结构型模式

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发布时间：2019-06-22

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结构模式

适配器模式

类的适配器模式

创建一个Source类，拥有一个方法待适配

public class Source {  public void method1(){      System.out.println("method1");  }}

创建目标接口Targetable

public interface Targetable {  void method1();  void method2();}

创建Adapter类，将Source类的功能扩展到Targetable中

public class Adapter extends Source implements Targetable {  @Override  public void method2() {      System.out.println("method2");  }}

对象的适配器方式

创建一个Source类

public class Source {  public void method1(){      System.out.println("method1");  }}

创建目标接口Targetable

public interface Targetable {  void method1();  void method2();}

创建Adapter类

public class Adapter  implements Targetable {  private Source source;  public Adapter(Source source){      this.source=source;  }  @Override  public void method1() {      source.method1();  }  @Override  public void method2() {      System.out.println("method2");  }}

接口的适配器模式

创建目标接口Targetable

public interface Targetable {  void method1();  void method2();}

创建一个Source类

public abstract class Source implements Targetable {    public void method1(){    }  }

创建Adapter类

public class Adapter  extends Source {    @Override    public void method2() {        System.out.println("method2");    }  }

装饰模式

创建Sourceable接口

public interface Sourceable {    void method();}

创建Source类

public class Source implements Sourceable {    @Override    public void method() {        System.out.println("the original method!");    }}

创建Decorator类

public class Decorator implements Sourceable {    private Sourceable source;    public Decorator(Sourceable source) {        this.source = source;    }    @Override    public void method() {        System.out.println("before decorator!");        source.method();        System.out.println("after decorator!");    }}

代理模式

创建Sourceable接口

public interface Sourceable {     void method();}

创建Source类

public class Source implements Sourceable {    @Override    public void method() {        System.out.println("the original method!");    }}

创建Proxy类

public class Proxy implements Sourceable {    private Sourceable source;    public Proxy(Sourceable source) {        this.source = source;    }    @Override    public void method() {        System.out.println("before Proxy!");        source.method();        System.out.println("after Proxy!");    }}

外观模式

外观模式创建CPU类

public class CPU {  public void startup() {      System.out.println("cpu startup!");  }  public void shutdown() {      System.out.println("cpu shutdown!");  }}

创建Disk类

public class Disk {  public void startup(){      System.out.println("disk startup!");  }  public void shutdown(){      System.out.println("disk shutdown!");  }}

创建Memory类

public class Memory {  public void startup(){      System.out.println("memory startup!");  }  public void shutdown(){      System.out.println("memory shutdown!");  }}

创建Computer类

public class Computer {  private CPU cpu;  private Memory memory;  private Disk disk;  public Computer(){      cpu = new CPU();      memory = new Memory();      disk = new Disk();  }  public void startup(){      System.out.println("start the computer!");      cpu.startup();      memory.startup();      disk.startup();      System.out.println("start computer finished!");  }  public void shutdown(){      System.out.println("begin to close the computer!");      cpu.shutdown();      memory.shutdown();      disk.shutdown();      System.out.println("computer closed!");  }}

桥接模式

创建接口

public interface Sourceable {     void method();}

创建实现类

public class Source implements Sourceable {    @Override    public void method() {        System.out.println("this is the Source");    }}

创建抽象类

public abstract class Bridge {    private Sourceable source;    public void method(){        source.method();    }    public Sourceable getSource() {        return source;    }    public void setSource(Sourceable source) {        this.source = source;    }}

创建抽象继承类

public class MyBridge extends Bridge {    public void method(){        getSource().method();    }}

组合模式

public class TreeNode {    private String name;    private TreeNode parent;    private Vector
      
        children = new Vector
       
        ();    public TreeNode(String name){        this.name = name;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public TreeNode getParent() {        return parent;    }    public void setParent(TreeNode parent) {        this.parent = parent;    }    //添加孩子节点    public void add(TreeNode node){        children.add(node);    }    //删除孩子节点    public void remove(TreeNode node){        children.remove(node);    }    //取得孩子节点    public Enumeration
        
          getChildren(){        return children.elements();    }}

享元模式

public class ConnectionPool {    private Vector
      
        pool;    /*公有属性*/    private String url = "jdbc:mysql://localhost:3306/test";    private String username = "root";    private String password = "root";    private String driverClassName = "com.mysql.jdbc.Driver";    private int poolSize = 100;    private static ConnectionPool instance = null;    Connection conn = null;    /*构造方法，做一些初始化工作*/    private ConnectionPool() {        pool = new Vector
       
        (poolSize);        for (int i = 0; i < poolSize; i++) {            try {                Class.forName(driverClassName);                conn = DriverManager.getConnection(url, username, password);                pool.add(conn);            } catch (ClassNotFoundException e) {                e.printStackTrace();            } catch (SQLException e) {                e.printStackTrace();            }        }    }    /* 返回连接到连接池 */    public synchronized void release() {        pool.add(conn);    }    /* 返回连接池中的一个数据库连接 */    public synchronized Connection getConnection() {        if (pool.size() > 0) {            Connection conn = pool.get(0);            pool.remove(conn);            return conn;        } else {            return null;        }    }}