//抽象處理者 
public abstract class Handler{ 
 private Handler nextHandler; 
 //每個(gè)處理者都必須對(duì)請(qǐng)求做出處理 
 public final Response handleMessage(Request request){ 
   Response response = null; 
   //判斷是否自己的處理級(jí)別 
   if(this.getHandlerLevel().equals(request.getRequestLevel())){ 
    response = this.echo(request); 
   }else{ 
    //判斷是否有下一個(gè)處理者 
    if(this.nextHandler != null){ 
     response = this.nextHandler.handleMessage(request); 
    }else{ 
     //沒有適當(dāng)?shù)奶幚碚?
   } 
  } 
  return response; 
 } 
 //設(shè)置下一個(gè)處理者是誰 
 public void setNext(Handler _handler){ 
   this.nextHandler = _handler; 
 }  
 //每個(gè)處理者都有一個(gè)處理級(jí)別 
 protected abstract Level getHandlerLevel(); 
 //每個(gè)處理者都必須實(shí)現(xiàn)處理任務(wù) 
 protected abstract Response echo(Request request); 
} 
 
 //具體處理者1 
publlic class ConcreteHandler1 extends Handler{ 
  //定義自己的處理邏輯 
  protected Response echo(Request request){ 
   //完成處理邏輯 
   return null; 
  } 
  //設(shè)置自己的處理級(jí)別 
  protected Level getHandlerLevel(){ 
   //設(shè)置自己的處理級(jí)別 
   return null; 
  } 
} 
 
//具體處理者2 
publlic class ConcreteHandler2 extends Handler{ 
  //定義自己的處理邏輯 
  protected Response echo(Request request){ 
   //完成處理邏輯 
   return null; 
  } 
  //設(shè)置自己的處理級(jí)別 
  protected Level getHandlerLevel(){ 
   //設(shè)置自己的處理級(jí)別 
   return null; 
  } 
}  
 
//具體處理者3 
publlic class ConcreteHandler3 extends Handler{ 
  //定義自己的處理邏輯 
  protected Response echo(Request request){ 
   //完成處理邏輯 
   return null; 
  } 
  //設(shè)置自己的處理級(jí)別 
  protected Level getHandlerLevel(){ 
   //設(shè)置自己的處理級(jí)別 
   return null; 
  } 
}  
 
//模式中有關(guān)框架的代碼 
public class Level{ 
 //定義一個(gè)請(qǐng)求和處理等級(jí) 
}  
public class Request{ 
 //請(qǐng)求的等級(jí) 
 public Level getRequestLevel(){ 
  return null; 
 } 
｝ 
public class Response{ 
 //處理返回者的數(shù)據(jù) 
} 
 
//場(chǎng)景類 
public class Client{ 
 public static void main(String[] args){ 
   //聲明所有的處理節(jié)點(diǎn) 
   Handler handler1 = new ConcreteHandler1(); 
   Handler handler2 = new ConcreteHandler2(); 
   Handler handler2 = new ConcreteHandler3(); 
   //設(shè)置鏈中的階段順序1-->2-->3 
   handler1.setNext(handler2); 
   handler2.setNext(handler3); 
   //提交請(qǐng)求 
   Response response = handler.handleMessage(new Request()); 
 } 
｝