

public class ProgramPan {

public static List programList() {

    List list = new ArrayList(); //节目屏道按钮列表

    list.add(new CartonProgramButton()); //卡通屏道按�?/span>

    list.add(new TvPlanProgramButton()); //电视剧屏道按�?/span>

    list.add(new FootProgramButton());   //��球屏道按钮

    return list;

}

}

4、编写测试类�Q?/span>

public class TestCommand {

public static void main(String[] args) {

    List list = ProgramPan.programList(); //获得节目屏道按钮

    for (Iterator it = list.iterator();it.hasNext();)

      ( (RemoteControlButton) it.next()).selectProgram(); //选择节目屏道中对应的节目

}

}

5、说明：

A�Q?/span>Command说白了就是通过选择一个个命��o�Q�然后执行相应动作�?/span>

B�Q?/span>Command是对行�ؓ�q�行��装的典型模式，在本例中通过遥控器节目面板（ProgramPan�Q�这个封装类来实现我们看电视节目的目的�?/span>

C�Q?/span>Command模式�?/span>Facade(外观)模式��g��比较�怼�。都是通过��装�c�L��q�行讉K��的。如何区分，对这�Ҏ��也比较疑惑�?/span>

java flex �l�合 2008-02-27 09:21 发表评论