链接的 ViewScoped bean 导致内存泄漏

Question

在我们的 JBoss 7.1.1 上的 JavaEE6 项目（EJB3、JSF2）中，我们似乎有 @ViewScoped bean 的内存泄漏。上树的日子我花时间研究这个问题。所以我创建了一个包含两个页面的简单项目，以保证在离开@ViewScoped bean 的第一页之后将被释放。

<context-param>  //web.xml
   <param-name>javax.faces.STATE_SAVING_METHOD</param-name>
   <param-value>server</param-value>
</context-param>
<context-param>
   <param-name>javax.faces.PARTIAL_STATE_SAVING</param-name>
   <param-value>false</param-value>
</context-param>

TreeBean.java

@ManagedBean
@ViewScoped
public class TreeBean implements Serializable {
 private TreeNode root;  
 public static AtomicInteger count = new AtomicInteger(0);

@Override
protected void finalize() throws Throwable {
    System.out.println("TreeBean beans count: " + count.decrementAndGet() + " (FINALISATION)");
}


public TreeBean() {  
    super();
    System.out.println("TreeBean beans count: " + count.incrementAndGet() + " (INITIALISATION)");
}  

first.xhtml

  ....
  <h:form id="frm">
        <p:tree
            value="#{treeBean.root}"
            var="node"
            id="tree">
    ....
   <p:commandLink
            action="second.xhtml?faces-redirect=true"
            value="toSecond" />
    ....            

second.xhtml

  ....
  <h:form id="frm">
    ....
   <p:commandLink
            action="first.xhtml?faces-redirect=true"
            value="toFirst" />
    ....

系统输出：

  INFO  [stdout] (http--0.0.0.0-8080-4) TreeBean beans count: 1 (INITIALISATION)
  INFO  [stdout] (http--0.0.0.0-8080-4) TreeBean beans count: 2 (INITIALISATION)
  INFO  [stdout] (http--0.0.0.0-8080-4) TreeBean beans count: 3 (INITIALISATION)
  ......
  INFO  [stdout] (Finalizer) TreeBean beans count: 2 (FINALISATION)
  INFO  [stdout] (Finalizer) TreeBean beans count: 1 (FINALISATION)
  INFO  [stdout] (Finalizer) TreeBean beans count: 0 (FINALISATION)

在我将依赖项添加到其他 @ViewScoped bean 之前，一切都很好

TreeBean.java

@ManagedBean
@ViewScoped
public class TreeBean implements Serializable {
 private TreeNode root;  

@ManagedProperty(value = "#{treeNodeBean}")
private TreeNodeBean treeNodeBean;


 public static AtomicInteger count = new AtomicInteger(0);

@Override
protected void finalize() throws Throwable {
    System.out.println("TreeBean beans count: " + count.decrementAndGet() + " (FINALISATION)");
}


public TreeBean() {  
    super();
    System.out.println("TreeBean beans count: " + count.incrementAndGet() + " (INITIALISATION)");
}  

TreeNodeBean.java

@ManagedBean
@ViewScoped
public class TreeNodeBean implements Serializable {

     private String treeNodeItem="TreeNodeItem";

}

之后没有一个 bean 被释放。有人知道如何处理吗？这是一个错误还是可能在某处配置？

Answer 1

不幸的是，您是对的，@ViewScoped 内存管理存在已知问题（并且不关心仅链接视图），您将看到here 和here。另请查看this question，您可以尝试在当前会话中获取UIViewRoot 对象并根据某些事件调用getViewMap().remove("myView")。你也可以试试this

与此无关，您为什么要链接视图范围的 bean？它们旨在按名称使用，用于视图。您是否限制使用SessionScoped？