這裏允許的servlet

Question

void類型不這是我的java類：

public String year, title,detail; 
public League(String year,String title,String detail) 
{ 
    this.year=year; 
    this.title=title; 
    this.detail=detail; 
} 
public void getTitle() 
{ 
    System.out.println(""+year+""+title+""+detail+""); 
} 

這是我的servlet：

 protected void doGet(HttpServletRequest request, HttpServletResponse response) 
     throws ServletException, IOException { 
    processRequest(request, response); 
    //Creats the set of league 
    leagueList=new LinkedList(); 
    leagueList.add(new League("2003","Spring","Soccer League(Spring`03)")); 
    leagueList.add(new League("2003","Summer","Summer Soccer Fest")); 
    leagueList.add(new League("2003","Fall","Fall Soccer League")); 
    leagueList.add(new League("2004","Spring","Summer Soccer Fest")); 
    leagueList.add(new League("2004","Summer","Soccer League(Spring`03)")); 
    leagueList.add(new League("2004","Fall","Fall Soccer League")); 
} 

這是我的processRequest（）方法

out.println("<ul>"); 
     Iterator items=leagueList.iterator(); 
     while(items.hasNext()){ 
      out.println("<li>"+League.getTitle()+"</li>"); 
     } 
     out.println("</ul>"); 

錯誤是：League.getTitle（）; // void type not allowed

Answer 1

該錯誤非常具有描述性。您正在返回void，換句話說，getTitle方法不會返回任何內容。 Java不能將void（Nothing）的結果連接到String。

更改方法成爲一個適當的getter：

public String getTitle() { 
    return title; 
} 

此外，創建其他字段正確getter方法，以及：

//year field should be an int rather than a String 
public String getYear() { 
    return year; 
} 

public String getDetail() { 
    return detail; 
} 

Answer 2

getTitle()返回任何（void）和你試圖將其添加到字符串。

使用此：

public String getTitle() 
{ 
    return year + title + detail; 
}