标签: classcastexception

尝试使用Hibernate 3.6和MySQL5.1选择一个实体,但我不断得到一个ClassCastException.

@Entity
@Table( name = "USER" )
public class User {
   @Id
   @Column(name= "user_id")
   private Long userId;

   @OneToOne()
   @JoinColumn(name="status_id")
   protected UserStatusType userStatusType;

   @OneToOne()
   @JoinColumn(name="region_id")
   protected Region region;


@Entity
@Table( name = "REGION" )
public class Region   
   @Id
   @Column(name = "region_id")
   private Long regionId


@Entity
@Table( name = "USER_STATUS_TYPE" )
public class UserStatusType  
   @Id
   @Column(name = "type_id")
   private Long typeId

在createQuery()中尝试使用HQL时,我不断收到ClassCastException:

session.beginTransaction();
User user = (User)session.createQuery(
   "from User u, UserStatusType ust, Region r "
   + " where u.userId = ? …

我最近决定在我的应用程序中添加一个ViewFlipper,这是我所做的:

main.xml中

<?xml version="1.0" encoding="utf-8"?>
<ViewFlipper xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/steve"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    // Child elements here.

</ViewFlipper>

MyApp.java

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);
    ViewFlipper viewFlipper = (ViewFlipper)findViewById(R.id.steve);

但是,当我运行我的应用程序时,我得到了一个java.lang.ClassCastException: android.widget.Button用于转换为ViewFlipper的行.

经过调试,结果是findViewById(R.id.steve)返回一个Button,而不是一个ViewFlipper.

我怎样才能解决这个问题？

我遇到了以下代码的问题.类id为Long,B类id是嵌入式id,其中一个字段为A类.

DetachedCriteria dc = DetachedCriteria.forClass(A.class,"a").setProjection(Property.forName("a.id"));      
Criteria cr= this.sessionFactory.getCurrentSession().createCriteria(B.class,"b").add(Subqueries.in("b.id.a.id", dc));           
List<B> bb = cr.list();

这给出了例外:

java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Long

但是这个:

List<Long> dd =  this.sessionFactory.getCurrentSession().createCriteria(A.class,"a").setProjection(Property.forName("a.id")).list();
Criteria cr= this.sessionFactory.getCurrentSession().createCriteria(B.class,"b").add(Restrictions.in("b.id.a.id", dd));


List<B> bb = cr.list();

作品.我究竟做错了什么？

我想要处理其中一个菜单项(我用XML声明这个).

    <item android:id="@+id/menu_shape_shifter"
    android:title="@string/menu_search"
    android:icon="@drawable/ic_action_refresh"
    android:orderInCategory="0"
    android:visible="true"
    android:showAsAction="always" />

所以我这样做, MenuItem item_shape_shifter = (MenuItem)findViewById(R.id.menu_shape_shifter); 但它失败并出现异常:ClassCastException:com.android.internal.view.menu.ActionMenuItemView无法强制转换为android.view.MenuItem.

如果没有获得此菜单项的句柄,我无法继续.但是,找不到任何线索.

注意:我正在使用Action Bar兼容包,因为我支持的版本<3.0

try{
 System.out.println(surveyReportList.get(0).getEmploymentStatus());
}
catch(Exception e){
 System.out.println(e.getCause());
 e.printStackTrace();
}

我正在尝试获取列表中的一个字段值,并且我收到了ClassCastException.我使用的列表大小合适surveyReportList.size();.

这是堆栈跟踪,我surveyReportList的类型是List<SurveyReport>第103行try.

at com.action.survey.SurveyReportAction.generateReports(SurveyReportAction.java:103)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:441)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:280)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:243)
    at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252)
    at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:179)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) …

我试图从数据库中检索值并将其存储在List,

数据被检索并正常工作,但当我转换List成Object<pojo class>我得到一个例外,

我的代码是

Query qry=session.createQuery("select personaldetails.fname,personaldetails.lname from Personaldetails as personaldetails where refId=1001");
List<Personaldetails> l=(List<Personaldetails>)qry.list();
session.getTransaction().commit();
session.close();
System.out.println("--->"+l.size());  //List 'l' holds the values from DB
Personaldetails p; //This is an pojo class
p=(Personaldetails)l.get(i);  //Here i am getting the exception here
System.out.println("Person name "+p.getFname());

在上面提到的行我得到了Exception ClassCastException,我不知道为什么,我试过它在编译时没有显示错误.

任何建议将不胜感激....

我使用ION(https://github.com/koush/ion)从网页中的图像加载到ListView的ImageView.目前我想从中获取位图ImageView,但是我得到一个强制关闭我的应用程序的异常:

java.lang.ClassCastException: com.koushikdutta.ion.IonDrawable cannot be cast to android.graphics.drawable.BitmapDrawable

这些是我正在使用的行:

final ImageView itemImageView = (ImageView)view.findViewById(R.id.photoImage);
final Bitmap itemDrawable = ((BitmapDrawable) itemImageView.getDrawable()).getBitmap();

我怎么解决这个问题？提前致谢!

我想得到 PGConnection从 JBOSS AS7 中的 PosgreSQL 连接（数据源 postgresql-9.0-801.jdbc4.jar）

我在使用时遇到了强制转换异常(WrappedConnection)connection。所以现在我使用反射（JDK 1.7）：

private static PGConnection getPGConnction(Connection connection) throws SQLException {
    if(connection instanceof PGConnection) {
        return (PGConnection)connection;
    }
    try {
        Class[] parms = null;
        Method method =(connection.getClass()).getMethod("getUnderlyingConnection", parms);
        return (PGConnection) jdbc4Conn;
    } catch ...

并捕获异常

java.lang.ClassCastException: org.postgresql.jdbc4.Jdbc4Connection cannot be cast to org.postgresql.jdbc4.Jdbc4Connection

是同一个班！！！怎么会这样？

因此,ClassCastException当我试图将我投入我的时Node<T>,我会得到这个AVLNode<T>.不知道为什么.

这是它抛出异常的地方.

Node<Integer> n1 = new Node<Integer>(3, null);
    AVLNode<Integer> n2 = (AVLNode<Integer>) n1;

课程看起来如何......

public class Node<T extends Comparable<T>> {

public Node<T> right;

public Node<T> left;

public Node<T> parent;

public T data;

public Node(T data, Node<T> parent) {
    this.data = data;
    this.parent = parent;
} // ...

而另一个类在单独的文件中:

public class AVLNode<T extends Comparable<T>> extends Node<T> {

public int height = 1;

public AVLNode(T data, Node<T> parent) {
    super(data, parent);
} //...

错误消息:线程"main"中的异常java.lang.ClassCastException:custom.trees.Node无法强制转换为custom.trees.AVLNode

嗨,我是Java的新手,在这段代码中,我想我不是在Main中正确创建Bag？请帮忙谢谢!

线程"main"中的异常java.lang.ClassCastException:[Ljava.lang.Object; 无法转换为[Ljava.lang.Comparable; atBag.(Bag.java:12)mid.Bag.main(Bag.java:91)

        public class Bag<T extends Comparable<T>> implements Iterable<T> {
      private int MAX_ITEMS = 10; // initial array size
      private int size;
      private T[] data;

      public Bag( ) {
        data = (T []) new Object[MAX_ITEMS];
        size = 0;
      }

      public void add(T newItem) {
        // check if it's full, then extend (array resizing)
        if (size == data.length) {
          T[ ] temp = (T [ ] ) new Object[data.length*2];
          for (int i = 0; i < size; ++i)
            temp[i] …