设计模式

常用的设计模式

singleton           //单例模式
decorate            //装饰模式
adapter             //适配器模式
factory             //工厂模式
MVC                 //model - view - controller,模型(数据)-视图(界面)-控制器
Pool                //池化
Proxy               //代理

1、单例模式

/**
 * 单例模式
 * @author feigu
 *
 */
public class MonkeyKing {
    /**
     * 
     *懒汉式
     */
    private  static MonkeyKing instance;
    public static Object lock=new Object();
    //空参构造私有化
    private MonkeyKing(){};
    public static MonkeyKing getInstance(){
        if(instance==null){
            synchronized (lock) {
                if(instance==null){
                    instance=new MonkeyKing();
                }
                return instance;
            }
        }
        return instance;
        
    }
/**
 * 饿韩式
 */
    private  static MonkeyKing instance=new MonkeyKing();
    private MonkeyKing(){};
    public static MonkeyKing getInstance(){
        return instance;
    }
}

2、Builder模式（链式编程）

public class PhoneBuilder{
    public void test1(){
        Phone p=new Phone()
                .setBrand("三星")
                .setName("苹果")
                .setPrice(899)
                .setProductArea("江苏");
        System.out.println(p.getName());
        
    }
}

 class Phone {
    private String name;
    private String brand;
    private String productArea;
    private float price;
    public String getName() {
        return name;
    }
    public Phone setName(String name) {//有返回值注意
        this.name = name;
        return this;
    }
    public String getBrand() {
        return brand;
    }
    public Phone setBrand(String brand) {
        this.brand = brand;
        return this;
    }
    public String getProductArea() {
        return productArea;
    }
    public Phone setProductArea(String productArea) {
        this.productArea = productArea;
        return this;
    }
    public float getPrice() {
        return price;
    }
    public Phone setPrice(float price) {
        this.price = price;
        return this;
    }
    
}

3、适配器模式

public class TestWindow {
    public static void main(String[] args) {
        Window w = new Window();
        w.setWindowListener(new WindowAdapter(){
            public void onMax() {
                System.out.println("hello");
            }
        });
    }
}

//预实现
class WindowAdapter implements WindowListener{
    public void onMin() {
    }

    public void onMax() {
    }

    public void onClose() {
    }

    public void onResize() {
    }
}



//接口
public interface WindowListener {
    public void onMin();
    public void onMax();
    public void onClose();
    public void onResize();
}
//窗口类
/**
 * 窗口类 
 */
public class Window {
    
    private int size;
    private int location;

    public int getSize() {
        return size;
    }

    public void setSize(int size) {
        this.size = size;
    }

    public int getLocation() {
        return location;
    }

    public void setLocation(int location) {
        this.location = location;
    }
    
    public void setWindowListener(WindowListener l){
        l.onMax();
    }
}

4、工厂设计模式

/**
 * 工厂设计模式
 */
public class TestFactory {
    
    @Test
    public void test1(){
        TVSet tv = TVSetFactory.productTV();
        System.out.println(tv.getBrand());
    }
}

/**
 * 工厂设计模式 
 */
public class TVSetFactory {
    
    /**
     * 静态工厂方法
     */
    public static TVSet productTV(){
        TVSet tv = new TVSet();
        tv.setBrand("三星");
        tv.setName("xxx");
        tv.setPrice(500.f);
        return tv ;
    }
}


/**
 * TVSet
 */
public class TVSet {
    private String name;
    private String brand;
    private float price;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getBrand() {
        return brand;
    }

    public void setBrand(String brand) {
        this.brand = brand;
    }

    public float getPrice() {
        return price;
    }

    public void setPrice(float price) {
        this.price = price;
    }

}

5、装饰模式

public class TestDecorate {
    
    @Test
    public void testFileWriter() throws Exception{
        //非缓冲区writer
        FileWriter fw = new FileWriter("d:/arch/a.txt");
        fw.write("hello");
        fw.close();
    }
    
    @Test
    public void testBufferedWriter() throws Exception{
        FileWriter fw = new FileWriter("d:/arch/a.txt");
        //非缓冲区writer
        BufferedWriter bw = new BufferedWriter(fw);
        bw.write("hello");
        //bw.flush();
        bw.write("world");
        //bw.flush();
        
        bw.close();
        fw.close();
    }
}

6、

//连接池
public ConnectionPool(String driver,String url,String user,String password){
        try {
            this.driver=driver;
            this.url=url;
            this.user=user;
            this.password=password;
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    public void init() {
        // TODO Auto-generated method stub
        for(int i=0;i<Max;i++){
            try {
                //原生连接
                Connection conn = DriverManager.getConnection(url, user, password);
                connections.add(new WrappedConnection(conn, this));
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
    //回收连接
    public synchronized void add(WrappedConnection c) {
        connections.add(c);
    }
    public synchronized Connection get() {
        if(connections.isEmpty()){
            return null;
        }
        return connections.remove(0);
    }

}
//连接池测试
public class TestConnectionPool {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        MyDataSource ds=new MyDataSource();
        try {
            Connection conn = ds.getConnection();
            PreparedStatement pst = conn.prepareStatement("insert into student values(7,'lis','henan')");
            pst.executeUpdate();
            pst.close();
            conn = ds.getConnection();
             pst = conn.prepareStatement("insert into student values(8,'lise','henan')");
            pst.executeUpdate();
            pst.close();
            conn = ds.getConnection();
             pst = conn.prepareStatement("insert into student values(9,'lisr','henan')");
            pst.executeUpdate();
            pst.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

//池连接包装类
public class WrappedConnection extends ConnectionAdapter {
    private Connection rawConn;
    private ConnectionPool pool;
    
    public WrappedConnection(Connection rawConn, ConnectionPool pool) {
        super();
        this.rawConn = rawConn;
        this.pool = pool;
    }

    @Override
    public void commit() throws SQLException {
        rawConn.commit();
    }

    @Override
    public void rollback() throws SQLException {
        rawConn.rollback();
    }
//关闭连接
    @Override
    public void close() throws SQLException {
        pool.add(this);
        rawConn.close();
    }

    @Override
    public PreparedStatement prepareStatement(String sql) throws SQLException {
        return rawConn.prepareStatement(sql);
    }
}

//适配器
public class ConnectionAdapter implements Connection {
    
    @Override
    public <T> T unwrap(Class<T> iface) throws SQLException {
        // TODO Auto-generated method stub
        return null;
    }
。。。。
}

//数据源
public class MyDataSource implements DataSource {
    private ConnectionPool pool;
     public MyDataSource() {
         String driver="com.mysql.jdbc.Driver";
         String url="jdbc:mysql://localhost:3306/big";
         String user="root";
         String password="root";
         pool=new ConnectionPool(driver,url,user,password);
         //初始化连接池
         pool.init();
    }
     @Override
     public Connection getConnection() throws SQLException {
         // TODO Auto-generated method stub
         return pool.get();
     }
    @Override
    public PrintWriter getLogWriter() throws SQLException {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public void setLogWriter(PrintWriter out) throws SQLException {
        // TODO Auto-generated method stub

    }