Java对象为空的判断

/**
     * 判断对象或对象数组中每一个对象是否为空: 对象为null，字符序列长度为0，集合类、Map为empty
     *
     * @param obj
     * @return
     */
    public  static  boolean  isNullOrEmpty(Object obj) {
        if  (obj ==  null )
            return  true ;

        if  (obj  instanceof  CharSequence)
            return  ((CharSequence) obj).length() ==  0 ;

        if  (obj  instanceof  Collection)
            return  ((Collection) obj).isEmpty();

        if  (obj  instanceof  Map)
            return  ((Map) obj).isEmpty();

        if  (obj  instanceof  Object[]) {
            Object[] object = (Object[]) obj;
            if  (object.length ==  0 ) {
                return  true ;
            }
            boolean  empty =  true ;
            for  ( int  i =  0 ; i < object.length; i++) {
                if  (!isNullOrEmpty(object[i])) {
                    empty =  false ;
                    break ;
                }
            }
            return  empty;
        }
        return  false ;
    }
应用场景：
读取excel文件，转化为一个二维数组：Object[][] arrays
但是excel中有空行，所以需要过滤Object[][] arrays中的空的一维数组：
Java代码
/***
     * 过滤数组中的空元素
     *
     *
     * @param arrays
     * @return
     */
    public  static  Object[][] filterEmpty(Object[][] arrays) {
        int  sumNotNull =  0 ;
        /***
         * 统计非空元素的总个数
         */
        for  ( int  i =  0 ; i < arrays.length; i++) {
            Object object = arrays[i];
            if  (!ValueWidget.isNullOrEmpty(object)
                    && !SystemUtil.isNullOrEmpty((Object[]) object)) { // 判断元素是否为空
                sumNotNull = sumNotNull +  1 ;
            }
        }
        Object[][] filtedObjs =  new  Object[sumNotNull][];
        int  index =  0 ;
        for  ( int  i =  0 ; i < arrays.length; i++) {
            Object[] object_tmp = arrays[i];
            if  (!ValueWidget.isNullOrEmpty(object_tmp)
                    && !SystemUtil.isNullOrEmpty((Object[]) object_tmp)) { // 判断元素是否为空
                filtedObjs[index++] = object_tmp;
            }
        }
        return  filtedObjs;
    }
判断对象的所有成员变量是否为空
Java代码
/***
     * Determine whether the object's fields are empty
     *
     * @param obj
     * @param isExcludeZero  :true:数值类型的值为0,则当做为空;----false:数值类型的值为0,则不为空
     *
     * @return
     * @throws SecurityException
     * @throws IllegalArgumentException
     * @throws NoSuchFieldException
     * @throws IllegalAccessException
     */
    public  static  boolean  isNullObject(Object obj,  boolean  isExcludeZero)
            throws  SecurityException, IllegalArgumentException,
            NoSuchFieldException, IllegalAccessException {
        if (ValueWidget.isNullOrEmpty(obj)){ //对象本身就为null
            return  true ;
        }
        List fieldList = ReflectHWUtils.getAllFieldList(obj.getClass());
        boolean  isNull =  true ;
        for  ( int  i =  0 ; i < fieldList.size(); i++) {
            Field f = fieldList.get(i);
            Object propertyValue =  null ;
            try  {
                propertyValue = getObjectValue(obj, f);
            }  catch  (NoSuchFieldException e) {
                e.printStackTrace();
            }

            if  (!ValueWidget.isNullOrEmpty(propertyValue)) { // 字段不为空
                if  (propertyValue  instanceof  Integer) { // 是数字
                    if  (!((Integer) propertyValue ==  0  && isExcludeZero)) {
                        isNull =  false ;
                        break ;
                    }
                }  else  if  (propertyValue  instanceof  Double) { // 是数字
                    if  (!((Double) propertyValue ==  0  && isExcludeZero)) {
                        isNull =  false ;
                        break ;
                    }
                } else  if  (propertyValue  instanceof  Float) { // 是数字
                    if  (!((Float) propertyValue ==  0  && isExcludeZero)) {
                        isNull =  false ;
                        break ;
                    }
                } else  if  (propertyValue  instanceof  Short) { // 是数字
                    if  (!((Short) propertyValue ==  0  && isExcludeZero)) {
                        isNull =  false ;
                        break ;
                    }
                } else  {
                    isNull =  false ;
                    break ;
                }
            }
        }
        return  isNull;
    }
 测试:
Java代码
@Test
    public  void  test_isNullObject()  throws  SecurityException,
            IllegalArgumentException, NoSuchFieldException,
            IllegalAccessException {
        Person2 p =  new  Person2();
        Assert.assertEquals( true , ReflectHWUtils.isNullObject(p,  true ));
        Assert.assertEquals( false , ReflectHWUtils.isNullObject(p,  false ));

        p.setAddress( "beijing" );
        Assert.assertEquals( false , ReflectHWUtils.isNullObject(p,  true ));
        Assert.assertEquals( false , ReflectHWUtils.isNullObject(p,  false ));

        p.setAddress( null );
        p.setId( 0 );
        Assert.assertEquals( true , ReflectHWUtils.isNullObject(p,  true ));
        Assert.assertEquals( false , ReflectHWUtils.isNullObject(p,  false ));

    }
 Person2 源代码(省略getter,setter方法):
Java代码
import  java.sql.Timestamp;

public  class  Person2 {
    private  int  id;
    private  int  age;
    private  double  weight;
    private  String personName;
    private  Timestamp birthdate;
    public  String identitify;
    protected  String address;
    String phone;

}