併發服務器上的共享計數器未按預期遞增

我試圖存儲任何客戶端從ServerProtocol類請求描述的次數。併發服務器上的共享計數器未按預期遞增

目前，每次新客戶端加入時，計數器將從零開始遞增。有任何想法嗎？

Counter類：

從ServerProtocol類

public class Counter { 

private int counter; 

public synchronized int get() { 
    return counter; 
} 

public synchronized void set(int n) { 
    counter = n; 
} 

public synchronized void increment() { 
    set(get() + 1); 
} 
}

段：

case OPTIONS: 
      if (theInput.equals("1")) { 
       theOutput = "computer program description here -- Another? Y or N"; 
       counter.increment(); 
       System.out.println(counter.get()); 
       state = ANOTHER;

println方法上面打印計數器的當前值成在服務器類的終端：

ServerProtocol種類：

public class ServerProtocol { 

private static final int TERMS = 0; 
private static final int ACCEPTTERMS = 1; 
private static final int ANOTHER = 2; 
private static final int OPTIONS = 3; 
private int state = TERMS; 

public String processInput(String theInput) { 
    String theOutput = null; 

    Counter counter = new Counter(); 

    switch (state) { 
     case TERMS: 
      theOutput = "Terms of reference. Do you accept? Y or N"; 
      state = ACCEPTTERMS; 
      break; 
     case ACCEPTTERMS: 
      if (theInput.equalsIgnoreCase("y")) { 
       theOutput = "1. computer program 2. picture 3. e-book"; 
       state = OPTIONS; 
      } else if (theInput.equalsIgnoreCase("n")) { 
       theOutput = "Bye."; 
      } else { 
       theOutput = "Invalid Entry -- Terms of reference. Do you accept? Y or N"; 
       state = ACCEPTTERMS; 
      } 
      break; 
     case ANOTHER: 
      if (theInput.equalsIgnoreCase("y")) { 
       theOutput = "1. computer program 2. picture 3. e-book"; 
       state = OPTIONS; 
      } else if (theInput.equalsIgnoreCase("n")) { 
       theOutput = "Bye."; 
      } else { 
       theOutput = "Invalid Entry -- Another? Y or N"; 
       state = ACCEPTTERMS; 
      } 
      break; 
     case OPTIONS: 
      if (theInput.equals("1")) { 
       theOutput = "computer program description here -- Another? Y or N"; 
       counter.increment(); 
       counter.get(); 
       state = ANOTHER; 

      } else if (theInput.equals("2")) { 
       theOutput = "picture description here -- Another? Y or N"; 
       state = ANOTHER; 

      } else if (theInput.equals("3")) { 
       theOutput = "e-book description here -- Another? Y or N"; 
       state = ANOTHER; 

      } else { 
       theOutput = "Invalid Entry -- 1. computer program 2. picture 3. e-book"; 
       state = OPTIONS; 
      } 
      break; 
     default: 
      System.out.println("Oops"); 
    } 

    return theOutput; 
} 
}

來源

2011-12-14 newToJava

您是否每次客戶端加入時都調用processInput？每次調用該方法時，都會創建一個新的計數器。 – Megacan 2011-12-14 19:19:46